Sublethal Effects Of Chlorpyrifos On Bactrocera Dorsalis

The oriental fruit fly,Bactrocera dorsalis?Hendel?,is an important and quarantine pest in the world.Chlorpyrifos is a kind of highly effective and low toxic organophosphorus pesticide,which commonly used to prevent Bactrocera dorsalis.In this study,we used the method of artificial diet mixed with poison to study the determination of chlorpyrifos in Luoyang population and the sublethal effect of chlorpyrifos on the 2rd adult of Bactrocera dorsalis,It is helpful to understand the control effect and biological effect of citrus fruit fly.The aim of this study was to provide scientific basis for the prevention and control of the resistance to chlorpyrifos.The results of this study are as follows:?1?The toxicities of four insecticides to the fruit fly was evaluated from large to small:Chlorpyrifos >Cothianidin> Cyfluthrin > Spirotetramat > Methoxyfenozide.?2?Change of LC₅₀ values in 15 adults of different day age: 1-30 day age increased firstly,then 30-35 day age tends to be stable,after 35 days of age,there was a downward trend.The adults of the same sex and different age were significantly different,the adults of the same age and different gender showed little sensitivity difference:the LC₅₀ value of the same day old male was lower than that of female's LC₅₀,And the results showed that male adults were more sensitive to chlorpyrifos than female adults.But there was no similar change rule of egg production?3?Effects of sublethal doses of chlorpyrifos on the fecundity of Bactrocera dorsalis' s parental adults have something with the sublethal doses.The adult period and hatching rate showed dose effect,and with the increase of sublethal dose of chlorpyrifos,it was significantly shorter and lower?4?Effects of sublethal doses of chlorpyrifos on the fecundity of Bactrocera dorsalis' s F1 generation don't go with the continuation of generation.Compared with the control group,there were significant differences in F1 male adult.LC₂₅ group increased 1.8mg than the control group and the difference was significant.The cause of pupa weight is likely that weak or dead larvae pupation is unsuccessfully,strong and healthy larvae retained and pupation successfully.This shows that sublethal doses of LC₂₅ on the effect of Bactrocera dorsalis is bigger than lethal dose LC₁₀.It was not found that sublethal doses of chlorpyrifos significantly affected the amount,the pupal period,the first mating day,mating frequency,etc.of F1 generation.In summary,In Luoyang,Bactrocera dorsalis is still sensitive to chlorpyrifos.Sublethal doses of chlorpyrifos reduced the reproductive capacity of Bactrocera dorsalis,and plays a certain role in controlling the increase of population.The next step is to study the sublethal effects of chlorpyrifos on the field population of Bactrocera dorsalis.