Articoli di riviste: "Control of larvae"

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Chen, Shicheng, Michael G. Kaufman, Michelle L. Korir e Edward D. Walker. "Ingestibility, Digestibility, and Engineered Biological Control Potential of Flavobacteriumhibernum, Isolated from Larval Mosquito Habitats". Applied and Environmental Microbiology 80, n. 3 (2 dicembre 2013): 1150–58. http://dx.doi.org/10.1128/aem.03319-13.

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ABSTRACTFlavobacteriumhibernum, isolated from larval habitats of the eastern tree hole mosquito,A. triseriatus, remained suspended in the larval feeding zone much longer (8 days) than other bacteria. Autofluorescent protein markers were developed for the labeling ofF. hibernumwith a strong flavobacterial expression system. Green fluorescent protein (GFP)-taggedF. hibernumcells were quickly consumed by larval mosquitoes at an ingestion rate of 9.5 × 104/larva/h. The ingestedF. hibernumcells were observed mostly in the foregut and midgut and rarely in the hindgut, suggesting that cells were digested and did not pass the gut viably. The NanoLuc luciferase reporter system was validated for quantitative larval ingestion rate and bacterial fate analyses. Larvae digested 1.87 × 105cells/larva/h, and fewF. hibernumcells were excreted intact. Expression of the GFP::Cry11A fusion protein with the P20 chaperone protein fromBacillus thuringiensisH-14 was successfully achieved inF. hibernum. Whole-cell bioassays of recombinantF. hibernumexhibited high larvicidal activity againstA. triseriatusin microplates and in microcosms simulating tree holes.F. hibernumcells persisted in microcosms at 100, 59, 30, and 10% of the initial densities at days 1, 2, 3, and 6, respectively, when larvae were absent, while larvae consumed nearly all of theF. hibernumcells within 3 days of their addition to microcosms.

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Nazaire Aïzoun. "Anopheles gambiae s. l. larval control: An important method for malaria control". World Journal of Biology Pharmacy and Health Sciences 6, n. 3 (30 giugno 2021): 027–34. http://dx.doi.org/10.30574/wjbphs.2021.6.3.0043.

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The current study aimed to investigate on the control tools against larvae and adults of Anopheles gambiae s. l. and then explore the detoxification enzymes mechanisms conferring permethrin tolerance in Anopheles gambiae s. l. larvae in Benin. Larvae and pupae were collected from March to July and August to November 2018 during the rainy season in Bopa district in Mono department in south-western Benin, West Africa. Larval bioassays were performed on these collected Anopheles gambiae s. l. larvae using permethrin as larvicide and synergist piperonyl butoxide (PBO) as enzyme inhibitor or synergist. WHO susceptibility tests were also conducted on adult unfed female mosquitoes aged 3-5 days old with impregnated papers of permethrin (0.75%). The results showed that malaria elimination in Benin needs integrated control. Both larvae or pupae and adults malaria vectors must be controlled.

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Tyrrell, Jordan J., Jackson T. Wilbourne, Alisa A. Omelchenko, Jin Yoon e Lina Ni. "Ionotropic Receptor-dependent cool cells control the transition of temperature preference in Drosophila larvae". PLOS Genetics 17, n. 4 (7 aprile 2021): e1009499. http://dx.doi.org/10.1371/journal.pgen.1009499.

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Temperature sensation guides animals to avoid temperature extremes and to seek their optimal temperatures. The larval stage of Drosophila development has a dramatic effect on temperature preference. While early-stage Drosophila larvae pursue a warm temperature, late-stage larvae seek a significantly lower temperature. Previous studies suggest that this transition depends on multiple rhodopsins at the late larval stage. Here, we show that early-stage larvae, in which dorsal organ cool cells (DOCCs) are functionally blocked, exhibit similar cool preference to that of wild type late-stage larvae. The molecular thermoreceptors in DOCCs are formed by three members of the Ionotropic Receptor (IR) family, IR21a, IR93a, and IR25a. Early-stage larvae of each Ir mutant pursue a cool temperature, similar to that of wild type late-stage larvae. At the late larval stage, DOCCs express decreased IR proteins and exhibit reduced cool responses. Importantly, late-stage larvae that overexpress IR21a, IR93a, and IR25a in DOCCs exhibit similar warm preference to that of wild type early-stage larvae. These data suggest that IR21a, IR93a, and IR25a in DOCCs navigate early-stage larvae to avoid cool temperatures and the reduction of these IR proteins in DOCCs results in animals remaining in cool regions during the late larval stage. Together with previous studies, we conclude that multiple temperature-sensing systems are regulated for the transition of temperature preference in fruit fly larvae.

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Taira, K., V. Šnábel, N. Okada e Y. Saitoh. "Effect of low temperatures on the infectivity of Toxocara cati larvae parasitized in mouse tissues". Helminthologia 50, n. 2 (1 giugno 2013): 83–86. http://dx.doi.org/10.2478/s11687-013-0112-8.

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AbstractThe infectivity of Toxocara cati larvae in mouse tissues, following storage at 4 °C and −25 °C, was measured using a bioassay in mice. Tissues of donor mice infected with 30-day-old T. cati larvae were stored at 4 °C for 7 and 14 days, and at −25 °C for 24 hours, then tissue larvae were inoculated into recipient mice (n = 6/group). After 15 days, larval burden in recipient mice was assessed by digestion. In the control group, a mean of 42.0 % of the inoculated larvae were established in mice. Storage of tissues at 4 °C for 7 and 14 days did not affect larval infectivity; means of 43.5 % and 37.4 % of inoculated larvae, respectively, were established in mice. Larvae exposed to −25 °C for 24 hours did not establish in mice, except for one larva recovered from a single mouse. These results may support the potential of tissue larvae in livestock animals as a causative agent of human toxocarosis.

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Hansen, J. D., M. A. Watkins, M. L. Heidt e P. A. Anderson. "Cold Storage to Control Codling Moth Larvae in Fresh Apples". HortTechnology 17, n. 2 (aprile 2007): 195–98. http://dx.doi.org/10.21273/horttech.17.2.195.

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Codling moth [Cydia pomonella (Lepidoptera: Tortricidae)], found in exported apples (Malus sylvestris), can disrupt international markets. Cold storage at 1.1 °C was examined for possible control of three physiological larval states in ‘Fuji’ apples: diapausing (overwintering), diapause-destined, and nondiapausing. All nondiapausing larvae were dead within 12 weeks, diapaused-destined larvae were controlled by the seventh week, yet more than half of the original populations of diapausing larvae were still alive after 11 weeks. Because the diapaused-destined larvae were younger than the nondiapausing larvae, they may have been more susceptible to cold. Because larvae normally diapause outside the fruit, cold storage would not be applicable for controlling larvae in this state.

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Khatun, Mousumi, Mohammad Mahir Uddin, Md Azizul Haque e Mohammad Saidur Rhaman. "Feeding, growth and chemical control of hog-plum beetle (Podontia 14- punctata)". Research in Agriculture Livestock and Fisheries 3, n. 3 (18 dicembre 2016): 387–94. http://dx.doi.org/10.3329/ralf.v3i3.30729.

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Experiments were conducted to study the feeding, growth and chemical control of hog-plum beetle (Podontia 14-punctata) in the laboratory and in the field. It was found that larval leaf consumption gradually increased with the increase of age of larva. Mean leaf consumption per larva was 0.28g, 0.86g and 1.70g after 24, 72 and 144 hrs, respectively. Growth pattern of larva was depended on the rate of leaf consumption. The average body weight of larvae was increased with time and per larva was recorded as 0.06g, 0.19g and 0.45g after 24, 72 and 144 hrs of leaf consumption. Daily leaf consumption was higher in adults than larvae. Mean leaf consumption per adult was 0.24g, 0.91g and 1.87g after 24, 72 and 144 hrs, respectively. Mortality of larvae and adults against four chemical insecticides viz. Altima 40WG, Belt 24WG, Libsen 45SC and Limper 10EC were observed both in the laboratory and field. All the treatments had a significant effect on mortality percentage of larva and adult in comparison to control. The highest mortality percentage of the larva (86.67) and adult (80.00) were observed in the case of Limper 10EC at 72 hrs after spraying. However, there was no significant difference observed in efficacy among Limper 10EC, Belt 24WG and Libsen 45SC. In field, percentage of leaf protection over control after 1st spray was the highest (37.95) in Limper 10EC and the lowest (20.86) in Altima 40WG treated plants. The results of laboratory and field trials revealed that Limper 10EC might be recommended for effective control of P. 14-punctata.Res. Agric., Livest. Fish.3(3): 387-394, December 2016

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Dantas, José Oliveira, Talita Guimarães Araújo-Piovezan, Danielle Pereira Santos, Agripino Emanuel Oliveira Alves, Sarita Socorro Campos Pinheiro e Genésio Tâmara Ribeiro. "Extracts of Potential Plants in the Control of the Aedes aegypti Population". Ensaios e Ciência: Ciências Biológicas, Agrárias e da Saúde 23, n. 2 (9 dicembre 2019): 104. http://dx.doi.org/10.17921/1415-6938.2019v23n2p104-108.

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Abstract The dengue fever is a febrile illness transmitted by mosquitoes Aedes aegypti to humans. The control of dengue dissemination is a hard challenge since the human population is presenting a considerably increase. Brazilian plants are known to control mosquitoes larvae due to their insecticides properties. This work had the objective to evaluate the success of plants extracts on the Aedes aegypti population. It was hypothesized that the studied plant extracts influence the population size of Aedes aegypti. It was hoped that at least one of these extracts is 100% efficient on the mosquito larvae combat, thus contributing to Brazilian Health Programs for the local Dengue eradication. Five plants extracts were studied against Aedes aegypti larvae populations under laboratory conditions. The plants were macerated and 4 concentrations for each plant were obtained using distillate water. Each concentration of each extract was tested on 10 Aedes larvae with 3 repetitions, for the experiment and positive and negative control on larvae were tested, using alcohol and mineral water, respectively. The count of dead larvae was daily done. The Ricinus communis L. extract was the best extract against Aedes aegypti, killing 100% of their larvae, followed by Mimosa Tenuiflora and Ipoema eriocalyx that achieved DL50 at a concentration of 20%. These results suggest the use of the Ricinus communis L. extract on the control of A. aegypti population in order to extinct the Dengue fever and to help the government healthy programs with this disease. Keywords: Mosquitoes larvae. Dengue Fever. Medicinal Plants. ResumoA Dengue é uma doença transmitida por mosquitos Aedes aegypti para humanos. Seu controle é uma tarefa árdua, uma vez que a população humana tem apresentado crescimento considerável. Entretanto, plantas brasileiras são indicadas para controle de larvas deste mosquito em função de suas propriedades inseticidas. Este trabalho objetivou avaliar o sucesso de extratos de plantas no controle da população de Aedes aegypti. Foi proposta a hipótese de que os extratos das plantas estudados influenciam no tamanho da população de Aedes aegypti. Esperou-se que pelo menos um destes extratos fosse 100% eficiente no combate às larvas de mosquito, de forma a contribuir para Programas de saúde que visam erradicação da Dengue. Cinco extratos de plantas foram estudados no controle do Aedes aegypti sob condições laboratoriais. As plantas foram maceradas e quatro concentrações foram obtidas de cada uma, utilizando água destilada. Cada concentração foi testada em dez larvas de Aedes com três repetições no experimento e se testou um controle positivo e negativo nas larvas, usando álcool e água destilada, respectivamente. A contagem de larvas mortas foi feita diariamente. O extrato da Ricinus communis L. foi o de maior sucesso no controle de Aedes aegypti, matando 100% das larvas, seguido da Mimosa Tenuiflora e Ipoema eriocalyx, que atingiram DL50 em uma concentração de 20%. O uso de extrato de Ricinus communis L é, portanto, a ferramenta mais indicada para o controle de A. aegypti, auxiliando potencialmente na erradicação da Dengue, e dando diretrizes para programas governamentais de saúde dos países com esta doença. Palavras-chave: Larvas de Mosquitos. Dengue. Plantas Medicinais.

