Bacillus thuringiensis variety aizawai, sold under the product name Certan, is used as an insecticide against wax moth caterpillar infestations in honeybee hives. These two bacteria offer only limited usefulness in Oklahoma where Japanese beetles are not found. Annual white grubs are not susceptible, or only slightly susceptible, to these bacterial insecticides. Another bacterium that has been toxic to larvae of some mosquito species in laboratory tests is Bacillus sphaericus. However, it has not had promising field test results and is still in development.
Entomogenous nematodes are multicellular roundworms.
It is not the nematodes themselves, but bacteria associated with them, that actually kill insects. Entomogenous nematodes and their associated bacteria are considered nontoxic to plants and mammals. Steinernema feltiae, used against larvae of a wide variety of soil-dwelling and boring insects, is the main nematode species available at retail in the United States. Because of moisture requirements, it is effective primarily against insects in moist soils or inside plant tissues. Prolonged storage or exposure to extreme temperatures before use may kill or injure the nematodes.