Oviposition by Bemisia argentifolii (Homoptera: Aleyrodidae) on Tomato: Effects of Leaf Factors and Insecticide Residues

Abstract

Ovipositional preference based on leaf age, height, surface orientation, and the presence of insecticidal residues was determined for Bemisia argentifolii Bellows & Perring, formerly B. tabaci (Gennadius), biotype B. Two-leaflet simulated plants were used to study the effects of leaf age, height, and surface orientation in choice and no-choice tests. Whiteflies preferred young leaves to old leaves for oviposition, although this preference was overridden by reversing normal leaf position, that is, placing old leaves high and young leaves low. Preference for the abaxial leaf surface was not increased by reversing orientation, although oviposition on the adaxial surface was increased by this procedure. The effects of insecticide residues on oviposition were studied by exposing whiteflies to individual insecticide-treated tomato leaves. Interactions among leaf ages, leaf heights, and insecticide residues were shldied on simulated plants and individual leaves. The fewest eggs were found on young leaves treated with mineral oil, followed by pyrethroid, insecticidal soap, and sucrose and glucose esters in choice and no-choice tests. The effects of leaf age and leaf height were overridden by repellency to residues of bifenthrin and mineral oil. Repellency to residues might be used to improve the efficacy of insecticides by manipulating whitefly distribution within the canopy.