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Makkiah, Makkiah, Cristina L. Salaki e Berty Assa. "Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti)". JURNAL BIOS LOGOS 10, n. 1 (30 dicembre 2019): 1. http://dx.doi.org/10.35799/jbl.10.1.2020.26920.

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Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti) Makkiah*), Cristina L Salaki **), Berty AssaProgram Studi Entomologi Pascasarjana Universitas Sam RatulangiManado, 95155*Email: khiaimoet@gmail.com,**Email korespondensi: christinasalaki@ymail.com (Article History: Received 20-10-2019; Revised 27-11-2019; Accepted 30-12-2019) Abstrak Pengendalian nyamuk sebagai vektor utama penularan penyakit DBD hanya dapat dilakukkan dengan cara memutuskan rantai penularannya melalui pengendalian nyamuk. Pengendalian nyamuk dapat dilakukan pada tahap larva dengan menggunakan biolarvasida yang terbuat dari bahan alami dan salah satunya adalah dengan menggunakan ekstrak kasar dari tanaman serai wangi (Cymbopogon nardus). Penelitian ini bertujuan untuk menguji efektivitas ekstrak serai wangi sebagai larvasida larva Aedes aegypti instar III dan IV. Penelitian ini adalah penelitian eksperimental menggunakan rancangan acak lengkap. Larva yang digunakan adalah larva instar III dan IV, dengan perlakuan konsentrasi ekstrak serai wangi 20%, 30%, 40%, dan 50% dalam 250 ml air. Pada penelitian ini terdapat kontrol yaitu aquades yang tidak ditambahkan larutan apapun. Pengamatan kematian larva dilakukan pada jam ke 1, 3, 6, 12, 24, dan jam ke 48 dengan replikasi sebanyak 4 kali. Data presentase mortalitas larva digunakan untuk menghitung nilai LC50 dan LT50 dengan menggunakan analisisi Probit. Hasil penelitian menunjukkan ekstrak serai wangi efektif dalam mematikan 50% dari populasi larva uji dengan nilai LC50 pada konsentrasi 36,48%serta waktu yang di butuhkan untuk mematikan 50% populasi larva uji adalah 10,45 jam. Kata kunci : Ekstrak, Cymbopogon nardus, larvasida, Aedes aegypti Abstract Control of mosquitoes as the main vector of transmission of DHF can only be done by breaking the chain of transmission through mosquito control. Mosquito control can be carried out at the larval stage by using biolarvasides made from natural materials, one of which is by using a crude extract from the citronella plant (Cymbopogon nardus). This research is to find out the effectiveness of citronella extract as larvae of Aedes aegypti larvae instar III and IV. This research is a pure experimental study using a complete random design. The larvae used were instar larvae III and IV, with the treatment of citronella extract concentration of 20%, 30%, 40%, and 50% in 250 ml of water. In this study, there was a control i.e. aquades which did not add any solution. Observation of larvae death was done at 1 hour, 2 hours. 4 hours, 12 hours, 24 hours and 28 hours with replication 4 times. Data on larval mortality were used to calculate LC50 and LT 50 values using Probit regression analysis. The results showed that citronella extract was effective in killing 50% of the population of test larvae with LC50 values at a concentration of 36.48% and the time needed to kill 50% of the population of test larvae was 10,450 hours.Key words: Extract, Cymbopogon nardus, larvasida, Aedes aegypti

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Duan, Jian J., Leah S. Bauer, Roy Van Driesche, Jonathan M. Schmude, Toby Petrice, Jennifer L. Chandler e Joe Elkinton. "Effects of Extreme Low Winter Temperatures on the Overwintering Survival of the Introduced Larval Parasitoids Spathius galinae and Tetrastichus planipennisi: Implications for Biological Control of Emerald Ash Borer in North America". Journal of Economic Entomology 113, n. 3 (4 aprile 2020): 1145–51. http://dx.doi.org/10.1093/jee/toaa048.

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Abstract Climate change has been linked to shifts in the distribution and phenology of species although little is known about the potential effects that extreme low winter temperatures may have on insect host–parasitoid interactions. In late January 2019, northern regions of the United States experienced a severe cold wave caused by a weakened jet stream, destabilizing the Arctic polar vortex. Approximately 3 mo later at six study sites in southern Michigan and three in southern Connecticut, we sampled the overwintering larvae of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), and two larval parasitoids, Spathius galinae (Hymenoptera: Braconidae) and Tetrastichus planipennisi (Hymenoptera: Eulophidae), that are being introduced as emerald ash borer biocontrol agents in North America. At these nine study sites, emerald ash borer-infested ash trees and/or saplings were debarked and each overwintering emerald ash borer and parasitoid larva was then examined for cold-induced mortality, as indicated by a brown coloration, flaccid, and watery consistency. In early spring in Michigan, we found 4.5–26% of emerald ash borer larvae, 18–50% of S. galinae larvae, and 8–35% of T. planipennisi larvae were killed by cold. In Connecticut where temperatures were more moderate than in Michigan during the 2019 cold wave, <2% of the larval hosts and parasitoids died from cold injury. Our findings revealed that cold-induced mortality of overwintering larvae of emerald ash borer and its larval parasitoids varied by location and species, with higher mortality of parasitoid larvae in most Michigan sites compared to host larvae. The potential impacts of our findings on the management of emerald ash borer using biocontrol are discussed.

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Pronier, I., J. Paré, J.-C. Wissocq e C. Vincent. "Nucleopolyhedrovirus infection in obliquebanded leafroller (Lepidoptera: Tortricidae)". Canadian Entomologist 134, n. 3 (giugno 2002): 303–9. http://dx.doi.org/10.4039/ent134303-3.

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AbstractA virus isolated from obliquebanded leafroller, Choristoneura rosaceana (Harris), larvae collected in an apple, Malus domestica Borkh. (Rosaceae), orchard of Saint-Joseph-du-Lac (Quebec, Canada) was studied. Microscopic studies revealed that it was a uninucleocapsid nucleopolyhedrovirus from the family Baculoviridae. Larval mortality was approximately 75% (0% mortality in control group) in larvae infected as third instars immersed in a suspension of 1.7 × 108 occlusion bodies/mL. The average time for larval mortality was 23 ± 3 d after treatment. The majority (95.5%) of infected larvae died as fifth or sixth instars. Infection was observed primarily in fat body cells, and occasionally in the tracheal matrix and epidermis. Mean larval development time of infected larvae surviving to pupae was 20 ± 3 d, significantly greater than the 18 ± 3 d observed in control larvae. Adult emergence was significantly lower in pupae of treated larvae (73.6%) than in the control group (93.5%). Our work constitutes the first baseline study of naturally occurring virus of the obliquebanded leafroller.

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Ediriweera, ERHSS. "Evaluation of Anthelmintic properties of Sesbania grandiflora Pers. (Kathurumurunga) against larvae of Toxocara canis and Haemonchus contortus – In Vitro Study". Healer 2, n. 1 (3 febbraio 2021): 42–47. http://dx.doi.org/10.51649/healer.15.

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Sesbania grandiflora is a slender tree. It is a common garden plant in Sri Lanka, which grows well in mid and low country. In Sri Lanka, Sesbania grandiflora is used as a home remedy, in treatment of worm infections in humans. Toxocara canis is a helminth parasite infecting dogs and other canids. It also causes toxocariasis in humans. Haemonchus contortus is a nematode that infects goats and causes anaemia, marked reduction in growth and reproduction, and even death. Using this information, in vitro larvae migratory inhibition assay was carried out on Toxocara canis and Haemonchus contortus larve. This study revealed 98.1% and 94.3% larvae migration inhibition with larvae of Toxocara canis and Haemonchus contortus respectively. Least number of migrated larvae was observed in the positive control Levamisole and all the larvae were dead after migration. In decoction of S.grandiflora, all the migrated Toxocara larvae were dead and Haemonchus larvae were dead or in Grade1 (inactive but occasional movement can be observed) condition. Inhibition of Toxocara larval migration and Haemonchus larval migration with decoction of Sesbania grandiflora and Levamisole are statically significant (p < 0.05). Since mean of LMI (larval migration inhibition) of Levamisole is greater than mean of LMI of Sesbania grandiflora with both larvae, Levamisole is more effective than Sesbania grandiflora. Based on these findings, the aqueous extract of leaves of Sesbania grandiflora is shows a statistically significant anthelmintic activity in in-vitro model.

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Makkiah, Makkiah, Christina L. Salaki e Berty Assa. "Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti". JURNAL BIOS LOGOS 10, n. 1 (30 dicembre 2019): 1. http://dx.doi.org/10.35799/jbl.10.1.2020.27977.

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Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti) Makkiah*), Christina L Salaki **), Berty AssaProgram Studi Entomologi Pascasarjana Universitas Sam RatulangiManado, 95155*Email: khiaimoet@gmail.com,**Email korespondensi: christinasalaki@ymail.com (Article History: Received 20-10-2019; Revised 27-11-2019; Accepted 30-12-2019) AbstrakPengendalian nyamuk sebagai vektor utama penularan penyakit DBD hanya dapat dilakukan dengan cara memutuskan rantai penularannya melalui pengendalian nyamuk. Pengendalian nyamuk dapat dilakukan pada tahap larva dengan menggunakan biolarvasida yang terbuat dari bahan alami dan salah satunya adalah dengan menggunakan ekstrak kasar dari tanaman serai wangi (Cymbopogon nardus). Penelitian ini bertujuan untuk menguji efektivitas ekstrak serai wangi sebagai larvasida larva Aedes aegypti instar III dan IV. Penelitian ini adalah penelitian eksperimental menggunakan rancangan acak lengkap. Larva yang digunakan adalah larva instar III dan IV, dengan perlakuan konsentrasi ekstrak serai wangi 20%, 30%, 40%, dan 50% dalam 250 ml air. Pada penelitian ini terdapat kontrol yaitu aquades yang tidak ditambahkan larutan apapun. Pengamatan kematian larva dilakukan pada jam ke 1, 3, 6, 12, 24, dan jam ke 48 dengan replikasi sebanyak 4 kali. Data presentase mortalitas larva digunakan untuk menghitung nilai LC50 dan LT50 dengan menggunakan analisisi Probit. Hasil penelitian menunjukkan ekstrak serai wangi efektif dalam mematikan 50% dari populasi larva uji dengan nilai LC50 pada konsentrasi 36,48%serta waktu yang di butuhkan untuk mematikan 50% populasi larva uji adalah 10,45 jam. Kata kunci : Ekstrak, Cymbopogon nardus, larvasida, Aedes aegypti AbstractControl of mosquitoes as the main vector of transmission of DHF can only be done by breaking the chain of transmission through mosquito control. Mosquito control can be carried out at the larval stage by using biolarvasides made from natural materials, one of which is by using a crude extract from the citronella plant (Cymbopogon nardus). This research is to find out the effectiveness of citronella extract as larvae of Aedes aegypti larvae instar III and IV. This research is a pure experimental study using a complete random design. The larvae used were instar larvae III and IV, with the treatment of citronella extract concentration of 20%, 30%, 40%, and 50% in 250 ml of water. In this study, there was a control i.e. aquades which did not add any solution. Observation of larvae death was done at 1 hour, 2 hours. 4 hours, 12 hours, 24 hours and 28 hours with replication 4 times. Data on larval mortality were used to calculate LC50 and LT 50 values using Probit regression analysis. The results showed that citronella extract was effective in killing 50% of the population of test larvae with LC50 values at a concentration of 36.48% and the time needed to kill 50% of the population of test larvae was 10,450 hours.Keywords: Extract, Cymbopogon nardus, larvasida, Aedes aegypti

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Lettmann, Jessica, Karsten Mody, Tore-Aliocha Kursch-Metz, Nico Blüthgen e Katja Wehner. "Bracon wasps for ecological pest control–a laboratory experiment". PeerJ 9 (27 maggio 2021): e11540. http://dx.doi.org/10.7717/peerj.11540.

