Mosquito Pest Management

Bulletin 641

Pesticide Toxicity

The toxicity of a pesticide is expressed through the terms "oral" and "dermal" LD₅₀. The lower the LD₅₀ value, the more toxic the material. LD₅₀ is the dosage of poison that kills 50 percent of the test animals (usually rats or rabbits) with a single application of the "pure" pesticide for a given weight of animal (mg/kg of body weight). Oral LD₅₀ is the measure of the toxicity of pure pesticide when administered internally to test animals. Dermal LD₅₀ is the measure of the toxicity of pure pesticide when applied to the skin of test animals.

LD₅₀ Values of Mosquito Insecticides

Insecticide Oral LD50 (mg/kg) Rat Dermal LD50 (mg/kg) Rabbit Moderately Toxic carbaryl (Sevin) 246 --- chlorpyrifos (Dursban, Empire, Mosquitomist) 96 2000 cypermethrin (Cynoff, Cyper-Active, Vikor) 250 >2000 deltamethrin (Suspend) 129 >2000 naled (Dibrom) 92 360 permethrin (Biomist) 430 >2000 propoxur (Baygon) 50 >5000 (Rat) tralomethrin (Saga) 100 >2000 Slightly Toxic cyfluthrin (Tempo) 826 >5000 Relatively Non-Toxic Bacillus thuringiensis Berliner var. israelensis >5000 >2000 malathion (Fyfanon) 5500 >2000 (Rat) methoxychlor (Marlate) 6000 --- methroprene (Altosid) >34,600 >3000 pyrethrins 1500 >1800 (Rat) resmethrin (Scourge) >2500 >3000 (GP*) temephos (Abate) 4204 2000 * GP= Guinea Pig Source: Farm Chemicals Handbook ’98, Meister Publishing Company, Willoughby, OH 44094-5992.

Metric Conversion Table

English Multiply By Metric Square foot (sq. ft.) 0.09 Square meter (m2) Acre (A) 0.4 Hectare (ha) Pound 0.45 Kilogram (kg) Tablespoon (Tbsp.) 15 Milliliter (ml) Fluid ounce (fl. oz.) 30 Milliliter (ml) Pint (pt.) 0.45 Liter (l) Gallon (gal.) 3.8 Liter (l)

References

Bennett, Gary W. 1978. Mosquito Control in Small Areas. Pest Control Technology Magazine. June Edition.

Carpenter, S.J. and LaCasse, W.J. 1955. Mosquitoes of North America (North of Mexico). U.Calif. Press Berkeley and Los Angeles.

Davidson, Ralph H. and Lyon, William F. 1987. Insect Pests of Farm, Garden and Orchard. 8th Edition. The Ohio State University. John Wiley & Sons, 605 Third Avenue, New York, NY 10016.

Lyon, William F. and Collart, Michael. 1993. Mosquitoes. HYG-2058-93, The Ohio State University Extension, Columbus, Ohio 43210.

Rings, Roy W., et. al. 1968. Ohio Mosquito Control Manual. Ohio Cooperative Extension Service (OSU) and the Ohio Department of Health. Columbus, Ohio 43210.