Dissertation > Agricultural Sciences > Plant Protection > Pesticide ( chemical control ) > Plant chemical protection theory

Studies on Mechanism for Tebufenozide Resistance of Diamondback Moth Plutella Xylostella (L.)

Author CaoGuangChun
Tutor HanZhaoJun
School Nanjing Agricultural College
Course Agricultural Entomology and Pest Control
Keywords Diamondback moth, Plutella xylostella Resistance Mechanism Tebufenozide Resistant strains Susceptible strain Detoxification Resistance management Insect growth regulator Avermectin
CLC S481
Type Master's thesis
Year 2003
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Plutella xylostella Plutella xylostella (L.) is an important pest of cruciferous vegetables, is resistant to one of the most serious pest of pesticides. Their reproductive ability, short generation time, irregular development, generations overlap serious, and can be transported long distances. These characteristics are conducive to the development of diamondback moth resistant. Produce different levels of DDT and other pesticides in different regions of pyrethroids, carbamates, organophosphorus acylurea insect growth regulators kill silkworm toxins, microbial insecticides has been disabled in the Resistance reported. Tebufenozide (tebufenozide) Rohm and Haas Company, USA to develop a new class of pesticides, only Lepidoptera active, its mode of action and the steroidal ketones peeling hormone and the peeling hormone receptor (ECR ) combined at the molecular level by gene regulation to stimulate the peeling process, it is the same steroid ketones peeling hormone different places in that in insects, it can not be quickly degraded resulting in the presence of the of steroidal ketones peeling hormone can can not express the downstream gene expression, which led to the peeling process can not be successfully completed, so that the insects can not complete peeling death. The diamondback moth susceptible strain for the materials of tebufenozide resistant strains Breeding, found 15.7-fold resistance to diamondback moth tebufenozide 7th generation screening, and presents the characteristics of rapidly rising slowly at first. A significant increase of the resistance force phoxim, acephate, hexaflumuron card dead grams by 10.113-fold resistance to tebufenozide found bioassay of sensitive and resistant strains of diamondback moth strains, its LD 50 increased produce 2.051,2.302,1.765 and 2.963 times more to produce a 13-fold cross-resistance to abamectin. Deltamethrin, cypermethrin and trichlorfon tolerated and did not produce significant changes. Tebufenozide sensitive and resistant Plutella object of study, the determination of the difference between the sensitive and resistant strain male and female larvae metabolic enzymes found resistant Plutella esterase metabolic rate enhancement and reduced affinity, wherein the estrogen The most obvious impact of insects, Vm values ??increase 1.69 times and 43.55 times lower Km values. Glutathione transferase vitality also significantly enhanced, increased vitality most obvious DCNB as substrate. Female vitality enhancement of 1.25 times, while the male enhancement of 1.57 times. Microsomal mixed function oxidase enzyme O-demethylase activity has increased significantly, both male and female are 1.3 times more the synergist PBO synergistic experiment also proved this point. This shows that the diamondback moth resistance early stage, the meter is full detoxification enzyme raise important mechanism. Diamondback moth by constructing meters the full resistant strains (RT) and susceptible strain (S 0 ) experimental population life table, compare a series of growth and reproduction characteristics, and net reproductive rate (R 0 ) to determine the relative fitness of the two strains. The results show that, compared to RT strains with sensitive strain having a certain degree of breeding adverse, including the fecundity decreased hatchability of reduction, as well as the sex ratio changes. No observed adverse larval developmental. RT strain relative to the susceptible strain of 0.61 relative fitness. This shows Plutella resistance make biological suitable decreased markedly. The study suggests that tebufenozide is a mechanism of special new insecticides, Daejeon promotion Chinese Abstract, diamondback moth still have the risk of resistance. Should therefore pay attention to the rational use of drugs and resistance management. The Resistance Mechanism find, diamondback moth meters full early resistance mainly through detoxification capacity enhancements. It can be considered that the synergist was added in the formulation to enhance the cytotoxic effects of the antagonistic individual. In addition, the study found resistant Plutella fitness decreased, therefore, can take advantage of Pharmacy rotation for resistance management, but should avoid the use of cross-resistance to abamectin Pharmacy.

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