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Biological control of pest insects by natural enemies may be an effective, cheap and environmentally friendly alternative to synthetic pesticides. The cosmopolitan parasitoid wasp species Bracon brevicornis Wesmael and B. hebetor Say (Hymenoptera: Braconidae) use lepidopteran species as hosts, including insect pests like Ephestia kuehniella or Ostrinia nubilalis. Here, we compare the reproductive success of both Bracon species on E. kuehniella in a laboratory experiment. We asked (1) how the reproductive success on a single host larva changes with temperature, (2) how it changes with temperature when more host larvae are present and (3) how temperature and availability of host larvae influence the efficacy of Bracon species as biological control agents. In general, differences between B. brevicornis and B. hebetor have been small. For rearing both Bracon species in the laboratory on one host larva, a temperature between 20–27 °C seems appropriate to obtain the highest number of offspring with a female-biased sex ratio. Rearing the braconid wasps on more than one host larva revealed a higher number of total offspring but less offspring per host larva on average. Again, highest numbers of offspring hatched at 27 °C and the sex ratio was independent from temperature. Although no parasitoids hatched at 12 °C and only few at 36 °C, host larvae were still paralyzed. The efficacy of B. brevicornis was higher than 80% at all numbers of host larvae presented at all temperatures while the efficacy of B. hebetor was less than 80% at 12 °C and 27 °C at low numbers of host larvae presented. In conclusion, practitioners can use either B. brevicornis or B. hebetor at low and high temperatures and at varying host densities to achieve high pest control efficacy.

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Pramanik, Soujita, Sampa Banerjee, Soumyajit Banerjee, Goutam K. Saha e Gautam Aditya. "Observations on the predatory potential of Lutzia fuscana on Aedes aegypti larvae: implications for biological control (Diptera: Culicidae)". Fragmenta Entomologica 48, n. 2 (31 dicembre 2016): 137. http://dx.doi.org/10.4081/fe.2016.176.

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Among the natural predators, larval stages of the mosquito Lutzia fuscana (Wiedemann, 1820) (Diptera: Culicidae) bear potential as a biological control agent of mosquitoes. An estimation of the predatory potential of the larva of L. fuscana against the larva of the dengue vector Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) was made to highlight its use in vector management. Laboratory experiments revealed that the larva of L. fuscana consumes 19 to 24 A. aegypti larvae per day, during its tenure as IV instar larva. The consumption of A. aegypti larvae was proportionate to the body length (BL) and body weight (BW) of the predatory larva L. fuscana as depicted through the logistic regressions: y = 1 / (1 + exp(-(-2.09 + 0.35*BL))) and y = 1 / (1 + exp(-(0.4+ 0.06*BW))). While the prey consumption remained comparable among the days, the net weight gained by the L. fuscana larva showed a decreasing trend with the age. On the basis of the results, it is apparent that the larva of the mosquito L. fuscana can be used in the regulation of the mosquito A. aegypti through augmentative release, particularly, in the smaller mosquito larval habitats.

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Santos Silva-Filho, Edivaldo, Talita Guimarães Araújo-Piovezan, José Oliveira Dantas, Maria de Jesus Silvestre, Agripino Emanuel de Oliveira Alves e Genésio Tâmara Ribeiro. "Controle de Larvas de Aedes aegypti por Ninfas de libélula (Odonata) sob Condições Laboratoriais". Ensaios e Ciência C Biológicas Agrárias e da Saúde 25, n. 2 (29 giugno 2021): 239–42. http://dx.doi.org/10.17921/1415-6938.2021v25n2p239-242.

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Abstract (sommario):

Estudos para o combate ao vetor Aedes aegypti são importantes para reduzir as incidências da Dengue, Zika e Chikungunya, responsáveis por milhares de mortes no Mundo. Este estudo hipotetiza que as ninfas de odonata influenciam no controle de larvas de Aedes aegypti com eficácia diferente entre as famílias, por terem distinta morfologia de aparelho mastigador e comportamento. O objetivo com esta pesquisa foi avaliar a eficiência de sete famílias de odonata como predadoras de Aedes aegypti, em condições laboratoriais. Ninfas foram coletadas com armadilha de rede, no Rio Poxim Açu e individualizadas, em potes plásticos, com 20 cm de diâmetro, contendo água do rio e mantidas em temperatura ambiente. Para verificar a potencialidade de predação de larva de Aedes aegypti, pelas ninfas de Odonata, tendo sido avaliada a taxa de predação de 30 larvas de mosquito, em cada pote por dia, contabilizando-se o número de larvas predadas. A média de predação pelas ninfas foi de 6,08 larvas de mosquito por dia. As famílias Aeshnidae (9,28), Libellulidae (8,37) obtiveram as maiores médias de predação por dia. Todas as famílias de odonata predaram, em pelo menos um dia, o máximo de 25 a 30 larvas, exceto Cordulidae. Portanto, os predadores da família Aeshnidae e Libellulidae foram muito eficazes no controle do Aedes aegypti e representam uma alternativa de baixo custo e de fácil aplicabilidade em cisternas e caixas de água domiciliares, que têm condições semelhantes às encontradas neste experimento. Palavras-chave: Agentes de Controle Biológico. Dengue. Vírus Zika.Vírus Chikungunya. Abstract Studies of Aedes aegypti control are especially important for reducing the incidence of Dengue, Zika and Chikungunya cases that are responsible for thousands of human deaths in the world. This study hypothesizes that odonata nymphs influence the Aedes aegypti larvae control with different efficacy among their families, due to their chewing apparatus morphology and to their diverse behavior in nature. The objective was to evaluate the efficiency of seven families of odonata nymphs as predators of the Aedes aegypti larvae under laboratory conditions. Odonata nymphs of seven families were collected with a net trap at Poxim Açu River. Each nymph was placed in a 20-cm diameter plastic recipient containing river water at room temperature. In order to verify the odonata nymphs predation on the Aedes aegypti larvae, the predation rate of 30 mosquito larvae was verified on each recipient per day. The odonata nymphs presented an average predation rate of 6.08 mosquito larvae per day. The families Aeshnidae (9,28) and Libellulidae (8,37) obtained the greatest average predation rate per day. All the Odonata families predated from 25 to 30 larvae in at least one day, except Cordulidae. Therefore, the Ashinadae and libelulidae predators were highly effective on the Aedes aegypti control. Thus, they represent a low-cost alternative for Aedes control in cisterns and water tanks at home sites, which have similar conditions to the ones found in this experiment. Keywords: Biological Control Agents. Dengue Virus. Zika Virus. Chikungunya Virus.

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16

Blodgett, Sue L., Andrew W. Lenssen e S. Dennis Cash. "Harvest with Raking for Control of Alfalfa Weevil (Coleoptera: Curculionidae)". Journal of Entomological Science 35, n. 2 (1 aprile 2000): 129–35. http://dx.doi.org/10.18474/0749-8004-35.2.129.

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Abstract (sommario):

Successful implementation of early harvest techniques for alfalfa weevil larval, Hypera postica Gyllenhal, management depends on synchronization between alfalfa growth sufficient for harvest and economic populations of the insect, conditions that frequently occur in Montana. Field trials were conducted in 1996 and 1997 to determine if the addition of raking to timed harvest would improve the efficacy of alfalfa weevil larvae management, an important cultural control of alfalfa weevil larval populations. Post-baling mean number of alfalfa weevil larvae in stubble were 4.3 (SE = 1.6) and 7.5 (SE = 1.1) per 0.1 m2 for cutting with raking and cutting alone, respectively, (P = 0.06). Nutritive value of forage, as estimated by crude protein and neutral and acid detergent fiber concentrations, did not differ between treatments. Harvest combined with early raking effectively reduced alfalfa weevil larvae populations over cutting alone without compromising nutritive value of forage.

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Pepperný, K. "Influence of baculovirus AdorGV on the mortality of larvae and pupae of summer fruit tortrix Adoxophyes orana in laboratory conditions". Plant Protection Science 43, No. 3 (7 gennaio 2008): 94–102. http://dx.doi.org/10.17221/2245-pps.

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Abstract (sommario):

The mortality of larvae and pupae of Adoxophyes orana was examined by keeping larvae of each larval instar (L1–L5) on an artificial diet in laboratory conditions. Larvae were infected by using an artificial diet containing AdorGV-based CAPEX® 2. Samples of uninfected larvae from each instar served as controls. The mortality of larvae infected in the 1st instar was 100%, compared to a mortality of 68% in the control. In both, the larvae died before the 5th larval instar. With larvae infected in subsequent instars the mortality rate declined gradually (96%–72%–40%–12%) and death occurred predominantly in the 5th larval instar. The mortality of larvae in the controls was low (12%–12%–0%–0%). The mortality of pupae from larvae infected in the 2nd, 3rd and 4th instar was high (100%–86%–93%), and the mortality of larvae and pupae combined was close to 100%. Mortality of pupae developed from larvae infected in the 5th instar was 27% and that of larvae and pupae combined was 36%. The mortality of pupae developed from uninfected larvae in all controls was low (max. 8%). These results demonstrated the high efficacy of AdorGV to cause high mortality of larvae and pupae of Adoxophyes orana in laboratory conditions.

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Panigrahi, Bivas, e Chia-Yuan Chen. "Microfluidic Transportation Control of Larval Zebrafish through Optomotor Regulations under a Pressure-Driven Flow". Micromachines 10, n. 12 (14 dicembre 2019): 880. http://dx.doi.org/10.3390/mi10120880.

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Abstract (sommario):

To perform zebrafish larvae-related experiments within a microfluidic environment, the larvae need to be anesthetized and subsequently transported into respective test sections through mechanical or manual means. However, anesthetization tends to affect larval sensory perceptions, hindering their natural behaviors. Taking into account that juvenile larvae move naturally within their environment by accessing visual as well as hydromechanical cues, this work proposes an experimental framework to transport nonanesthetized larvae within a microfluidic environment by harmonically tuning both of the aforementioned cues. To provide visual cues, computer-animated moving gratings were provided through an in-house-developed control interface that drove the larval optomotor response. In the meantime, to provide hydromechanical cues, the flow rate was tuned using a syringe pump that affected the zebrafish larvae’s lateral line movement. The results obtained (corresponding to different test conditions) suggest that the magnitude of both modalities plays a crucial role in larval transportation and orientation control. For instance, with a flow rate tuning of 0.1 mL/min along with grating parameters of 1 Hz temporal frequency, the average transportation time for larvae that were 5 days postfertilization was recorded at 1.29 ± 0.49 s, which was approximately three times faster than the transportation time required only in the presence of hydromechanical cues.

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19

Hidayati, Lisa, e Seli Suprihatini. "Pengaruh Pemberian Ekstrak Biji Mahoni (Swietenia mahagoni) Terhadap Kematian Larva Culex sp". ASPIRATOR - Journal of Vector-borne Disease Studies 12, n. 1 (29 giugno 2020): 45–52. http://dx.doi.org/10.22435/asp.v12i1.2171.

