Two native Wisconsin nematodes represent virulent biocontrol agents in cranberries

In 2015 and 2016, surveys of entomopathogenic nematodes were conducted in the wild cranberry habitats of Wisconsin. The purpose of the survey was to find a biological control agent for control of insect pests of cranberries. Two nematodes, Oscheius onirici Torini (Rhabditida: Rhabditidae) and Heterorhabditis georgiana Nguyen (Rhabditida: Rhabditidae), were collected in this survey. Laboratory trials show that applications of either O. onirici or H. georgiana resulted in 75% and 65% mortality rates, respectively, when applied to sparganothis fruitworm Sparganothis sulfureana Clemens (Lepidoptera: Tortricidae) larvae. In replicated field trials, both nematode species were also shown to significantly suppress the redheaded flea beetle, Systena frontalis Fabricius (Coleoptera: Chrysomelidae) populations. Collectively, these findings suggest that these nematodes may be promising bio-insecticides for cranberries.