Populations of Tetranychus urticae Koch were studied to determine their influence on photosynthesis of leaves of potted 'Franklin' and 'Red Delicious' apple trees. Nine days after treatment, 15, 30, and 60 mites/leaf had reduced net photosynthesis values 26, 30, and 43% below check Franklin leaves. Significant negative correlations were found between photosynthesis and leaf color values. On Red Delicious leaves, initial population levels of 15 and 30 mites/leaf reduced photosynthesis as early as 7 days after treatment. Significant negative correlations were found among photosynthesis, mite populations, and color values. Observers could not detect visible yellowing of leaves even when there were reductions in net photosynthesis.
Document Type: Research Article
Publication date: August 1, 1975
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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.