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Abstract (sommario):

Abstract. Mahogany seed extract (Swietenia mahagoni) is a natural larvacidal material which contains limonoid, flavonoid, saponins and alkoloid. Mahogany seed extract can kill Culex sp larvae, which known as filariasis vectors. There are several mosquitoes control are used to pressing Culex sp larvae growth, such as using larvacidal and fogging but have bad impact on the circumtances The study observed effect of mahogany seed extract on Culex sp. larvae mortality. This study utilized an experimental method with ANOVA and probit analysis to determined LC50 and LT50. Extraction method were used in this study was maceration method. This research used some variation of mahogany seed extract concentration, consist of 8%, 10%, 20%, 50%, with negative control (-) used distilled water. Research repetition was carried out 3 times with a total sample of 325 larvae. Observations were made at 15, 60, 120, 240, 420 and 720 minutes (12 hours). This study found that there was a significant effect between the concentration of mahogany seed extract on larval mortality with Fcount > Ftable (0.05 ≥ 0.01). The concentration that effectively kills 50% of Culex sp (LC50) larvae was 10%. the time which was needed to kill 50% of Culex sp (LT50) larvae was 204,230 minutes. The higher the concentration level of mahogany seed extract were used, so that more larval mortality rates. The morphology or larvae body structure after administration of mahogany seed extract was damaging in the abdomen and thorax, allegedly inhibited growth hormone due to the mechanism of action of mahogany seed extract as an antifeedant This reaserch can be using mahogany seed extract with different methods and larvae. Mahogany seed extracts are expected to be applied in society as a vector control and this research can be developed using mahogany seed extract with different methods and larvae. Keywords: Mahogany seeds, Extract, Culex sp, larvacidal, Maceration, Abstrak. Ekstrak biji mahoni (Swietenia mahagoni) merupakan bahan larvasida alami yang mengandung limonoid, flavonoid, saponin dan alkoloid. Ekstrak biji mahoni diduga bisa membunuh larva Culex sp, yang berperan sebagai vektor filariasis. Ada beberapa cara penanggulangan nyamuk yang digunakan untuk menekan pertumbuhan larva Culex sp, seperti penggunaan larvasida dan fogging tetapi memiliki dampak yang buruk untuk lingkungan. Tujuan dari penelitian ini untuk melihat pengaruh ekstrak biji mahoni terhadap kematian larva Culex sp. Penelitian ini menggunakan metode eksperimental dengan analisis ANOVA dan analisis probit untuk menentukan LC50 dan LT50 . Metode ekstraksi yang digunakan dalam penelitian ini adalah modifikasi maserasi. Konsentrasi ekstrak biji mahoni yang diujikan yaitu 8%, 10%, 20%, 50%, dengan kontrol (-) menggunakan aquadest. Pengulangan dilakukan sebanyak 3 kali dengan total sampel 325 larva. Pengamatan dilakukan pada menit ke 15, 60, 120, 240, 420 dan 720 menit (12 jam). Penelitian ini memperoleh hasil bahwa adanya pengaruh yang signifikan antara konsentrasi ekstrak biji mahoni terhadap kematian larva dengan Fhitung > Ftabel (0,05 ≥ 0.01). Konsentrasi yang efektif membunuh 50% larva Culex sp (LC50) adalah 10%. waktu yang dibutuhkan untuk membunuh 50% larva Culex sp(LT50 ) adalah 204,230 menit. Semakin tinggi tingkat konsentrasi ekstrak biji mahoni semakin tinggi pula tingkat kematian larva. Morfologi atau struktur tubuh larva setelah pemberian ekstrak biji mahoni mengalami kerusakan di bagian abdomen dan toraks, diduga mengalami penghambatan hormonpertumbuhan karena mekanisme kerja ekstrak biji mahoni sebagai antifeedant. Ekstrak biji mahoni diharapkan dapat diaplikasikan di dalam masyarakat sebagai pengendalian vector dan Penelitian ini bisa dikembangkan dengan menggunakan ekstrak biji mahoni dengan metode dan larva yang berbeda. Kata Kunci: Biji mahoni, Ekstrak, Culex sp, Larvasida, Maserasi

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20

Cranshaw, Whitney, e Thomas B. Eckberg. "Comparison of two Neem Insecticides for Fall Webworm Control, Laboratory Bioassay 1992". Arthropod Management Tests 20, n. 1 (1 gennaio 1995): 328. http://dx.doi.org/10.1093/amt/20.1.328.

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Abstract Field collected late instar fall webworm larvae were divided into groups of ten and placed in petri dishes. Six groups (60 larvae) were used in each treatment. Chokecherry foliage was treated by dipping in the various solutions tested and allowing to air dry. On August 6, the larvae were fed the treated foliage for the first 3 days, and subsequently fed untreated foliage for the duration of the experiment. Larval mortality was assessed on August 10 (4 DAT), August 13 (7 DAT), and August 17 (11 DAT).

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21

Chamberlin, M. E. "Control of oxidative phosphorylation during insect metamorphosis". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 287, n. 2 (agosto 2004): R314—R321. http://dx.doi.org/10.1152/ajpregu.00144.2004.

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Abstract (sommario):

The midgut of the tobacco hornworm ( Manduca sexta) is a highly aerobic tissue that is destroyed and replaced by a pupal epithelium at metamorphosis. To determine how oxidative phosphorylation is altered during the programmed death of the larval cells, top-down control analysis was performed on mitochondria isolated from the midguts of larvae before and after the commitment to pupation. Oxygen consumption and protonmotive force (measured as membrane potential in the presence of nigericin) were monitored to determine the kinetic responses of the substrate oxidation system, proton leak, and phosphorylation system to changes in the membrane potential. Mitochondria from precommitment larvae have higher respiration rates than those from postcommitment larvae. State 4 respiration is controlled by the proton leak and the substrate oxidation system. In state 3, the substrate oxidation system exerted 90% of the control over respiration, and this high level of control did not change with development. Elasticity analysis, however, revealed that, after commitment, the activity of the substrate oxidation system falls. This decline may be due, in part, to a loss of cytochrome c from the mitochondria. There are no differences in the kinetics of the phosphorylation system, indicating that neither the F1F0 ATP synthase nor the adenine nucleotide translocase is affected in the early stages of metamorphosis. An increase in proton conductance was observed in mitochondria isolated from postcommitment larvae, indicating that membrane area, lipid composition, or proton-conducting proteins may be altered during the early stages of the programmed cell death of the larval epithelium.

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22

Chil-Núñez, Idelsy, Paloma Martins Mendonça, Julio C. Escalona-Arranz, Carlos M. Dutok-Sánchez, Frenkel Guisado Bourzac e Margareth M. de Carvalho Queiroz. "Larvicide and insecticide activity of the essential oil of Ocimum sanctum var. cubensis in the control of Musca domestica (Linnaeus, 1758), under laboratory conditions". Revista Amazonia Investiga 9, n. 34 (23 novembre 2020): 24–33. http://dx.doi.org/10.34069/ai/2020.34.10.3.

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Abstract (sommario):

Essential oils have been considered as an important alternative facing synthetic pesticides. The control of the species Musca domestica is very important for public health due to their role as vector associated with Vibrio cholerae, Salmonella and Shigella, among other pathogens. The objective of this work was to evaluate the larvicidal and insecticidal efficacy of the essential oil of Ocimum sanctum var. cubensis, in the control of Musca domestica and its effect on the post-embryonic development of this species. The essential oil was applied topically in six concentrations to newly hatched larvae (1μL / larva). Mortality, interval length of each development period, as well as the weight of mature larvae were analyzed. An insecticidal bioassay was also carried out in adult flies. The essential oil of O. sanctum caused a slight reduction in the larval and pupal period for some of the concentrations evaluated. The time of development of the newly hatched larvae until the adult period was shortened in all the concentrations analyzed. The larvae of the control group were the heaviest. The effectiveness of the product in the control of the larvae of the flies of the species M. domestica was greater than 50%, except for those larvae treated with 80.25 mg/mL of the essential oil. The lethal concentration for adult insects LC50 was estimated at 9.41μg. Results demonstrated that the essential oil of O. sanctum has effect in all stages of the life cycle of M. domestica, extolling its potential as an effective insecticide against this species.

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23

Pellegrini, María C., Lucía Zalazar, Sandra R. Fuselli e Alejandra G. Ponce. "Inhibitory action of essential oils against proteases activity of Paenibacillus larvae, the etiological agent of American Foulbrood disease". Spanish Journal of Agricultural Research 15, n. 4 (7 febbraio 2018): e0504. http://dx.doi.org/10.5424/sjar/2017154-10785.

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Abstract (sommario):

American foulbrood (AFB) is a disease affecting the larva of Apis mellifera. The etiological agent is Paenibacillus larvae, which releases metalloproteases involved in the degradation of larval tissues. Through quorum sensing (QS) mechanism, bacteria are able to activate specific genes such as virulence factors. The exoproteases regulation of P. larvae could be associated with QS. A promising mechanism of AFB control is to block QS mechanism with essential oils (EO). The aim of this study was to investigate the potential presence of QS signals in the regulation of P. larvae proteases and the effect of seven EOs on the exoproteases activity of P. larvae. From growth curves and evaluation of the presence of proteases by milk agar plates assay, it was observed protease activity during the late exponential phase of growth. Early production of protease activity (15 hours earlier than control) was observed when a low density culture was incubated with late exponential spent medium (SM) suggesting the presence of factor(s) inducing this activity. SM was obtained by the ultrafiltration of P. larvae cultures on late growth phase and was free of proteases. Proteolytic activity was quantified on P. larvae cultures in presence of sublethal concentration of EO by azocasein method. The EOs, except S. chilensis EO, reduced significantly protease activity (more than 50%). We report for the first time evidence on the possible role of QS on P. larvae and the antiproteolytic activity of EOs (except for S. chilensis) on exoproteases, an interesting therapeutic strategy to control AFB.

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24

Prabowo, Heri, e I. G. A. A. Indrayani. "Keefektifan Nematoda Patogen Serangga Steinernema sp. Terhadap Achaea janata L., Serangga Pemakan Daun Jarak Kepyar (Ricinus communis)". Buletin Tanaman Tembakau, Serat & Minyak Industri 5, n. 2 (10 ottobre 2016): 58. http://dx.doi.org/10.21082/bultas.v5n2.2013.58-68.

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Abstract (sommario):

Penggunaan pestisida kimia yang cukup tinggi pada akhir-akhir ini telah menimbulkan dampak negatif ter-hadap lingkungan, sehingga pengendalian hama yang ramah lingkungan sangat diperlukan. Saat ini, peng-gunaan nematoda entomopatogen terutama Steinernema sp., membuka peluang untuk digunakan sebagai pengendalian Achaea janata. Tujuan dari penelitian ini untuk mengetahui keefektifan Steinernema sp. ter-hadap A. Janata , dilaksanakan di laboratorium patologi serangga Balai Penelitan Tanaman Pemanis dan Serat pada bulan Maret sampai dengan Agustus 2011. Penelitian menggunakan rancanagan acak lengkap (RAL) dengan empat ulangan. Setiap ulangan menggunakan 25 larva A. janata instar 2. Larva diekspose de-ngan berbagai variasi konsentrasi Steinernema sp. dan kematian larva diamati setiap hari sampai 120 jam setelah infeksi. Konsentrasi Steinernema sp. yang digunakan adalah 0, 50, 100, 200, 300, dan 400 JI/larva. Hasil penelitian pemberian Steinernema sp. pada konsentrasi 200, 300, dan 400 JI/larva cukup efektif untuk membunuh A. janata dengan persentase berkisar antara 80–94% mulai 48–120 jam setelah perlakuan. Se-makin tinggi konsentrasi nematoda, semakin tinggi mortalitas A. janata. Steinernema sp. dengan konsen-trasi 400 JI/larva paling efektif membunuh larva, menurunkan bobot larva, bobot pupa, jumlah telur yang dihasilkan, dan fertilitas telur. High intensity of chemical pesticide application has become a serious concern of environmentalists in recent years, because of various negative impacts of it. Therefore, environmentally friendly techniques of controlling insect pest are needed. Recently, the use of entomopathogenic nematodes, especially Steinernema sp., has created new possibilities of promising control techniques against insect pests. The aim of this study was to evaluate the effectiveness of Steinernema sp. to A. janata larvae in laboratory. This research was conducted at the Laboratory of Insect Pathology Laboratory of Indonesian Sweetener and Fiber Crops Research Insti-tute from March to August 2011. Tests used the 2nd stage larvae of Achaea janata, the leaf eater of castor (Ricinus communis). Treatment arranged in a completely randomized design (CRD) with 4 replicates. For each test used 25 larvae which were exposed to various concentrations of Steinernema sp. Concentration of Steinernema sp. used was 0, 50, 100, 200, 300, and 400 infective juvenile/larvae. Daily mortality A. janata larvae, larval and pupal weight, the number of eggs laid, and number of hatch eggs were recorded. Steinernema sp. on concentration of 200; 300; and 400 IJ/larvae was effective to cause mortality of A. janata larvae (80–94% mortality after 48–120 hours). The higher the concentration of the nematode the higher larval mortality. Steinernema sp. with concentration of 400 IJ/ larvae was effective decreasing larval and pupal weight, the number of eggs laid, and fertility of the eggs produced.

