Susceptibility of Bemisia tabaci biotype B to insecticides

ABSTRACT: The association between some plant pathogenic viruses and their vectors may or may not alter the action of chemical control. This study aimed at evaluating the susceptibility of viruliferous (transmitter of the begomovirus Tomato severe rugose virus, ToSRV) and aviruliferous (non-transmitter of ToSRV) Bemisia tabaci biotype B to the main insecticides registered to its control in tomato crops. Two sets of experiments were carried out with tomato plants and foliar discs of jack beans. The treatments were schemed in a factorial design of 7 (six insecticides + control) and 5 (four insecticides + control) x 2 {viruliferous (V) or aviruliferous (AV) whiteflies (WF)} and arranged in completely randomized blocks design with six and 25 replications, respectively, for tomato and jack beans. The following insecticides and concentrations were evaluated: a) tomato: acephate (100 g), clothianidin (20 g), pymetrozine (40 g), pyriproxyfen (75 mL) and thiametoxan (20 g of a.i./100 L), and diafenthiuron (800 g of a.i./300 L of solution); b) jack beans: acephate (100 g), thiametoxan (20 g), pymetrozine (40 g of a.i./100 L) and diafenthiuron (800 g of a.i./300 L). The insecticide susceptibility of whiteflies was not altered by their viruliferous condition (V or AV). The insecticides diafenthiuron (87.68%±4.96) and thiametoxam (43.94%±9.43) caused the highest mortality of whiteflies in tomatoes. In jack beans, diafenthiuron (92.01%±2.68) and thiametoxam (86,39%±2,74) caused similar mortality. Among the tested insecticides, diafenthiuron was the only one causing significant mortality of B. tabaci biotype B.