Two native Wisconsin nematodes represent virulent biocontrol agents in cranberries

Authors: FOYE, SHANE - University Of Wisconsin; Steffan, Shawn

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2019
Publication Date: 7/25/2019
Citation: Foye, S., Steffan, S.A. 2019. Two native Wisconsin nematodes represent virulent biocontrol agents in cranberries. Biological Control. 138. Article 104042. https://doi.org/10.1016/j.biocontrol.2019.104042.
DOI: https://doi.org/10.1016/j.biocontrol.2019.104042

Interpretive Summary: The cranberry girdler is a ubiquitous pest of Wisconsin cranberries, and biological control agents are in demand for this pest. A bio-insecticide comprised of two native Wisconsin nematodes has been deployed against this pest, and the results suggest that the nematodes are highly effective. The virulence demonstrated following field applications indicates that the bio-insecticide holds promise as a new tool for US cranberry growers.

Technical Abstract: In Wisconsin, two nematode species Heterorhabditis georgiana (Nematoda: Heterorhabditidae) and Oscheius onirici (Nematoda: Rhabditidae) have been used to control the red-headed flea beetle Systena frontalis Fabricius (Coleoptera: Chrysomelidae) on cranberry farms. Therefore, there is an interest in using the nematodes to control another pest afflicting cranberry farms, the cranberry girdler Chrysoteuchia topiaria Zeller (Lepidoptera: Crambidae). It is unknown if a single nematode species or a combination of the two will be better for controlling the girdler. In field plots, treatments containing H. georgiana were associated with an 83% suppression versus control plots. Treatments consisting of just O. onirici were not associated with a reduction in girdler abundance. The nematode combination was no different from a treatment consisting of just H. georgiana, therefore, H. georgiana alone is responsible for controlling the cranberry girdler.