The egg cases may be found on tree twigs and in the field. Each case will produce hundreds of young. These wasps lay their eggs on the tomato hornworm, eventually killing it and producing more beneficial wasps in the process. They are environmentally safe and harmless to humans and all other warm blooded animals, nor will they harm fish or plants. Apply in spring and fall when the soil contains insect larvae.
Results usually take two to three weeks.
Most gardeners will need to apply each year. Each spray will introduce hundres of millions of nematodes. Birds Don't forget that birds are beneficials - insectivores eat their weight in insects several times a day. Other beneficial birds in the local area are bluebirds, bobolinks, meadowlarks, doves, field sparrows, purple martins, swallows, kingbirds, black phoebes, titmice, Baltimore orioles, and woodpeckers. There are many more very good predators and parasites in the world of insects.