Letteratura scientifica selezionata sul tema "Balaustium spp"

AbstractLeaves were collected between 28 July and 10 September from 36 (1986) and 85 (1987) apple orchards, and examined for mites. Twelve species of Phytoseiidae were found: Amblyseius fallacis (Garman), Typhlodromus longipilus Nesbitt, A. andersoni (Chant), T. caudiglans Schuster, T. pyri Scheuten, T. pomi (Parrott), Phytoseius macropilis (Banks), T. herbertae Chant, A. driggeri Specht, A. finlandicus (Oudemans), T. conspicuus (Garman), and A. pusillus (Kennett), in order of frequency. The stigmaeid mites Zetzellia mali (Ewing) and Agistemus fleschneri Summers, a complex of erythraeid mites of Balaustium spp. and Hauptmannia spp., and tydeid mites, primarily Tydeus spp., were other common predatory species. Species of Tetranychidae, Bdellidae, Eriophyidae, Winterschmidtiidae, and Tarsonemidae, also were collected.Predatory mites were present each season in all abandoned orchards and in 43–74% of the commercial orchards. Their abundance in commercial orchards was compared with the use of insecticides applied only for control of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.). Fewer (P < 0.05) phytoseiids occurred where pyrethroids were employed than in sites without pyrethroids, but differences were not found for similar use of the carbamoyl oxime, methomyl. Fewer (P < 0.05) stigmaeids occurred in sites treated with methomyl than in sites without methomyl, whereas such differences were not found for pyrethroid use.

This study investigated commensal feeding interactions between the European harvestman (P. opilio L.) and the predatory mites Balaustium spp. and Anystis baccarum L. It also investigated the feeding behaviour of P. opilio. Experiments were conducted in the laboratory using standardised temperature, humidity, photoperiod and experimental arenas, with eggs of the brown blowfly (Calliphora stygia F.) as prey facsimiles. Due to initial difficulties in obtaining enough predatory mites, mite feeding was manually simulated piercing blowfly eggs with a minuten pin. P. opilio consumed significantly more freeze-killed than live blowfly eggs, indicating that freezing induced chemical and/or physical changes to blowfly eggs that are detected by P. opilio. Significantly more manually pierced eggs were consumed by P. opilio compared with unpierced ones, demonstrating that piercing caused a chemical and/or physical to the egg and increased the feeding rates of P. opilio. Different densities of eggs had no effect on the numbers eaten by P. opilio and placing single pierced eggs next to groups of unpierced eggs also had no effect on the numbers of unpierced eggs eaten. These results suggest that P. opilio does not exhibit klinokinesis or orthokinesis to intensify its search for prey around the area where previous prey were located. P. opilio ate significantly more brown blowfly eggs that had previously been fed on by mites, demonstrating that a short term commensal interaction existed. However, further work is required to demonstrate if the relationship is commensal in the longer term. A comparison between hand-pierced and mite-pierced eggs showed that P. opilio ate significantly more of the former indicating that mite and hand piercing were quantitatively different. The potential for, and importance of, other commensal or mutual relationships between predators in agroecosystems is discussed. The lack of klinokinesis and orthokinesis in P. opilio is compared with other predators and parasitoids that do exhibit these behaviours. The means by which prey are detected by P. opilio are discussed in relation to interpreting behaviours such as prey inspection. Concerns about the effect of pre-treatment and handling of sentinel prey and the problems of using prey facsimiles are raised.

This study investigated commensal feeding interactions between the European harvestman (P. opilio L.) and the predatory mites Balaustium spp. and Anystis baccarum L. It also investigated the feeding behaviour of P. opilio. Experiments were conducted in the laboratory using standardised temperature, humidity, photoperiod and experimental arenas, with eggs of the brown blowfly (Calliphora stygia F.) as prey facsimiles. Due to initial difficulties in obtaining enough predatory mites, mite feeding was manually simulated piercing blowfly eggs with a minuten pin. P. opilio consumed significantly more freeze-killed than live blowfly eggs, indicating that freezing induced chemical and/or physical changes to blowfly eggs that are detected by P. opilio. Significantly more manually pierced eggs were consumed by P. opilio compared with unpierced ones, demonstrating that piercing caused a chemical and/or physical to the egg and increased the feeding rates of P. opilio. Different densities of eggs had no effect on the numbers eaten by P. opilio and placing single pierced eggs next to groups of unpierced eggs also had no effect on the numbers of unpierced eggs eaten. These results suggest that P. opilio does not exhibit klinokinesis or orthokinesis to intensify its search for prey around the area where previous prey were located. P. opilio ate significantly more brown blowfly eggs that had previously been fed on by mites, demonstrating that a short term commensal interaction existed. However, further work is required to demonstrate if the relationship is commensal in the longer term. A comparison between hand-pierced and mite-pierced eggs showed that P. opilio ate significantly more of the former indicating that mite and hand piercing were quantitatively different. The potential for, and importance of, other commensal or mutual relationships between predators in agroecosystems is discussed. The lack of klinokinesis and orthokinesis in P. opilio is compared with other predators and parasitoids that do exhibit these behaviours. The means by which prey are detected by P. opilio are discussed in relation to interpreting behaviours such as prey inspection. Concerns about the effect of pre-treatment and handling of sentinel prey and the problems of using prey facsimiles are raised.

