H. bacteriophora is a nematode (tiny worm) that attacks caterpillars and immature beetles (larvae), among other insects. It can also be used against white grubs in lawns. It actively searches out its prey in the soil, and does best in warmer soils (above 68 °F; 20 °C). This article focuses primarily on the use of Sf nematodes outside, and Sf strains that do not persist long-term after application.