Trichogramma

a genus of ichneumon flies of the order Hy-menoptera that parasitize insect eggs. The flies are small, measuring 0.3–0.6 mm, and range in color from pale yellow to brownish black. They parasitize 215 species from six orders, mainly moths and hymenoptera. The female lays 25–150 eggs (usually 40–60), depositing between one and 40 in each egg of the host, depending on the size of the host’s egg. Under favorable conditions, development lasts approximately two weeks.

In the USSR, T. evanescens is the most important species, as it parasitizes more than 100 species of moths, including the grain moth Nemapogon granellus, Barathra brassicae, Argotis segetum, the corn borer (Pyrausta nubilalis), and the codling moth (Laspeyresia pomonella). The insect sometimes destroys 90–100 percent of the eggs of destructive species. T. pallida is a parasite of the codling moth and some leaf roller moths, and T. pini feeds on eggs of the pine moth.

The most important species in the USA is T. minutum, which is used to control the codling moth, Grapholitha molesta, the sugarcane borer (Diatraea saccharalis), and Chilo simplex.

Insects of the genus Trichogramma have long been used to control crop pests because they are easy to raise in a laboratory and are polyphagous. However, despite a number of successful instances when the insects were employed, lasting positive results have not yet been achieved.