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Saunders, L. M., D. M. Tompkins e P. J. Hudson. "The dynamics of nematode transmission in the red grouse (Lagopus lagopus scoticus) : studies on the recovery of Trichostrongylus tenuis larvae from vegetation". Journal of Helminthology 73, n. 2 (febbraio 1999): 171–75. http://dx.doi.org/10.1017/s0022149x99000268.

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Abstract (sommario):

Attempts to recover the infective third-stage larvae of Trichostrongylus tenuis from heather (Calluna vulgaris) vegetation in the field are rarely successful because the larvae may be: (i) concealed within heather leaflets; (ii) concentrated in dew droplets which are lost from the plants upon sampling; or (iii) simply highly aggregated in the field. Heather plants were exposed to T. tenuis larvae in the laboratory and kept under suitable conditions for larval migration. Few larvae were found in dew droplets or concealed within heather leaflets; most larvae were recovered from the plant surface. This suggests that the low larval recovery from vegetation in the field simply reflects a highly aggregated distribution of few larvae. In a second experiment, the efficiency with which infective larvae migrate up the structurally complex heather plants was compared with migration up two control plant species with simpler structures: a monocotyledon, wheat, and a dicotyledon, hebe. After constant exposure, significantly more larvae were recovered from heather than from either of the control plants. This implies that the structural complexity of heather causes no problems for the infective larvae.

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26

Gao, Shang-kun, Cui-cui Geng, Ying-chao Ji, Zi-kun Li e Cheng-gang Zhou. "Density-Dependent Growth and Fitness in Dastarcus helophoroides (Coleoptera: Bothrideridae)". Insects 10, n. 11 (4 novembre 2019): 386. http://dx.doi.org/10.3390/insects10110386.

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Abstract (sommario):

The ectoparasitoid Dastarcus helophoroides Fairmaire (Coleoptera: Bothrideridae) is an important natural enemy insect, which is artificially mass-reared and released into woodland to control medium and large longhorn beetle species. This study examined the developmental duration (days) of larvae and adult fitness (including numbers of adults emerging per host and mean body size) by exposing a single substitute host, a pupa of Zophobas morio (Coleoptera: Tenebrionidae), to different densities of D. helophoroides larvae. We showed that there was no significant effect on the rate of successful parasitism and cocoon formation, but emergence success and measures of individual adult body size (length, width, and weight) declined with increasing larval density. Larval period and cocoon period increased with larval density, while total weight of adults emerging per host increased initially before reaching a plateau. Our results suggest that a pupa of Z. morio could be successfully parasitized by a single D. helophoroides larva, but multiple D. helophoroides larvae can share one host. Excessive larval density caused intraspecific competition among D. helophoroides larvae, manifesting in extended developmental duration of immature stage and reduced fitness of adults. Furthermore, the tradeoff between the numbers of adults and body size may stabilize the population dynamics with detectable mutual interference, particularly in competing for limited host resources. These findings suggest six larvae per host would achieve the highest adult fitness and would enhance mass-rearing techniques as part of IPM strategies for longhorn beetles.

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Nale, Janet Y., Mahananda Chutia, Jeffrey K. J. Cheng e Martha R. J. Clokie. "Refining the Galleria mellonella Model by Using Stress Marker Genes to Assess Clostridioides difficile Infection and Recuperation during Phage Therapy". Microorganisms 8, n. 9 (27 agosto 2020): 1306. http://dx.doi.org/10.3390/microorganisms8091306.

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Abstract (sommario):

The Galleria mellonella is an effective model for probing Clostridioides difficile interactions with phages. Despite valuable insights from this model, the larvae are not easily amenable to assessing detailed clinical responses to either bacteria or phages. Here, larval survival, colonisation and toxin levels were compared to expression profiles of 17 G. mellonella stress genes to monitor Clostridiodes difficile infection (CDI), and recuperation during phage therapy. The larvae were infected with a ribotype 014/020 isolate and treated with an optimised phage cocktail. Larvae treated prophylactically with phages and the phage-control larval group were protected, showing the highest survival, and low C. difficile colonisation and toxin rates, compared to co-infection, remedial and bacterial-control larval groups. Expression of growth (9) and reproduction (2) genes were enhanced within prophylaxis and phage-control larval groups compared to the co-infection, remedial and bacterial control groups. In contrast, expression of infection (2), humoral (1) and cellular (3) immunity genes declined in the prophylactic and phage-control groups but increased in the co-infection, remedial and bacterial control larvae. The molecular markers augment the survival, colonisation and toxin data and allow detailed monitoring of CDI and recovery. This data support the use of stress marker genes as tools to analyse clinical symptoms in this model.

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Marini, Marini, Vivin Mahdalena e Tanwirotun Ni'mah. "Potensi Ekstrak Daun Marigold (Tagetes erecta L.) sebagai Larvasida terhadap Larva Aedes aegypti di Laboratorium". Jurnal Vektor Penyakit 12, n. 2 (17 dicembre 2018): 109–14. http://dx.doi.org/10.22435/vektorp.v12i2.898.

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Abstract Control of mosquito vectors by using natural ingredients is being developed intensively. Marigold (Tagetes erecta) was widely used as a mosquito repellent plant. The results of research before had found that marigold leaf extract has a repulsive effect on Aedes aegypti mosquitoes. This study aimed to identify the potential of marigold leaf extract as larvacide against Ae. aegypti larvae in the laboratory. The material used in this research was extracts of marigold leaves. Larvacide test was carried out by dissolving of extract in water at the concentration of 2,000 ppm, 4,000 ppm, 6,000 ppm, 8,000 ppm, and 10,000 ppm. The larvae used was Ae. aegypti larvae as many as 25 larvae each five treatment of replications. Probit analysis was conducted on larval mortality after 24 hours of exposure. The results of the probit analysis showed that the estimated concentration of extracts that could result in larval mortality up to 95% (LC95) was 7,456 ppm. From the result we can conclude that ethanol extract of marigold leaves (T. erecta L. ) has the biolarvacidal activity against larvae. Abstrak Pengendalian vektor nyamuk dengan memanfaatkan bahan alam makin banyak dikembangkan. Marigold (T. erecta) merupakan tumbuhan yang banyak dimanfaatkan sebagai tanaman pengusir nyamuk. Hasil penelitian sebelumnya menemukan bahwa ekstrak daun memiliki daya tolak terhadap nyamuk Ae. aegypti. Penelitian ini bertujuan untuk melihat potensi ekstrak daun marigold sebagai larvasida terhadap larva Ae. aegypti instar III di laboratorium. Bahan yang digunakan pada penelitian ini adalah ekstrak etanol daun marigold hasil ekstraksi dari penelitian sebelumnya. Uji larvasida dilakukan dengan melarutkan ekstrak dalam air pada konsentrasi 2.000 ppm, 4.000 ppm, 6.000 ppm, 8.000 ppm, dan 10.000 ppm. Larva yang digunakan yaitu larva Ae. aegypti sebanyak 25 larva tiap perlakuan dengan lima ulangan. Dilakukan analisis probit terhadap kematian larva setelah 24 jam paparan. Hasil analisa probit menunjukkan perkiraan konsentrasi ekstrak yang mampu mengakibatkan kematian larva hingga 95% (LC95 ) adalah 7.456 ppm. Ekstrak etanol daun marigold (T.erecta L.) memiliki potensi sebagai biolarvasida terhadap larva Ae. aegypti.

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29

Treviño-Cueto, Diego, Sergei A. Subbotin e Sergio R. Sanchez-Peña. "Larvicidal Activity of Entomopathogenic Nematodes Isolated from Mexico against Aedes aegypti (Diptera: Culicidae)". Journal of Entomological Science 56, n. 1 (1 gennaio 2021): 12–23. http://dx.doi.org/10.18474/0749-8004-56.1.12.

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Abstract Entomopathogenic nematodes (EPNs) are widely used agents of biological control, mainly targeting soil-inhabiting insect pests. Reports indicate that these terrestrial EPNs are also able to infect the aquatic larvae of mosquitoes. We isolated EPN strains (Heterorhabditis bacteriophora Poinar and Steinernema carpocapsae [Weiser]) from local soils at Saltillo, Coahuila state, Mexico. EPNs from these strains were produced in the laboratory in yellow mealworm (Tenebrio molitor L.) larvae, and their pathogenicity as infective juveniles (IJs) was tested against larvae of the yellow fever mosquito Aedes aegypti (L.) Third- and fourth-instar mosquito larvae were exposed to four concentrations of IJs (25, 50, 100, and 200 IJ/larva) of five strains of local EPNs in laboratory assays. All strains of EPN caused lethal infections in larvae (3–100%); in particular, strain M5 of S. carpocapsae caused 100% mortality at the 200 IJ/larva concentration, with a median lethal concentration (LC50) of 42 IJ/larva (LC90 = 91 IJ/larva). Strain M18 of H. bacteriophora caused 73% mortality at 200 IJ/larva, with an LC50 = 72 and LC90 = 319 IJ/larva. IJs were produced by all strains in mosquito larvae, with a range of 66–239 IJ/mosquito larva (inoculated at 100 IJ/larva) across strains, suggesting that horizontal transmission might occur in the field. This represents the first report of native EPN strains from Mexico exhibiting pathogenicity against mosquito larvae. Native EPN strains should be further evaluated as potential biological control agents in mosquito management.

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30

Eba, Kasahun, Luc Duchateau, Beekam Kebede Olkeba, Pieter Boets, Dechasa Bedada, Peter L. M. Goethals, Seid Tiku Mereta e Delenasaw Yewhalaw. "Bio-Control of Anopheles Mosquito Larvae Using Invertebrate Predators to Support Human Health Programs in Ethiopia". International Journal of Environmental Research and Public Health 18, n. 4 (12 febbraio 2021): 1810. http://dx.doi.org/10.3390/ijerph18041810.

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Mosquitoes have been a nuisance and health threat to humans for centuries due to their ability to transmit different infectious diseases. Biological control methods have emerged as an alternative or complementary approach to contain vector populations in light of the current spread of insecticide resistance in mosquitoes. Thus, this study aimed to evaluate the predation efficacy of selected potential predators against Anopheles mosquito larvae. Potential invertebrate predators and Anopheles larvae were collected from natural habitats, mainly (temporary) wetlands and ponds in southwest Ethiopia and experiments were conducted under laboratory conditions. Optimal predation conditions with respect to larval instar, water volume and number of predators were determined for each of the seven studied predators. Data analyses were carried out using the Poisson regression model using one way ANOVA at the 5% significant level. The backswimmer (Notonectidae) was the most aggressive predator on Anopheles mosquito larvae with a daily mean predation of 71.5 larvae (95% CI: [65.04;78.59]). Our study shows that larval instar, water volume and number of predators have a significant effect on each predator, except for dragonflies (Libellulidae), with regard to the preference of the larval instar. A selection of mosquito predators has the potential to control Anopheles mosquito larvae, suggesting that they can be used as complementary approach in an integrated malaria vector control strategy.

