Insecticide Resistance Monitoring Of Thrips Palmi Karny And Transmission Properties Of TSWV In Shandong Province

Thrips palmi Karny is an important pest insect on vegetables, and causes huge treatment on vegetables in our country. We established a stable population of T. palmi, studied the insecticide resistance levels of T. palmi by using leaf tube residue method and the transmission characteristics of T. palmi on tomato spotted wilt virus. The results are as follows:1. In this study, we implemented the large-scale breeding of T. palmi, and established a stable population, under 25±1 °C, 70±5% RH, L : D= 16 : 8 h. With this rearing conditions, the survival rate of 1st-instar nymph、2nd-instar nymph、pre-pupa and pupa were 91.00%, 62.00%, 98.00%, 89.00% respectively. The adult female average egg-laying period was 16.9 d which the fecundity per one was 55.75 eggs and the daily oviposition per one was 2.79 eggs. The population parameters were obtained such as the intrinsic rate of natural increase(r=0.126), net reproductive rate(R0=11.15), the mean generation time(T=19.13), doubling time(DT=5.50d) and finite rate of increase(λ=1.131).2. The resistance of T. palmi, collected from four vegetable production areas of Shandong province to 7 insecticides was evaluated by using leaf tube residue method.The results which were compared by LC50 showed that the toxicity orders of these insecticides were spinosad > emamectin benzoate > imidacloprid > thiamethoxam > pymetrozine > lambda-cyhalothrin > phoxim. T. palmi populations collected from Jinan, Tai’an and Liaocheng districts were sensitive to spinosad. The Shouguang population exhibited low resistance to emamectin benzoate(resistance ratio was 9.92). Tai’an, Liaocheng population decreased sensitivity and Jinan population was sensitive to emamectin benzoate. The sensitivity of Liaocheng population to thiamethoxam decreased slightly(resistance ratio was 10.38), and the rest of the population were at the sensitive state. For imidacloprid, Shouguang population reached a low level of resistance(resistance ratio was 8.28). Liaocheng, Ji’nan population resistance were emerging to imidacloprid, and only Tai’an population was still at the sensitive level. The Shouguang population had low resistance to pymetrozine, while the rest of the population decreased sensitivity. The resistance ratio of Shouguang population to phoxim was 3.90. All populations were susceptible to lambda-cyhalothrin.3. RT-PCR technique was used to detect the acquisition efficiency and the inoculation efficiency of Thrips palmi. The results showed that the average acquisition efficiency of the nymph and adult was 100% and(13.33±1.67)% respectively. When the numph was feed on the infected leaves of 48 h, the nymph could not effectively transmit TSWV.