Direct and indirect impact of selected insecticides to Delphastus Delphastus (Coleoptera: Coccinellidae) a biological control agent of whiteflies Bemisia tabaci biotype B

Delphastus catalinae (Coleoptera: Coccinellidae) is a predator of whiteflies that is used in tropical and semi-tropical crops as well as commercial vegetable greenhouses. Previous studies on D. catalinae showed they are capable of reducing whitefly (Bemisia tabaci - Hemiptera: Aleyrodidae) populations but often need to be used in combination with insecticide applications. A significant limitation is that few studies exists showing the insecticide effect on the beetles. The aim of this study was to test the susceptibility of D. catalinae to three insecticides with different mode of action commonly used for whitefly management on tomato. The insecticides used were (Safari: dinotefuran; Merit 2F: imidicloprid; Molt-X: azadirachtin; ). We recorded the mortality of the beetle through direct and indirect exposure. When the insecticides were applied indirectly the beetles survived better the application of the insect growth regulator Molt-X. The rank tests for homogeneity indicate a significant difference between the treatments,(P= 0.0001 for the both log-rank and Wilcoxon tests).