The effects of various insecticides on lettuce physiology and productivity were investigated in the field, Measurements of plant photosynthesis and stomatal conductance rates were taken with a dual-isotope porameter. Methyl parathion and permethrin had the greatest significant effects on photosynthesis and stomatal conductance rates. Lettuce plants receiving weekly treatments of methyl parathion produced smaller lettuce heads as compared with those treated with other insecticides and untreated check plants. Results indicate that the use of the dual-isotope porometer has great potential in monitoring subtle changes in plant photosynthesis and stomatal conductance rates caused by pesticides. The potential development of "pesticide thresholds" which would indicate the maximum safe number of pesticide applications permissible on designated crops was suggested.
Document Type: Research Article
Publication date: August 1, 1982
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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.