Location: Fruit and Tree Nut ResearchTitle: Virulence of entomopathogenic nematodes to plum curculio, Contrachelus nenuphar: Effects of strain, temperature, and soil type Author
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2012
Publication Date: 8/15/2012
Citation: Shapiro Ilan, D.I., Leskey, T.C., Wright, S.E. 2012. Virulence of entomopathogenic nematodes to plum curculio, Contrachelus nenuphar: Effects of strain, temperature, and soil type. Journal of Nematology. 43:187-195. Interpretive Summary: Plum curculio is a key pest of various stone and pome fruts such as peaches, plums, cherries, apples, and pears. Due to environmental concerns new safe and effective control methods must be developed as alternatives to chemical insecticides. Beneficial "entomopathogenic" nematodes, which are natural bioinsecticides, may be the solution. In the laboratory, we compared 13 different strains (kinds) of beneficial nematodes for their ability to kill plum curculio. We discovered that three species (called Steinernema feltiae, Steinernema rarum, and Steinernema riobrave) were the most effective in suppressing this dangerous pest. In future research, field tests will be used to further narrow down the most suitable nematode species for plum curculio control. Based on this research, beneficial nematodes may be incorporated into a sustainble integrated pest management program for plum curculio.
Technical Abstract: The plum curculio, Conotrachelus nenuphar, is a major pest of stone and pome fruit (e.g., apples, pears, peaches, cherries, etc.). Entomopathogenic nematodes (Steinernema spp. and Heterorhabditis spp.) may be used to control the larval stage of C. nenuphar following fruit drop. Indeed, certain entomopathogenic nematodes species have previously been shown to be highly effective in killing C. nenuphar larvae in laboratory and field trials. In field trials conducted in the southeastern USA, Steinernema riobrave has thus far been shown to be the most effective species. However, due to lower soil temperatures, other entomopathogenic nematode strains or species may be more appropriate for use against C. nenuphar in the insect’s northern range. Thus, the objective of this study was to conduct a broad screening of entomopathogenic nematodes. Under laboratory conditions, we determined the virulence of 13 nematode strains (comprising nine species) in two different soils (a loam and clay-loam) and three different temperatures (12, 18, and 25 °C).Superior virulence was observed in S. feltiae (SN strain), S. rarum (17 C&E strain), and S. riobrave (355 strain). Promising levels of virulence were also observed in others including H. indica (HOM1 strain), H. bacteriophora (Oswego strains), S. kraussei, and S. carpocapsae (Sal strain). In future research, field tests will be used to further narrow down the most suitable nematode species for C. nenuphar control.