Various factors affecting the rate of honeydew deposition by the greenbug (Toxoptera graminum (Rond.)) and the spotted alfalfa aphid (Therioaphis maculate (Buck.)) were studied and the reactions of the two species compared. A method was developed whereby honeydew droplets from one aphid feeding for a '24-hour period on a plant part were caught on the bottom or sides of plastic cages. The rate of honeydew deposition was affected significantly in both the greenbug and the spotted alfalfa aphid by: (1) changes in temperatures; (2) different plant parts as feeding sites (leaf, stem, petiole); (8) different varieties of plants; and (4) the amount of light reaching the host plant and feeding site. The following factors were found to affect significantly the rate of honeydew deposition by the greenbug: (1) the area of feeding on a Reno barley leaf; (2) feeding on leaves yellowed by age; (8) reduced moisture to host plant. Changes in the following factors or conditions did not affect significantly the rate of honeydew deposition by the spotted alfalfa aphid: (1) reduced moisture to host plant or (!t) distance of leaves from growing point. The rate of honeydew deposition on Reno and Dicktoo barley and Pawnee wheat exceeded that found on the alfalfa varieties studied. This implies that the problems resulting from honeydew might be as great on barley and wheat as on alfalfa if it were not for the different methods in cultivation and harvesting time. The rate of honeydew deposition was found to be influenced almost directly in proportion to the known amount of resistance found in the host plants used. This condition suggests the possibility that the rate of honeydew deposition by aphids may be used to measure the degree of resistance of host plants to aphids, the rate of ingestion of plant material, and to serve as a crude measure of the metabolic activity of the insect.
Document Type: Research Article
Publication date: June 1, 1959
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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.