Studies On The Oviposition Pepellent Effect And Appliction Technology Of Pyrethroid Insecticides Against Bactrocera Cucurbitae On Mamordica Charantia

The melon fly is a pest that causes some of the most severe loss to the gourd vegetable in China, and it’s also the most difficult pest to take any precaution of. This essay mainly studies the melon fly’s oviposition repellent’s bioassay method, screening out pyrethroids that has effective repelling effects to the melon fly’s oviposition, observing the effects of the oviposition repellent on the female melon fly’s egg laying behaviour, examining the electroantnnography and the olfactory reaction it had to the repellent, and opens up oviposition repellent’s agricultural application research. The result of the research will further enrich the studies of the melon fly’s egg laying repelling effect, provide the oviposition repelling application with scientific proof and this will bring great significance to our nation’s precautionary measure against the melon fly.1. Deltamethrin and cypermethrin have strong oviposition repellent effect on the melon fly. In this study, nine pyrethroids were selected to test the oviposition repellent effect on the melon fly. The results showed that 25mg/L pyrethroids treatment against the melon fly, the fecundity was significantly less than the control group, the oviposition repellent rate about deltamethrin and cypermethrin was higher, which were respectively 92.72% and 89.11%, the interference index of population control were 0.07 and 0.11.2. There was a significant difference in the response of the different pyrethroids against the melon fly. Use electroantennography to test the EAG response of the melon fly. The results show that the EAG response of deltamethrin against the melon fly female was the highest, reached 2.225, the EAG response of cypermethrin against the melon fly female was 1.962 and the EAG response of cyfluthrin against the melon fly female was the lowest, which was only 0.972. For the same kind of pyrethroids, the melon fly male’ and female’ EAG responses were significantly different. The female’ EAG responses were higher than the male’ EAG responses, such as the EAG response of deltamethrin against the melon fly female was 2.225 and the EAG response of deltamethrin against the melon fly male was 0.752, which was 2.96 times more than the male’ EAG response.3. Use Y type olfactory to test the response of pyrethroids against the melon fly. The results showed that the repellent rate of deltamethrin against the melon fly males was 55.56%, but for the melon fly females, the repellent rate was up to 82.67%.The repellent rate of cyfluthrin against the melon fly males was low, the repellent rate was 17.95% for the males and the repellent rate was 21.55% for the females. The higher the melon fly female’EAG response was, the higher the repellent rate of the female’olfactory response was, meaning the repellent effect was better. The EAG response of deltamethrin against the melon fly females was the highest, which reached 2.225 and the repellent effect was strongest, which was 82.67%. The lowest EAG response was cyfluthrin against the melon fly females, which was 0.972 and the repellent rate was only 21.55%.4. Pyrethroids had obvious influence on the melon fly oviposition behavior. Observe the melon fly females’fruit visiting times, trial spawning time, spawning time and fecundity. Test results found that females’ fruit visiting times, trial spawning times, spawning time and fecundity were significantly reduced.5. Sprayed pyrethroids to control the melon fly. The test results showed that the control effects about deltamethrin or cypermethrin against the melon fly was best. In 25 mg/L concentration conditions, the control effect of deltamethrin and cypermethrin against the melon fly were 83.33% and 77.78%,70.21% and 64.84%,26.47%and 23.65%,3 days 5 days and 7 days after the treament.6. Sprayed the plant surface agent 400 times diluted and the pyrethroids in the whole field, the control effect on the melon fly was better. Mixed the plant surface agent 400 times diluted with 2.5% deltamethrin 1000 times, the control effect were respectively 94.44%,93.98% and 69.56% 3 days,5 days and 7 days after the treament. Compared with the effect of single plant surface agent or the effect of single deltamethrin, the control effect of the melon fly was better. Mixed the plant surface agent 400 times diluted with 50 g/L cypermethrin 2000 times, the control effect were respectively 88.89%,93.98% and 63.77% 3 days,5 days and 7 days after the treament. Compared with the single plant surface agent or single cypermethrin, the control effect of the melon fly was significant.7. Sprayed deltamethrin or cypermethrin combining with plant surface agent and bagging technology, the control effect against the melon fly improved.2.5% deltamethrin 1000 times with plant surface agent 400 times diluted and bagging, the control effect was best, which reached 95.83% 3 days,7 days and 14 days after the treament.50 g/L cypermethrin 2000 times with plant surface film agent 400 times diluted and bagging, the control effect was best, which was 91.07% 3 days,7 days and 14 days after the treament. Others control effects decreased significantly.8. In the fruits flowering period, spray 2.5% deltamethrin EC 1000 times and plant surface agent 400 times diluted or 50 g/L cypermethrin 2000 times with plant surface agent 400 times diluted, combined with bagging technology, bagging while 3 days after flowering, which can control the melon fly effectively.