Translaminar activity of abamectin was studied during 1992-1994 on apple. Malus X domestica Borkhauser, and pear, Pyrus communis L. Field-aged residues were bioassayed from the top or bottom leaf surface of apple and pear after atomizer application to the top or bottom surface, or handgun application to both surfaces. Tetranychus urticae Koch was used as the test organism with the exception of 1 experiment, which included Panonychus ulmi (Koch). Abamectin showed little translaminar activity on apple regardless of the leaf surface to which it was applied. There was preferential absorption by the bottom leaf surface, which resulted in higher levels of mortality for mites feeding on the bottom surface when this was also the treated surface (bottom/bottom [surface treated/surface assayed]). Mortality caused by other combinations (bottom/top, top/bottom, top/top) was minimal. Mortality from assays conducted on the bottom surface was also higher in the apple/handgun experiments. Translaminar activity was greater on pear, but primarily through the bottom leaf surface. The degree of translaminar movement was sufficient to cause comparable levels of mortality on both the top and bottom surfaces when applied solely to the bottom surface. There was no difference in mortality between the 2 mite species when assayed on the same leaf surface. However, based on control mortality and runoff, the bottom leaf surface of apple and pear is a more favorable habitat for T urticae than the top surface, whereas the opposite is true for P ulmi. The implications of mite host preference, feeding behavior, and differential absorption of abamectin are discussed.
Document Type: Research Article
Publication date: April 1, 1997
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.