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31

Iwan, Suryadi. "Habitat characteristics with an. barbirostris larva density in Bulukumba". E3S Web of Conferences 73 (2018): 06019. http://dx.doi.org/10.1051/e3sconf/20187306019.

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Bulukumba is a malaria endemic area in South Sulawesi with malaria cases reported annually, An.barbirostris as a potential vector of malaria in the area. This study aims to analyze habitat characteristics with a density of An. barbirostris larvae The method used is an observational study with ecological survey design through the cross-sectional approach of samples in the form of Anopheles larvae habitat. Bivariate analysis shows physical, chemical, and biological environmental factors. water temperature significant to the density of larva An.barbirostris with p-value = 0,002. Multivariate test using linear regression to know the most influential variables, it is known that the variables that have the most influence on the density of larvae An. barbirostris in endemic area Bulukumba is water temperature p = 0,002. Environmental factors such as salinity, aquatic plant, plants around, predators and crops along with water temperature are factors that support the density of An. barbirostris larvae Control can be done with environmental management, especially interventions on Anopheles sp larvae breeding habitat, by sowing predator fish seeds, habitat modification and manipulation. modification of anopheles habitat by covering habitats and carrying out development can reduce larval nutrition so as to reduce carbon in the soil which results in a decrease in larval density.

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32

Tzaneva, Velislava, e Steve F. Perry. "Role of endogenous carbon monoxide in the control of breathing in zebrafish (Danio rerio)". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 311, n. 6 (1 dicembre 2016): R1262—R1270. http://dx.doi.org/10.1152/ajpregu.00094.2016.

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Carbon monoxide (CO) is a gaseous signaling molecule and is produced in vivo from the intracellular breakdown of heme via the heme oxygenase (HO) family of enzymes. In this study we investigated the role of the HO-1/CO system in the control of ventilation in zebrafish, Danio rerio. Immunohistochemistry revealed the presence of HO-1 in the chemoreceptive neuroepithelial cells (NECs) of larvae (4 days postfertilization) and adults, indicating the potential for endogenous CO production in the NECs. Hypoxia (20 min, water Po2 of 30 mmHg) caused a significant increase in HO-1 activity in whole larvae and in the gills of adult fish. Zebrafish with reduced HO-1 activity (via HO-1 knockdown in larvae or zinc protoporphyrin IX treatment in adults) exhibited increased ventilation frequency ( Vf) under normoxic but not hypoxic conditions. The addition of exogenous CO restored resting Vf in fish with diminished CO production, and in some cases (e.g., hypoxic sham larvae) CO modestly reduced Vf below resting levels. Larval fish were treated with phenylhydrazine (PHZ) to eliminate the potential confounding effects of CO-hemoglobin interactions that might influence ventilation. PHZ treatment did not cause changes in Vf of normoxic larvae, and the addition of CO to PHZ-exposed larvae resulted in a significant decrease in sham and HO-1-deficient fish under normoxic conditions. This study demonstrates for the first time that CO plays an inhibitory role in the control of breathing in larval and adult zebrafish.

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33

Ashfaq, Muhammad, S. Y. Young e R. W. McNew. "Bollworm (Lepidoptera: Noctuidae) Development and Movement on Bacillus thuringiensis-treated Cotton Leaves". Journal of Entomological Science 36, n. 1 (1 gennaio 2001): 23–33. http://dx.doi.org/10.18474/0749-8004-36.1.23.

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Larval mortality, survivorship and movement of the bollworm, Helicoverpa zea (Boddie), on and away from Bacillus thuringiensis-treated cotton leaves were investigated in the laboratory. Bacillus thuringiensis (Costar®, Novartis Crop Protection, Inc; Greensboro, NC) was applied to the upper surface of cotton leaves via a spray table in five concentrations, i.e., 0.0 (control), 0.14, 0.29, 0.58, and 1.15 kg/ha. Three-day-old H. zea larvae were released on treated leaves, kept at 30°C, and transferred to artificial diet after 12, 24, and 48 h. Significantly higher numbers of larvae were found on the lower than upper leaf surface after all three transfer times, but the numbers surviving in all treatments were similar to the control. Larval movement from the leaf to cup surface was significantly higher in B. thuringiensis-treated leaves than in the control. The mortality of larvae that were transferred from leaves to diet at 7 d after treatment was significantly higher in all treatments than in the control and highest at the highest rates (0.58 and 1.15 kg/ha). Data on survival of larvae at different locations suggest that for the first 24 h, the increase in the percentage of larvae on the inner cup surface in B. thuringiensis treatments was not due to larvae that had consumed a lethal dose, but an attempt to avoid the B. thuringiensis on the upper leaf surface. Highest larval weight was recorded in the control for all transfer times. The length of the larval period increased with the B. thuringiensis rate at the 12-h transfer. The pupal weight was reduced at the highest B. thuringiensis rates at the 48-h transfer.

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34

Bagatto, B., B. Pelster e W. W. Burggren. "Growth and metabolism of larval zebrafish: effects of swim training". Journal of Experimental Biology 204, n. 24 (15 dicembre 2001): 4335–43. http://dx.doi.org/10.1242/jeb.204.24.4335.

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SUMMARY Larval zebrafish (Danio rerio) of three different age classes (‘yolk-sac’ larvae, 96 h; ‘swim-up’ larvae, 9 days old; and ‘free-swimming’ larvae, 21 days old) were trained for 2, 6 and 11 days, respectively, to swim at 0 body lengths per second (BL s–1), 2 BL s–1 and 5 BL s–1. Survival was significantly diminished in larvae trained at 5 BL s–1 compared to controls (0 BL s–1). Although training produced no significant differences in mass and length, the youngest larvae absorbed their yolk at a faster rate during training. Routine oxygen consumption (ṀO2r) and mass-specific routine oxygen consumption (ṀO2r,m) were not significantly affected by chronic training in the yolk-sac larvae and swim-up larvae. However, trained free-swimming larvae had a significantly higher ṀO2r (after 11 days of training) and ṀO2r,m (after 8 and 11 days of training) compared to control larvae. Trained free-swimming larvae consumed significantly less oxygen during swimming compared to control larvae, as measured by closed-system respirometry. Trained yolk-sac larvae exposed to increasing hypoxia levels were more effective O2 regulators. Additionally, training enhanced survival during exposure to extreme hypoxia in all age groups. Thus, physiological acclimation to chronic swimming occurs in the earliest stages of life in the zebrafish.

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35

Parker, Paul E. "Nematode Control of Silverleaf Nightshade (Solanum elaeagnifolium); a Biological Control Pilot Project". Weed Science 34, S1 (1986): 33–34. http://dx.doi.org/10.1017/s0043174500068351.

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The use of nematodes as biological control agents has been met with skepticism, partly due to the newness of the approach and also to the potential difficulties of using a parasitic worm as a control organism. Most of the attention directed towards nematodes as biological control agents has been focused on several species that act as insect parasites. Considerable headway has been achieved with several of these parasites, especially with those parasitic on wood-boring insect larvae. The insect gallery of wood-boring larvae provides an optimum microclimate for the nematode to survive and seek out its larval insect host. A system where this strategy has proved successful involves the use of the insect parasitic nematodeNeoaplectana carpocapsaeWeiser as a biological control agent for carpenterworms (Prionoxystus robinaePeck) in fig (Ficus cariaL.) orchards in California (6). Similar systems are being developed both here and abroad with the same nematode or a closely related genus or species. Many of these systems show promise (5).

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36

Nasir, M., K. Sumawidjaja, K. Sumawidjaja e Irzal Effendi. "Control of Natural Food with Diazinon for Growth and Survival of Marbled Goby, Oxyeleotris marmorata (Bleeker)". Jurnal Akuakultur Indonesia 3, n. 2 (1 agosto 2007): 19. http://dx.doi.org/10.19027/jai.3.19-24.

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Dua percobaan telah dilakukan, yaitu tanpa dan dengan larva ikan. Percobaan pertama, yang menggunakan 3 konsentrasi diazinon 0. 2 dan 4 ppm dan 3 ulangan, mempelajari pertumbuhan rotifera, cladocera dan copepoda. Percobaan kedua mempunyai 2 perlakuan, yaitu diazinon 0 dan 4 ppm (yang terbaik dari percobaan pertama) serta 4 ulangan untuk mengevaluasi: 1) ketersediaan, pemanfaatan dan susunan jasad-jasad pakan, 2) pertumbuhan dan kelangsungan hidup larva, serta 3) perkembangan larva ikan. Larva yang berumur satu hari ditebar pada saat kelimpahan rotifera tertinggi di hapa dengan kepadatan 40 larva/1 atau 3.200 larva/hapa. Hapa (mesh 0,8 mm) yang berukuran 50x40x50 cm ditempatkan dalam kolam-kolam beton yang berukuran 4,25x2,00x 0,65 m. Kolam-kolam ini mula-mula dikeringkan selama 2 hari, dipupuk dengan kotoran ayam 1.000 g/m3 dan diisi air setinggi 50 cm. Keesokan harinya kolam dipupuk dengan urea dan tripel superfosfat masing-masing 20 dan 30 g/m3. Dua hari kemudian air diberi diazinon sesuai perlakuan. Hasil percobaan pertama menunjukkan bahwa diazinon meningkatkan ketersediaan rotifera. Populasi rotifera tertinggi dicapai di kolam yang mendapat diazinon 4 ppm. Percobaan kedua memberikan laju pertumbuhan harian dan kelangsungan hidup larva ikan serta ketersediaan dan pemanfaatan rotifer tertinggi pada pemberian diazinon 4 ppm. Kata kunci: Pakan alami, larva. Oxyeleotris marmorata, diazinon. kelangsungan hidup, pertumbuhan ABSTRACT Two experiments were conducted, without and with fish larvae. The first experiment, utilizing 3 concentrations of diazinon, i.e. 0, 2 and 4 ppm and 3 replications, evaluated the growth of rotifers, cladocerans and copepods. The second experiment had 2 treatments, i.e. 0 and 4 ppm diazinon and 4 replications evaluated: 1) the availability, utilization and composition of food organisms, 2) the growth and survival rates offish larvae, and 3) the development of larvae. One-day old larvae were stocked at times of highest rotifer concentrations in hapas at 40 larvae/1 or 3,200 larvae/hapa. Hapas (0,8 mm mesh) of 50x40x50 cm were placed in concrete ponds of 4.25x2.00x0,65 m. The ponds were dried for 2 days, fertilized with chicken manure 1.000 g/m3 and filled with water up to 50 cm deep. Next day, the ponds were fertilized with urea and triple superphosphate 20 and 30 g/m3 respectively. Two days later, the water was treated with diazinon according to treatments. The results of the first experiment showed that diazinon increased the availability of rotifers. The highest rotifer populations were obtained in ponds receiving 4 ppm diazinon. The second experiment gave highest daily growth and survival rates of fish larvae, te availability and utilization of rotifers at 4 ppm diazinon. Key words: Natural foods, larvae, Oxyeleotris marmorata, diazinon, survival, growth.

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37

Gravinese, Philip M., Ian C. Enochs, Derek P. Manzello e Robert van Woesik. "Ocean acidification changes the vertical movement of stone crab larvae". Biology Letters 15, n. 12 (dicembre 2019): 20190414. http://dx.doi.org/10.1098/rsbl.2019.0414.

