Eficiência de inseticidas químicos e associação com o fungo Isaria javanica sobre ninfas e adultos de mosca-branca
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2017-02-21
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Universidade Federal de Goiás
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The main damage of whitefly Bemisia tabaci biotype B on beans is virus transmission such as Bean golden mosaic virus (BGMV) and Cowpea mild mottle virus (CpMMV). Different insecticides mechanisms of action, use of selective molecules and alternative methods of control are important techniques for management of this insect. Therefore, this study was conducted to test the efficiency of chemical insecticides on mortality of whiteflies adults and CpMMV transmission on BGMV-resistant transgenic common bean; and to verify the combination of chemical insecticides in sublethal doses with the entomopathogeni fungus Isaria javanica on control of B. tabaci nymhps in commom bean. In first part of the study two experiments were conducted with seed treatments, one with foliar application and another with the combination with seed treatment and foliar application. Experiments were conducted in screenhouse. In first experiment with seeds treatment thiametoxam FS at 300, 500, 700 mL and imidacloprid+thiodicarb FS at 500, 600 e 800 mL were tested. In second experiment were used higher doses of thiametoxam FS (500, 700 e 900 mL) and imidacloprid+thiodicarb FS (600, 800 e 1.000 mL). In foliar application were evaluated the insecticides thiamethoxam+cyantraniliprole WG and flupyradifurone SL at 500 e 750 mL ha-1, thiamethoxam + lambda-cyhalothrin SC and thiamethoxam WG both at 300 mL ha-1. In combination of seed treatment and foliar application the treatments were plants treated only with seed treatment or with ST following 1, 2, 3 or 4 foliar applications with different insecticides at five-days intervals. On second stage, at laboratory the compatibility of spiromesifen and buprofezin with I. javanica was observed. Different insecticides concentrations (12.5; 25; 50 and 100 ppm) were added to conidia suspension. Germination of conidia, mycelial growth and conidial production were evaluated. On screenhouse were determined: 1) the sublethal (CL25) doses of insecticides spiromesifen and buprofezin to 2nd ínstar whitefly nymphs; 2) the bio-efficacy of different isolates of I. javanica to 2nd ínstar whitefly nymphs and 3) the effect of the combination between spiromesifen and buprofezin with I. javanica on control of 2nd ínstar whitefly nymphs. Nymphal mortality and sporulation on cadavers (2 and 3) were evaluated. As result was observed that thiametoxam + ciantraniliprole WG and flupiradifurone SL applied in foliar application resulted in higher mortality of whitefly adults. ST added 3 or 4 foliar application proportioned the highest mortality and reduction on CpMMV transmission. Insecticides are efficient on B. tabaci control; however, it does not avoid the virus transmission. The combinations of ST added 3 or 4 foliar application reduce the CpMMV on 50%. All I. javanica isolates caused nymphal mortalities. Spiromesifen and buprofezin were compatible with I. javanica. Additive and synergistic effects were observed. A management program of whitefly is important to reduction of CpMMV incidence on BGMV-resistant transgenic common bean. Besides, the combination of selective chemical insecticides and I. javanica on B. tabaci might increase the success of control.
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SANTOS, T. T. M. Eficiência de inseticidas químicos e associação com o fungo Isaria javanica sobre ninfas e adultos de mosca-branca. 2017. 75 f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Goiás, Goiânia, 2017.