Balaustium medicagoense (Acari: Erythraeidae) and Bryobia spp. (Acari: Tetranychidae) have recently been identified as emerging pests of winter crops and pastures by the Australian grains industry. The relative importance of these mites and damage caused by them in Australia has markedly increased in the last decade, and pest reports indicate extensive damage to a variety of winter grain crops and pastures. Furthermore, pest reports suggest that these mites have been difficult to control in the field, with some pesticides described as being ineffective. Despite this, there is very little information about the biology and control of these species, making it difficult to devise effective and sustainable management strategies. This thesis addresses some of these concerns by investigating various aspects of the biology, ecology and genetics of these mites in broad acre agriculture in southern Australia.
Laboratory bioassays were undertaken to examine the response of Ba. medicagoense and B. sp. I (along with the redlegged earth mite (Halotydeus destructor) as a point of reference) to several currently registered pesticides against earth mites. Balaustium medicagoense and B. sp. I generally had a much greater level of tolerance to the pesticides tested than H. destructor. These mites therefore have a high natural tolerance to currently registered pesticides and may prove difficult to control in the field. These findings suggest other strategies that are not reliant on chemicals should be considered for control of Ba. medicagoense and B. sp. I.
The effects of different crop plants on the survival and reproduction of Ba. medicagoense and Bryobia spp. (B. sp. VIII and B. sp. IX) and the plant damage caused by these mites were investigated under shade-house conditions. In addition information from field surveys and pest report bulletins was collated to test for outbreak patterns. The findings showed that these mites were polyphagous, attacking a variety of agriculturally important plants as well as numerous weeds within southern Australia. Therefore, these mites have the potential to be important pests on several winter grain crops and pasture, but there are important differences in host responses that might assist in management strategies such as targeted crop rotations and weed management.
The distribution, life cycle, seasonal abundance patterns and the pest status of Ba. medicagoense and Bryobia spp. were examined in southern Australia. Both mites are widely distributed throughout Mediterranean-type climate areas within southern Australia. Balaustium medicagoense has two generations per year and was active from March until December, with a likely diapause period in summer. There were differences in the seasonal abundance and life cycle of two species of Bryobia (B. sp. IX and B. sp. I). Bryobia sp. IX had two generations per year, was active from March until December, and was likely to be in diapause over the summer months. Bryobia sp. I did not have a diapause stage, was active year round and had approximately four generations per year. Seasonal abundance patterns of Ba. medicagoense and B. sp. IX overlapped with those of the major pest mite species H. destructor and Penthaleus major. A survey of pest outbreaks and chemical control failures showed that while H. destructor and the Penthaleus species remained important pests, outbreaks and control failures involving Ba. medicagoense and Bryobia spp. had increased over the last decade.
The species/strain status of Balaustium and Bryobia mites from broad acre environments was examined in southern Australia using a combination of mitochondrial and nuclear DNA sequence data. In addition, the reproductive mode and genetic diversity of Ba. medicagoense was examined using the amplified fragment length polymorphism (AFLP) method. Findings showed that Ba. medicagoense is the only species present in grain crops, pastures and roadsides within southern Australia, and at least seven species of Bryobia mites are present. The AFLP data revealed that Ba. medicagoense reproduces asexually and that genetic diversity was low with only 10 genotypes found from 16 populations.
Overall, the data presented in this thesis helps to explain why Ba. medicagoense and Bryobia spp. are emerging pests and points to ways in which these mites may be controlled in the future. The results show that these mites are difficult to control with currently registered pesticides, have a widespread distribution, can potentially increase in abundance rapidly under favourable conditions and persist across a wider range of seasonal conditions than other major pest earth mites. However, there are differences in pesticide susceptibilities and plant host responses that have the potential to be exploited when developing targeted control options for these pest mites.