Insecticidal activity of surfactants and oils against silverleaf whitefly (Bemisia argentifolii) nymphs (Homoptera: Aleyrodidae) on collards and tomato

Abstract

The insecticidal activities of four surfactants (Cide-kick, Silwet L-77, M-Pede and APSA-80), a dishwashing detergent (New Day), a mineral oil (Sunspray oil), a cotton seed oil and a vegetable oil, alone or in combination, were tested against nymphs of Bemisia argentifolii Bellows & Perring on collards and tomato. Silwet L-77 was more effective (>95% mortality) than Cide-Kick or APSA-80 at rates from 0.25–1.00 g AI litre−1 but caused severe phytotoxicity to tender tomato leaves at all but the lowest rate. New Day dish detergent at 2.0 ml litre−1 caused mortality (95%) comparable to M-Pede insecticide soap at 10-fold greater concentration. A New Day ingredient, cocamide DEA, was considerably more active than the other ingredients or the commercial mixture. Additional surfactants added to Sunspray oil increased efficacy in some treatments, but not others. Toxic responses of 2nd- and 3rd- instar whiteflies to vegetable oil and cotton seed oil at 5.0 and 10.0 ml litre−1 plus 0.4 g AI litre−1 APSA-80 ranged from 22.1 to 79.9% and 66.3–88.7% mortality, respectively. Whitefly mortality was greater on tomato than on collard in six of seven instances when differences between host plants were significant. Our results indicate that the these surfactants and oils have good potential for controlling B argentifolii. © 2000 Society of Chemical Industry