Control of thrips (Enneothrips flavens Moulton.) with synthetic and biological insecticides in different peanut genotypes

In peanut, pests are controlled by application of insecticides throughout the crop cycle, boosting production costs. This study compared the control of thrips ('Enneotrhips flavens' Moulton) in 10 peanut genotypes by biological and synthetic insecticides in the field in tropical area in Southeastern Brazil (21 degrees13'29.9''S 48 degrees54'33.0''W). The experiment was arranged in a randomized block, 10 x 3 factorial design with three replications. The first factor corresponded to 10 peanut genotypes and the second to different insecticides (synthetic, biological and control). The plants were evaluated 36, 44, 51, 59, 65, 72, and 79 days after sowing to determine the number of thrips individuals and the damage on leaflets caused by 'E. flavens'. The plant height (cm), branch length (cm) and pod yield (kg ha-1) were also determined. The data were subjected to analysis of variance and averages compared by Tukey's test. In prior evaluation carried out before the start of the applications of insecticides (25 DAS), natural infestation of thrips was observed in all genotypes. The genetic variability of lines L. 386 and L. 314 and cultivar IAC 113 was not significant, whereas yield difference was not observed among treatments of insecticides and control, showing tolerance to 'E. flavens'. The synthetic insecticide Engeo Pleno showed of 39% higher efficiency (as average) for controlling thrips in peanut. The insecticides Beauveria bassiana (Bals.) (AUIN) and Metarhizium anisopliae (Metch.) (GR-INN) have potential to control 'E. flavens' in peanut, but further studies are needed to better define the application date and products doses.