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Anthropogenic activities are increasing ocean temperature and decreasing ocean pH. Some coastal habitats are experiencing increases in organic runoff, which when coupled with a loss of vegetated coastline can accelerate reductions in seawater pH. Marine larvae that hatch in coastal habitats may not have the ability to respond to elevated temperature and changes in seawater pH. This study examined the response of Florida stone crab ( Menippe mercenaria ) larvae to elevated temperature (30°C control and 32°C treatment) and CO 2 -induced reductions in pH (8.05 pH control and 7.80 pH treatment). We determined whether those singular and simultaneous stressors affect larval vertical movement at two developmental stages. Geotactic responses varied between larval stages. The direction and rate of the vertical displacement of larvae were dependent on pH rather than temperature. Stage III larvae swam upwards under ambient pH conditions, but swam downwards at a faster rate under reduced pH. There was no observable change in the directional movement of Stage V larvae. The reversal in orientation by Stage III larvae may limit larval transport in habitats that experience reduced pH and could pose challenges for the northward dispersal of stone crabs as coastal temperatures warm.

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38

Widiastuti, Zeny, Fahruddin Fahruddin e I. Gusti Ngurah Permana. "PENGARUH PENGAYAAN Artemia sp. DENGAN SUMBER DHA YANG BERBEDA TERHADAP SINTASAN LARVA LOBSTER PASIR (Panulirus homarus)". Media Akuakultur 16, n. 1 (3 luglio 2021): 21. http://dx.doi.org/10.15578/ma.16.1.2021.21-31.

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Abstract (sommario):

Kegiatan pembenihan lobster masih dikembangkan di Indonesia. Sintasan yang rendah dan pakan yang sesuai masih menjadi masalah utama dalam kegiatan pembenihan lobster. Artemia sebagai pakan utama diduga belum mencukupi kebutuhan nutrisi larva lobster. Upaya pemberian bahan pengaya sebagai alternatif untuk meningkatkan nutrisi diharapkan dapat meningkatkan sintasan larva lobster. Pemberian bahan pengaya yang mengandung asam lemak dokosa heksanoid acid (DHA) ke Artemia dianggap penting bagi pertumbuhan dan sintasan pada krustasea. Tujuan penelitian ini untuk mengetahui performa larva lobster berdasarkan tingkat sintasan maupun perkembangan larva dengan pemberian pakan artemia yang diperkaya dengan DHA. Perlakuan yang diberikan meliputi Artemia yang baru menetas (A), Artemia yang diperkaya dengan plankton Isochrysis galbana strain Tahiti konsentrasi (1-1,5 x 106 sel/mL) (B), DHA selco dosis 0,6 g/L (C), dan Artemia inkubasi 18 jam tanpa pengayaan (D). Pemeliharaan larva dilakukan pada bak 100 L dengan sistem air stagnan. Perkembangan larva yang mampu dicapai pada semua perlakuan adalah stadia-IIIa. Pemberian Artemia yang diperkaya dengan DHA selco menunjukkan hasil sintasan yang lebih baik pada pemeliharaan enam hari pertama namun tidak memberikan pengaruh yang signifikan. Pada masa pemeliharaan sampai 20 hari terjadi penurunan sintasan (SR) mencapai hanya 1%. Hal ini disebabkan adanya bakteri dan protozoa seperti jenis protozoa Zoothamnium sp. dan bakteri berfilamen teramati menempel pada tubuh larva sehingga mengganggu pergerakan dan kemampuan larva dalam menangkap mangsa. Berdasarkan penelitian ini maka penggunaan pakan Artemia yang diperkaya DHA Selco dapat menjadi alternatif pakan larva lobster namun tetap diperlukan kontrol kualitas air yang baik.Efforts to culture spiny lobster, Panulirus homarus larvae are still being developed in Indonesia. One of the main challenges in lobster hatcheries is to find an appropriate feed and improving larval survival. Artemia has been used as the main feed and considered to have insufficient nutritional ingredient for lobster larvae. Enrichment of feed to improve its nutrient contents is expected to increase the larval survival. DHA-enriched feed is considered essential for growth and survival of crustaceans. The aim of this study was to determine the survival and development of larvae fed with DHA-enriched Artemia. The treatments consisted of newly hatched Artemia (A), enriched Artemia with phytoplankton, Isochrysis galbana strain Tahiti at a density of 1-1.5 x 106 cells/mL (B), enriched Artemia with DHA selco at a dose of 0.6 g/L (C), and Artemia incubated for 18 hours without DHA enrichment (D). Each Artemia enrichment was performed for 18 hours. Larval rearing was carried out in a 00 L tank with static water system. The achieved larval developmental stage in all treatments was stage-IIIa. Administration of enriched Artemia with DHA selco showed a better larval survival during the first six days of larval rearing. But, it did not give any significant effect. The survival was then decreased to only 1% on day-20. This was due to the presence of bacteria and protozoa which decreased water quality. Protozoa Zoothamnium sp. and filamentous bacteria were observed attaching to the body of the larvae, disrupting the movement and ability of larvae in capturing prey. Based on this research, the use of Artemia enriched with DHA selco as an alternative for lobster larvae feed, but better water quality control is still needed.

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39

Edelson, J. V., M. Peters, J. Duthie e W. Roberts. "Control of Lepidopterous Larvae on Collard, 1997". Arthropod Management Tests 23, n. 1 (1 gennaio 1998): 91. http://dx.doi.org/10.1093/amt/23.1.91.

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Abstract Collard seed was planted in Mar at the AREC, Lane, OK. The experimental design was a RCB with 4 replicates and 9 treatments. Plots were 2 rows wide (72 inches) and 20 ft long with 20 ft alleys cut between plots. Plots were treated with insecticides using a CO2-powered backpack sprayer with a broadcast application of 72 inches from 4 hollow-cone nozzles applying 33 gal/A at 40 psi. Plots were treated on 4, 8, and 14 Jul. Plots were surveyed to determine larval abundance on 7, 11, and 17 Jul by examining 3 plants per plot and recording all larvae present.

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40

Klokočovnik, Vesna, Eva Veler e Dušan Devetak. "Antlions in interaction: confrontation of two competitors in limited space". Israel Journal of Ecology and Evolution 66, n. 1-2 (19 dicembre 2019): 73–81. http://dx.doi.org/10.1163/22244662-20191058.

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Abstract The study focused on the behaviour of sit-and-wait antlion larvae in interspecific interactions. Antlion larvae usually occur in clusters with a high density of individuals; therefore, competition can be intense. We observed two abundant antlion species, E. nostras and M. formicarius, which co-occur in some habitats. In a simple habitat choice experiment where substrates differed according to sand particle size, we found that E. nostras exhibited dominance over M. formicarius. Most E. nostras larvae remained in the more suitable substrate and constructed pits, while all the M. formicarius larvae moved out of the suitable area, and did not build pits. In the second experiment, we observed the characteristics of the pit-fall traps and scored the occurrence of larval relocation in relation to interactions and in the control group, where larvae were kept in containers separately. In interactions, the larvae of E. nostras constructed smaller pits, but pit enlargement was greater in comparison to the control group. M. formicarius larvae constructed similar sized pits in both groups; however, enlargement was greater in the control group. Relocation of larvae occurred only during interactions. In direct interactions, we found 15 behavioural patterns, which are described in detail for the first time. In the presence of a competitor, larvae showed intense territorial behaviour. We recorded several behavioural patterns during larval confrontation, and interestingly, intraguild predation rarely occurred. In most cases, E. nostras larvae outcompete M. formicarius, which was evident from the larger pits and the rate of pit-construction.

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41

Sharma, Sudhendu, Ravinder Singh e C. K. Gill. "Efficacy of anthranilic insecticide E2Y45 20 SC (Chlorantraniliprole) against Plutella xylostella L. in cabbage, Brassica oleracea var. capitata". Journal of Applied and Natural Science 8, n. 3 (1 settembre 2016): 1584–88. http://dx.doi.org/10.31018/jans.v8i3.1004.

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Abstract (sommario):

Experiments were conducted at farmerâ€™s cabbage fields to evaluate the bioefficacy of anthranilic insecticide i.e. E2Y45 20 SC (Chlorantraniliprole) having novel mode of action against the diamondback moth Plutella xylostella L. E2Y45 20 SC was applied @ 25.0, 37.5 and 50.0 ml/ha and was compared with Padan 50 SP (cartap hydrochloride) @ 500 g/ha and the untreated control. Lowest mean larval population after two sprays was recorded in higher dose of E2Y 45 20 SC i.e. @ 50.0 ml/ha (0.08 larvae/plant) at 7 days after treatment followed by medium and lower dose of E2Y 45 20 SC i.e. @ 37.5ml/ha (0.10 larvae/plant) and 25.0 ml/ha (0.33 larvae/plant). The larval population in these treatments was significantly lower than standard check, Padan 50 SP (2.56 larvae/plant), and untreated control (9.73 larvae/plant). The highest marketable yield (262.89 q/ha) was recorded in E2Y 45 20 SC @ 50.0 ml/ha which was significantly higher than Padan 50 SP (239.65 q/ha). Lowest yields were recorded in untreated control (106.00 q/ha). Conclusively, medium (37.5 ml/ha) and higher (50.0 ml/ha) dose of E2Y 45 20 SC (chlorantraniliprole) significantly reduced the larval population of P. xylostella and increased the cabbage yield.

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42

FERRAZ, ADRIANA C. P., DANIELE L. DALLAVECCHIA, DÉBORA C. SILVA, RENATO G. SILVA-FILHO e VALÉRIA M. AGUIAR. "Post-embriononic development of Chrysomya putoria(Diptera: Calliphoridae) on a diet containing ampicillin in different concentrations". Anais da Academia Brasileira de Ciências 88, n. 1 (4 marzo 2016): 105–16. http://dx.doi.org/10.1590/0001-3765201620140440.

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Here we evaluate the effects of different concentrations of the antibiotic ampicillin on the growth and development of Chrysomya putoria. Third-generation, first instar larvae (L1) reared on 60 grams of homogenate+agar 65% were treated with ampicillin sodium. The experiment consisted of four replicates (40 larvae/replicate) of each antibiotic concentration tested (T1: 466µg/mL ; T2: 81.33 mg/mL and T3: 166.66mg/mL) and a T4: control. The body mass of the mature larvae, after they abandoned the diet, were recorded in batches of five. The variation between the mean body mass of larvae and the duration of larval and pupal stages, and overall duration of the development, viability and normal rates were analyzed by ANOVA. There were no significant differences between the four treatments in the following parameters: body mass of larvae that discontinued the diet as well as the duration of larval, pupal, and total development. The sex ratios found in the four treatments did not differ from those expected. Normality rates were 100% for all treatments. There were no significant differences between treatments for larval and overall viability, but pupal viability differed significantly between T1 and the control, T1 and T2, and between the control and T3. The antibiotic did not appear to significantly alter the development of C. putoria.

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43

Cubillos, V. M., O. R. Chaparro, Y. A. Montiel e D. Véliz. "Unusual source of food: impact of dead siblings on encapsulated embryo development of Crepipatella fecunda (Gastropoda : Calyptraeidae)". Marine and Freshwater Research 58, n. 12 (2007): 1152. http://dx.doi.org/10.1071/mf07094.

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Embryonic cannibalism has been identified in directly developing calyptraeid species through observation of the ingestion of encapsulated sibling embryos. The object of the present study was to determine the effects of experimentally induced cannibalism on larval development in encapsulated larvae of Crepipatella fecunda (a species having mixed development). The effects studied included the time of intracapsular development, protoconch size and velar characteristics of the larvae. Mortality was induced during intracapsular development through mechanical disruption (‘treatment’) of embryos. A treatment and control group of embryos from the same female were compared. Encapsulated veligers actively fed on their sacrificed congeners. Larvae hatched in less than 10 days from treated capsules and had mean shell lengths and velum areas significantly lower than those from the control, but no significant differences in cilia length. In treated capsules where the embryos underwent a slow development (>20 days), the larvae produced shells, vela and cilia larger than those of the controls. In an intermediate period of intracapsular development, the differences recorded among larval characters were not statistically significant. The results showed that: (1) the encapsulated veligers were capable of feeding on exogenous food before hatching; (2) the consumption of non-living congeners decreased the time of intracapsular development; and (3) the morphometry of the larvae hatching from treated capsules varied depending on the period of intracapsular development and seems to be adaptively stabilised towards homogeneous larval morphometry.

