Sublethal Effects Of SYP-9080on Eotetranychus Kankitus (Ehara) And Neoseiulus Cucumeris(Oudemans)

Eotetranychus kankitus (Ehara) is one of the major pest in Chinese citrus production areas, and the Neoseiulus cucumeris (Oudemans) is one of the introduced predatory mites which can control citrus spider mites. The study focused on the susceptibility and sublethal effects of the novel insecticides SYP-9080on E. kankitus and N. cucumeris. The main contents and results are as follows:1. Toxicity of SYP-9080to E. kankitus and N. cucumeris.Toxicity of SYP-9080to the adults and eggs of E. kankitus and N. cucumeris were determined. The results indicated that LC50of SYP-9080using the leaf residue method to E. kankitus was recorded as46.3750(ag/mL and Slide-dip method was23.8870μg/mL; LC50of SYP-9080to N. cucumeris was400.289μg/mL; and there were no secondary poisoning phenomenon when N. cucumeris feed with E. kankitus which was treated with SYP-9080; Toxicity of SYP-9080to the eggs shows that SYP-9080has no acaricidal activity.2. The effect of the sublethal dosage of SYP-9080on experimental population to E. kankitus and N. cucumeris.The effect of experimental population of E. kankitus’and N. cucumeris’adults treated with the sublethal dosage of LC15and LC30of SYP-9080were studied. Eggs treated with dosage of common usage were also studied. The results indicated that after E. kankitus’s and N. cucumeris’s adult had been determined by sublethal dosage of SYP-9080,the longevity and average ovipositor quantities were dramaticlly lower than the control, the second generation eggs’hatchability reduced but not significance. Fl’s developmental period and the life span were significantly decreased, and the Ro、λ、 rm were observably reduction contrast with the control; the developmental period and the life span extended but not significant when N. cucumeris were treated by SYP-9080, so SYP-9080may disturb the generation of E. kankitus population growth rate but not for N. cucumeris. After determined by the field commonly using dosage of SYP-9080to the eggs of E. kankitus and N. cucumeris, there were some influence on their developmental period, the developmental period of E. kankitus were lengthened as the increase of the dosage of SYP-9080,but there were no significant difference of the N. cucumeris, and two kinds of eggs’life span and oviposition amount were significantly reduced.3. Effects of feeding N. cucumeris with E. kankitus which were treated with sublethal dosage of SYP-9080.Effects of feeding N. cucumeris with E. kankitus which were treated with sublethal dosage of SYP-9080were studied.The results show that there were some influence on E. kankitus which were treated with the sublethal dosage SYP-9080appeal to N. cucumeris. the most interaction attractive was LC15treatment group,and then the control and LC30;preying on E. kankitus which were treated with SYP-9080, the N. cucumeris longevity,eggs were significant reduced, but hatch rate has no difference; that explicate that there were some explicate on N. cucumeris to ate E. kankitus which were treated with SYP-9080; the predatory numbers of the N. cucumeris to E. kankitus which retreated by sublethal dose were reduced and dose related, but when the prey density reached a certain amount, the predatory numbers retreated by LC30would higher than LC30, the parameters of the model changed, the maximal predatory capacities were reduced, and the handling time was prolonged.4. Effects of sublethal doses of SYP-9080on the predatory function of N. cucumeris to E. kankitus.Influence of the sublethal dose treated with SYP-9080to predatory response of N. cucumeris to E. kankitus was studied. The results showed that the predatory numbers of the N. cucumeris treated with the sublethal dosage of SYP-9080to E. kankitus of difference developmental stages were reduced,and in the same dosage, the predatory numbers of N. cucumeris were deference, and the larvas> nymphs> female> eggs; the parameters of the model changed, the maximal predatory capacities of N. cucumeris that pretreated with sublethal dose of SYP-9080were decreased, the handling time was prolonged, the predatory rates were declined, and the searching capability were weakened than that of control. These findings suggested that insecticides at sublethal level had harmful influence on the predation of N. cucumeris.