Laboratory Evaluation of Chemosterilants Against the Adult House Fly, 1982

Abstract

Abstract Mixed sexes of adults from an insecticide-resistant laboratory strain are fed exclusively after emergence on fly food (6 parts sugar, 6 parts powdered nonfat dry milk, and 1 part powdered egg yolk) containing a 1% concentration (wt/wt) of the candidate chemosterilant. The treated diet is prepared by adding 10 ml of a solution or suspension of the chemical in a volatile solvent to 10 g of fly food in a small container. The solvent is allowed to evaporate for 4-6 h, then the fly food is repulverized. The container of treated food and a container of water are placed in a cage with 100 newly emerged adult flies. After 3 days, the flies are observed to note any mortality caused by the compound. When flies were 6-7 days old, moist CSMA larval-rearing medium in a container is placed in the cage to stimulate oviposition. If no eggs are laid, the oviposition medium is offered again at 1-2 day intervals until it has been offered 3 times or the flies have oviposited. After the medium has been in the cage for 4-6 h, it is removed and the egg masses are transferred to a container of water and thoroughly mixed. A random sample of 100 eggs is placed on a small piece of wet black cloth; the cloth is then place on moist CSMA medium in a rearing container. After 2 days, the eggs are examined and the percent hatch is determined. The resulting larvae, if any, crawl from the cloth into the rearing medium. The medium is examined about a week after oviposition to determine the number of larvae that develop to the pupal stage. If more than 5 pupae are observed, evaluation of the compound is discontinued. All tests are conducted in duplicate. Cages of flies handled in the same manner but exposed to untreated fly food only are used as controls.