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44

Wikeem, Brian M., George W. Powell e Allen Sturko. "BIOLOGY OF CYPHOCLEONVS ACHATES (COLEOPTERA: CURCULIONIDAE), PROPAGATED FOR THE BIOLOGICAL CONTROL OF KNAPWEEDS (ASTERACEAE)". Canadian Entomologist 131, n. 2 (aprile 1999): 243–50. http://dx.doi.org/10.4039/ent131243-2.

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AbstractCyphocleonus achates (Fahraeus) is a weevil used for the biological control of diffuse knapweed, Centaurea diffusa Monnet Del La Marck, and spotted knapweed, Centaurea maculosa Monnet Del La Marck, in North America. This research provided specific information on the biology of this insect in British Columbia. Adult weevils were released at six densities (1, 2, 4, 8, 16, and 32 male–female pairs) in each of 2 years into plots containing spotted knapweed. Larvae per plant, larval mass, larval survival, adult emergence, and air temperature were measured. Larval production increased with the release density of weevils in both the 1992 cohort and the 1993 cohort. Larval mass did not differ between years. Larval mass also did not vary with the release density of adults or the number of larvae per root. Larval survival of the 1993 cohort ranged from 17 to 48%, whereas that of the 1994 cohort ranged from 0 to 91%. Adult emergence began after the accumulation of 726–1144 degree-days. For both cohorts the date of first emergence occurred earlier, as the average number of larvae per plant increased for both cohorts. Increasing competition for food or space in the roots can induce early emergence. Sex ratios did not vary with date of emergence or release density of adult weevils. Adult emergence increased with the release density in the 1992 cohort, suggesting the average larval densities did not exceed the carrying capacity of the roots. The peak emergence rate increased with the release density in the 1992 cohort, but not in the 1993 cohort because of lower larval survival.

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45

Young, S. Y., e D. C. Steinkraus. "Control of Armyworm on Heading Wheat with Bacillus Thuringiensis Products and Baculoviruses, 1994". Arthropod Management Tests 21, n. 1 (1 gennaio 1996): 318–19. http://dx.doi.org/10.1093/amt/21.1.318a.

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Abstract All applications were made on 26 Apr to ‘Wakefield’ winter wheat drilled on 6 inch row spacings on heading wheat in Lonoke Co., AR. A bicycle-type CO2 sprayer with a 12 ft boom equipped with TX-4 hollowcone nozzles on a 20-inch spacing, calibrated to deliver 10.5 gal/acre at 40 psi, was used for all treatments. Plots were 12 X 50 ft separated by 6 ft borders, arranged in a RCB design with 4 replications. A spreader sticker (CS-7) was added at a concentration of 1 ml/gal. The application was made late in the afternoon in a moderate breeze. No rainfall occurred during the test. Six Bacillus thuringiensis products and 3 viruses [Anagrapha falcifera NPV (AfNPV), Pseudaletia unipuncta NPV (AWNPV) and P. unipuncta GV (AWGV) were tested. Larval precounts made from the perimeter of the plots prior to the application showed a mean of 14.9 larvae per ft2. Post application larval counts were made at 4 and 7 DAT. Two samples per plot, each 3 ft in length and 12 inches in width, were taken by searching the soil surface, debris, and base of plants for larvae. Just prior to the search, the plants were jostled so that larvae on plants would fall to the ground. Yields were not taken. Larvae were collected from control and virus plots at 4 and 7 DAT. Larvae (25 per replicate) were individually placed in 1 oz plastic cups half-filled with pinto bean diet and held until death or adult emergence. Data from counts and collections were analyzed by ANOVA.

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46

Wilson, J. R. U., M. Rees e O. Ajuonu. "Population regulation of a classical biological control agent larval density dependence inNeochetina eichhorniaeColeoptera Curculionidae, a biological control agent of water hyacinthEichhornia crassipes". Bulletin of Entomological Research 96, n. 2 (aprile 2006): 145–52. http://dx.doi.org/10.1079/ber2005408.

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AbstractThe release of classical biological control agents has reduced the economic, environmental and social problems caused by water hyacinth,Eichhornia crassipes; however, additional control measures are needed in some locations. Water hyacinth plants were treated with different densities of eggs of the weevilNeochetina eichhorniaeWarner, one of the main control agents, under different nutrient regimes in a controlled experiment. Plants were destructively sampled and the development ofN. eichhorniaewas assessed. The survival of first and second instars declined as larval density increased. Plant nutrient status did not directly affect the mortality rate of larvae, but at higher nutrient concentrations larvae developed faster and were larger at a given developmental stage. It is argued that the density dependence operating inN. eichhorniaeoccurs through an interaction between young larvae and leaf longevity. Consequently, events which disrupt water hyacinth leaf dynamics, e.g. frost or foliar herbicides, will have a disproportionately large effect on the control agents and may reduce the level of control of the host.

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47

Saepudin, Malik, Soeharyo Hadisaputro, Ari Suwondo e Suhartono Suhartono. "The Effect of Rekattidiri Ovitrap towards Aedes aegypti Larval Density". International Journal of Public Health Science (IJPHS) 6, n. 1 (1 marzo 2017): 78. http://dx.doi.org/10.11591/ijphs.v6i1.6536.

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Abstract (sommario):

Dengue Hemorrhagic Fever (DHF) is a health problem in Indonesia. The entire region of Indonesia at risk of contracting dengue disease. The study aims to prove the effect of modifications ovitrap rekattidiri on the density of larvae (HI: House Index, CI: Container Index and BI: Breteu Index) as well as comparing the differences between the mean larvae trapped between ovitrap Rekattidiri with standard ovitrap. Using a quasi experimental design, time series experimental design with Control group. Population subjects were Aedes aegypti at the endemic sites in Pontianak, West Borneo. The results showed larval density index in the intervention area decreased each ie HI from 26% to 3%, CI of 6.95% to 2.19 %, and BI from 29% to 13%. The number of larvae trapped in ovitrap rekattidiri ie 70% (12,770 larvae) more than the standard ovitrap in the control and intervention, namely: 17% (3,057 larvae) and 13% (2,334 larvae). It is concluded that there are significant modifications Rekattidiri ovitrap against larval density index (HI p-value: 0.025, CI p-value: 0.052, BI value of p: 0.04) and there are differences between the mean larvae trapped in ovitrap Rekattidiri and standard ovitrap with p value: 0.001.

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48

Saepudin, Malik, Soeharyo Hadisaputro, Ari Suwondo e Suhartono Suhartono. "The Effect of Rekattidiri Ovitrap towards Aedes aegypti Larval Density". International Journal of Public Health Science (IJPHS) 6, n. 1 (1 marzo 2017): 80. http://dx.doi.org/10.11591/.v6i1.6536.

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Abstract (sommario):

Dengue Hemorrhagic Fever (DHF) is a health problem in Indonesia. The entire region of Indonesia at risk of contracting dengue disease. The study aims to prove the effect of modifications ovitrap rekattidiri on the density of larvae (HI: House Index, CI: Container Index and BI: Breteu Index) as well as comparing the differences between the mean larvae trapped between ovitrap Rekattidiri with standard ovitrap. Using a quasi experimental design, time series experimental design with Control group. Population subjects were Aedes aegypti at the endemic sites in Pontianak, West Borneo. The results showed larval density index in the intervention area decreased each ie HI from 26% to 3%, CI of 6.95% to 2.19 %, and BI from 29% to 13%. The number of larvae trapped in ovitrap rekattidiri ie 70% (12,770 larvae) more than the standard ovitrap in the control and intervention, namely: 17% (3,057 larvae) and 13% (2,334 larvae). It is concluded that there are significant modifications Rekattidiri ovitrap against larval density index (HI p-value: 0.025, CI p-value: 0.052, BI value of p: 0.04) and there are differences between the mean larvae trapped in ovitrap Rekattidiri and standard ovitrap with p value: 0.001.

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49

Sugauara, Elisangela Yumi, Isabelle Luiz Rahal, Herika Line Marko de Oliveira, Wanessa de Campos Bortolucci, Carla Maria Mariano Fernandez, Maria Graciela Iecher Faria, Suelen Pereira Ruiz et al. "Inga laurina crude extract to control Aedes aegypti". Research, Society and Development 9, n. 11 (11 novembre 2020): e1819119683. http://dx.doi.org/10.33448/rsd-v9i11.9683.

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Abstract (sommario):

Aedes aegypti is the um mosquito responsible for the transmission of several diseases to humans such as dengue, chikungunya, Zika virus and urban yellow fever. The control of this culicid is done by utilizing insecticides that cause insect resistance. Therefore, natural alternatives to control A. aegypti have been sought. Thus, the objective of our work was to characterize the chemical composition of the crude extract of the leaves of Inga laurina and to evaluate the insecticidal activity of the extract on the larvae of A. aegypti. The crude extract was prepared form dry leaves by dynamic maceration using alcohol 96º GL as extracting solvent. The chemical identification of the compounds found in the crude extract was done by a gas chromatography coupled to mass spectrometry. The larvicidal activity was determined by larval packet test in third-stage development larvae A. aegypti. Fifteen compounds were identified in the leaves and the major ones were γ- sitosterol (34.39%), phytol (14.51%), squalene (8.57%) and stigmasterol (7.38%). I. laurina leaf crude extract presented larvicidal activity potential against A. aegypti larvae presenting lethal concentration of 50% (CL50) of 0.98 mg/mL and 99% (CL99) of 2.69 mg/mL. Thus, I. laurina leaf crude extract presented rich composition of phytosterols and promising insecticide activity against A. aegypti larvae, offering new possibilities for the application and development of products.

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50

Li, Zhiguo, Mengshang Hou, Yuanmei Qiu, Bian Zhao, Hongyi Nie e Songkun Su. "Changes in Antioxidant Enzymes Activity and Metabolomic Profiles in the Guts of Honey Bee (Apis mellifera) Larvae Infected with Ascosphaera apis". Insects 11, n. 7 (6 luglio 2020): 419. http://dx.doi.org/10.3390/insects11070419.

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The fungus Ascosphaera apis, an obligate fungal pathogen of honey bee brood, causes chalkbrood disease in honey bee larvae worldwide. Biological characteristics of the fungal pathogen and the molecular interactions between A. apis and honey bees have been studied extensively. However, little is known about the effects of A. apis infection on antioxidant enzyme activities and metabolic profiles of the gut of honey bee larvae. In this study, sandwich enzyme-linked immunosorbent assay and LC-MS based untargeted metabolomic analysis were employed to determine the changes in the specific activities of antioxidant enzymes and the metabolomic profiles in gut tissues of A. apis-infected larvae (105 A. apis spores per larva) and controls. Results showed that specific activities of superoxide dismutase, catalase and glutathione S-transferase were significantly higher in the guts of the control larvae than in the guts of the A. apis-infected larvae. The metabolomic data revealed that levels of 28 and 52 metabolites were significantly higher and lower, respectively, in the guts of A. apis-infected larvae than in the guts of control larvae. The 5-oxo-ETE level in the infected larvae was two times higher than that in the control larvae. Elevated 5-oxo-ETE levels may act as a potential metabolic biomarker for chalkbrood disease diagnosis, suggesting that A. apis infection induced obvious oxidative stress in the honey bee larvae. The levels of metabolites such as taurine, docosahexaenoic acid, and L-carnitine involved in combating oxidative stress were significantly decreased in the gut of A. apis-infected larvae. Overall, our results suggest that A. apis infection may compromise the ability of infected larvae to cope with oxidative stress, providing new insight into changing patterns of physiological responses to A. apis infection in honey bee larvae by concurrent use of conventional biochemical assays and untargeted metabolomics.

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