Methods of Testing Chemicals on Insects

Abstract

There are several ways of administering a chemical to an insect. A commonly employed method is topical application, where the insecticide is dissolved in a relatively nontoxic solvent, such as acetone, and small, measured droplets are applied at a chosen location on the body surface. Topical application as is practiced today was made possible by the invention of the micrometer-driven syringe (Trevan 1922) and the use of continuous carbon dioxide anesthesia (Williams 1946). The advantages of this method are:

• 1. The high degree of precision and reproducibility that can be attained.

• 2. The large number of tests that can be performed in a relatively short time.

• 3. The small number of insects (10-20) required per replication.

• 4. The simple and inexpensive equipment needed.

• 5. The very small amount of chemicals and solvents used.

• 6. The fact that the LD50 values obtained for any species are reasonably constant and reproducible from laboratory to laboratory, provided that identical conditions of testing are maintained.