Videotaping the Response of the Melon Aphid (Homoptera: Aphididae) to Bifenthrin Spray Deposits on Chrysanthemums

Abstract

Melon aphids, Aphis gossypii Glover, were videotaped as they walked across a leaf surface that had been sprayed with uniformly sized aqueous droplets of bifenthrin. Videotape recordings showed that the frequency with which aphids encountered droplet deposits was directly related to the droplet density (droplets per cm²). When the aphids were exposed to sparse deposits (5 drops per cm² or 2.5 per cm², 120-μm droplet in-flight diameter) irritation was apparent before physical contact with deposits, suggesting the existence of a localized vapor effect. Physical contact with deposits was not a necessary prerequisite for acquiring a lethal dose.