Inoculative releases of entomopathogenic nematodes and multi-year persistence across crop rotation

Native NY strains of Heterorhabditis bacteriophora, Steinernema feltiae and S. carpocapsae were inoculated into a wide variety of agricultural fields planted to alfalfa across Northern NY at the rate of 100 million IJs per acre utilizing a wide array of commercial and homemade applicators.  Prior to applications, EPNs were not detected in the fields.  EPN populations were assessed annually in each of 150+ fields for periods ranging from two to seven years.  EPN populations persisted in all fields, ranging from 20% of the soil cores tested to more than 80% in some fields.  Not only did the EPN populations persist and respond to insect invasion in the alfalfa fields, but also persisted and in some cases increased in population to insect invasion when the fields were rotated to corn and soybeans.  These data suggest that persistent EPN strains can be introduced into agricultural fields at a reduced inoculative level and their populations respond to insect invasion, reducing the impact of the invading insect.