Littérature scientifique sur le sujet « Nucleopolyhedro virus »

ABSTRACT Helicoverpa armigera (Hubner) is an important pest of corn crops. Lecanicillium sp. and Helicoverpa armigera Nucleopolyhedro virus (HearNPV) are biological control agents that are safe for the environment. This study observed pathogenicity of HearNPV and Lecanicillium sp. against eggs and larvae H. armigera. The results showed that HearNPV application was not able to infect eggs, but the mortality effects of newly hatched larvae and second instars larvae at density of 107 was 100% and 90% respectively, while in mixed applications Lecanicillium sp. and HearNPV on eggs at 107 caused 17.5%, and eventually died were 100%. At 107 concentration with mixure of application (Lecanicillium sp. and HearNPV) mortality was only 26.25%. The value of LT50 in HearNPV application against H. armigera larvae was 2.03 days faster than that of mixed applications on 3.23 days. A conclusion statement HearNPV was more effective against H. armigera than mixed application (HearNPV and Lecanicillium sp.)

Field efficacy of seven geographical isolates of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) along with an insecticide control was evaluated against H. armigera on cotton and chickpea in the Coimbatore district of Tamil Nadu, India. Among the HaNPV isolates, CBE I (Coimbatore) and NEG (Negamum) applied at 3.0 × 10¹² POB/ha to cotton and 1.5 × 10¹² POB/ha to chickpea with an adjuvant, crude sugar, significantly reduced the H. armigera larval population and increased the yield. CBE I and NEG recorded the highest yield of 2038 kg/ha and 2033 kg/ha, which was on a par with endosulfan (2026.7 kg/ha) with cost/benefit ratios of 1:2.32, 1:2.48, and 1:1.12, respectively, on cotton. In chickpea grain yields of 980, 983, and 973.3 kg/ha and cost/benefit ratios of 1:1.36, 1:1.48 and 1:0.87, respectively, in CBE I, NEG and endosulfan treated plots were obtained. The isolate RAJ (Rajasthan) recorded the lowest yield comparable to that of the untreated control in both crops.

The silkworm Bombyx mori.L. is infected by various diseases viz; grasserie, flacherie, muscardine, and pebrine. Among all these diseases the grasserie causes major economic loss to the industry and is one of the main reasons for low silk productivity. It is caused by a virus known as Bombyx mori nucleopolyhedro virus (BmNPV). The impact of grasserie disease on silkworms is significant as it leads to reduced silk production and can result in economic losses for sericulture farmers. In India greater than 50% of silk cocoon crop loss is due to BmNPV [1] and in Kashmir valley, the loss is about 28-32% [2]. Silk obtained from the cocoons of silkworm Bombyx mori L. is a natural fibrous protein well known for being lightweight, having high mechanical strength, good flexibility, and luster making it ideal for the textile industry. In addition, fibroin extracted from the cocoons of domesticated silkworm Bombyx mori L. has gained growingly interest due to its excellent mechanical properties and high biocompatibility, biodegradability, inexpensiveness, and preparation flexibility [3]. These properties of silk fibroin lead to the formulation of fibroin nanoparticles (FNP’-s) which can be used to encapsulate different types of therapeutic compounds like proteins, vaccines, enzymes, etc. Fibroin has been approved as a biomaterial by the Food and Drug Administration (FDA) and has been popularly used in numerous medical applications such as sutures, tissue regeneration, coating devices, and drug delivery systems [4]. It has been studied that SF-derived curcumin nanoparticles show higher efficacy against breast cancer cells and have the potential to treat in vivo breast tumors by local, sustained, and long-term therapeutic delivery as a biodegradable system [5]. Therefore, fibroin-coated nanoparticles can be used effectively for disease management.

碩士
國立臺灣大學
昆蟲學研究所
101
Baculovirus have long been recognized as an environmental friendly bio-insecticide, because they infect invertebrate only. The pathogenicity and specificity of baculoviruses have led to them being the alternative to chemical synthetic insecticides which always develop widespread resistance quickly. However, the practical use of baculovirus in pest control has been rather limited due to the difficulty of mass production and sensitive to ultraviolet (UV) radiation of virus. In vivo propagation in living insect is still the most reliable and economic strategy for mass production of baculovirus. Using living insects as a bioreactor for baculovirus production requires a large insect colony as a source of healthy larvae for virus occlusion bodies (OBs) inoculation. Afterward, the infected organisms are harvested as moribund or dead infected insects for virus extraction. The Spodoptera litura (F.) is a polyphagous, multivoltine and worldwide agricultural pest. Therefore, my studies focus on increasing the production of S. litura nucleopolyhedro virus (SpltNPV) by using Juvenile hormone (JH) and its analogs (JHA)-pyriproxyfen. In addition, my thesis also aims to explore silicon dioxide (SiO2) as a UV-protectant for SpltNPV. The preliminary results showed that JH- and pyriproxyfen-treatment can increase the virus production 2.26-folds and 1.95-folds (by weight), and 2.23-folds and 1.97-folds (OBs/larva) respectively. Moreover, the original activity remaining (%OAR) after 90 and 180 min UV radiation can be 40 and 32% respectively when the SpltNPV were encapulated with SiO2. The original activity remaining (%OAR) can be further enhanced to 72 and 60% respectively when the SpltNPV were further treated with green tea (1%) for 30 min. Instead of green tea, titanium dioxide and lignin treatment can only increase the %OAR to 54 and 55%, and 40 and 36% after radiation with UV for 90 and 180 minutes respectively.