Effects of Environment on Performance of Nematodes Effective use of nematodes for insect control depends on environmental conditions during and after application. Adequate moisture is the most important factor. High humidity and free water are the primary conditions for effective use of insect parasitic nematodes. Strain and species differ in temperature sensitivity. In soil applications, nematode movement to the target pest depends on conditions of the soil and thatch.
Adequate moisture is essential and pretreatment irrigation is recommended.
Irrigation may also cause soil Insects, such as white grubs, to move higher in the soil where they may be more easily found by the nematodes. Nematode movement is more extensive in sandy soils with large pore size than in clay soils. Extensive thatch accumulation may also prevent nematode penetration into the turf root zone where white grubs feed. A post-treatment irrigation may help push nematodes through the thatch layer. Nitrogen fertilizers are nontoxic to Steinernema carpocapsae , as are insecticidal soaps and wetting agents.