Influence Of Planting Pattern And Varieties Of Peanut On The Frankliniella Intonsa(Trybom) Occurring And Its Control Technique Research

Peanut(Arachis hypogaea Linn.)is one of the important oil crops in China.Shandong province is main production areas of peanut in China.In recent years,with the changing of agricultural tillage system and climate factors affecting,thrips have become a main pest in peanut seedling stage.Thrips have small body and often hidden in the flowers and leaves.Their fertility is strong and could have many generations in same time leading to the high frequency outbreak.The diversification of peanut sowing date is suitable for the happening of the thrips,especially in dry weather.Up till now,there is less study on thrips and the changing of peanut planting cultivation way will affect its occurrence.Therefore,this study was to clear the thrips occurrence characteristics and the environmental effecting,evaluate the resistant peanut varieties to Frankliniella intonsa,screen efficient reagent and provide the basis for scientific prevention and control of thrips on peanut.The main results were as follows:1.Through the field survey of peanut in Taian,we found that Frankliniella intonsa occurred on spring peanut in early June and the infection peak appears at the end of June to early July peak.Rain period could reduce the number of Frankliniella intonsa by mechanical erosion of rain,and then it would have an obvious increase.In middle July,the insect number gradually declined.Late July was the end of harmful time.Frankliniella intonsa occurred on summer peanut in early July and the peak was late July,then the insect number gradually declined.Early August was the end of harmful time.2.By the field investigation,there were differences among spring peanut,summer peanut and intercropped peanuts.The spring peanut had the most serious harm with an average infected leaf rate of 12.48%.The intercropped peanut had a second serious harm with an average infected leaf rate of 9.48%.The summer peanut had a slight harm with an average infected leaf rate of 4.92%.3.The peanut had the more serious harm when it interplanted with corn.Under same cropping pattern,peanut with film-mulching cultivation had slighter harm than it with culturing in the open.4.There were significant differences in the harm degree among peanut varieties.Intwenty peanut varieties from Taian,606,Hua17 and Huayu24 had the resistance to thrips with lower insect number and infected leaf rate and Shanhua13,Shanhua 18 and Fenghua6 were sensitive to thrips.The others were middle.By investigating eleven peanut varieties planted in Qingdao,Xuzhouzhili and Huayu 36 had the resistance to thrips with lower insect number and infected leaf rate and Liaojin1,Huayu33 and Zhonghua12 were sensitive to thrips.In the laboratory test,we tested the selectivity of Frankliniella intonsa on different peanut varieties by leaf dish method.The results showed that the pest tend to be stable after 2hours.In the ten peanut varieties,Frankliniella intonsa had the strongest selectivity to Huayu33,Shanhua18 and Fenghua 6 with an average pest number of 13.25,14.50 and 11.75.The Hua17 had the weakest selectivity with an average pest number of 1.25.5.We compared the toxicity of nine insecticides on Frankliniella intonsa and Frankliniella occidentalis by TIBS.The results showed that spinetoram had the highest toxicity to both with LC50 of 0.049 mg/L and 0.044 mg/L.Secondly,emamectin benzoate,deltamethrin and abamectin also had high toxicity.Spirotetramat,clothianidin and tolfenpyrad had low toxicity.In the nine insecticides,spinetoram,emamectin benzoate,abamectin,cyantraniliprole and clothianidin had more toxicity on Frankliniella occidentalis with virulence ratio of 1.11,1.34,1.36,1.10,1.50 and 1.40 respectively.Deltamethrin,spirotetramat and tolfenpyrad had more toxicity on Frankliniella intonsa with virulence ratio of 0.56,0.66 and 0.85 respectively.6.The results of pot experiment showed that spinetoram had the best control effect on Frankliniella intonsa.3 days after treatment,2000 and 4000 diluent had 93.46% and 87.63%control effect respectively.It also had the long lasting period.14 days after treatment,the control effects were 89.80% and 83.28% respectively.Damage indexes were only 0.05 and0.06.Cyantraniliprole and clothianidin had second control effects.Tolfenpyrad were the weakest.