The requirements of insecticide formulations for use against. the desert locust, Schistoeera gregaria (Forskål), are described. DDVP is shown to be more toxic and quick acting than other insecticides in common use (LD50's: DDVP 1.8-4.3, diazinon 4.7, and BHC (gamma isomer) 9.0 pg./g. of body weight). The toxicity of DDVP in oil solution by contact action decreased when it was applied in concentrated form (LD50's: 1.8 in 3.5- ,5.0% wt./vol. solution and 3.3 pg/g. of body weight ill 35% wt./\'ol. solution in the distillates KEB or LPD), and was found to be very dependent on the exact nature or the solvent used. The rate or evaporation of the insecticide was determined at 30° C.; free-falling lOO-micron droplets of pure DDVP were esti- mated to lose nearly 1% of their active ingredient per metre of fall. Droplets of DDVP in dioetylphthalate and dutrex 3 lost the active ingredient at a faster rate. The vapour toxicity also was determined (CT50=1.0 g. sec./m.3) and shown to be of little importance compared with the toxicity of sprays (CT50= 1.6 X 10-3 g.sec./m.3). DDVP was found to be partially cumulative (JD50increased by one third when dose was applied in two halves separated by a 72-hour interval) and 1.8 timesmore toxie when applied to the wings than to the abdomen of the desert locust. Used in dilute solution,DDVP would have to compete in price with the the cheaper BHC and aldrin. The properties of the concentrates do not suggest that DDVP would find generaluse in locust control until means can be round to reduce its rate of emporation.
Document Type: Research Article
Publication date: December 1, 1963
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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.