Submitted to: Biological Control
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/13/2008
Publication Date: 4/1/2009
Citation: Shapiro Ilan, D.I., Cottrell, T.E., Mizell III, R.F., Horton, D.L., Davis, J. 2009. A novel approach to biological control with entomopathogenic nematodes: Prophylactic control of the peachtree borer, Synanthedon exitiosa. Biological Control. 48:259-263. Interpretive Summary: The peachtree borer is a major pest of stone fruits in North America (such as peach, plums, and cherry). Currently control of this insect relies on chemical insecticide applications; due to environmental and regulatory concerns alternative approaches must be sought. In prior studies we have shown that certain species of entomopathogenic nematodes (also called beneficial nematodes) can suppress peachtree borer under field conditions when the nematodes are applied in a curative manner to established peachtree borer populations. In this study we expand upon previous research. We discovered that beneficial nematodes can also control peachtree borer populations in a preventative manner. That is, nematodes applied prophylactically, during or shortly after peachtree borer’s egg-laying period, can reduce the insect’s damage to levels similar to what is achieved with recommended chemical insecticide treatments. Additionally, based on our laboratory and field trials we have identified which nematode species is most effective at killing peachtree borer (the species is called Steinernema carpocapsae).
Technical Abstract: The peachtree borer, Synanthedon exitiosa, is a major pest of stone fruits in North America. In this study, we compared the virulence of four entomopathogenic nematode species in the laboratory. The highest virulence was observed in Steinernema carpocapsae followed by the two heterorhabditids species and lastly S. rarum. Additionally, during three consecutive years under field conditions, we determined the ability of two S. carpocapsae strains (All and Hybrid) to prophylactically protect peach trees from S. exitiosa damage. A single application of chlorpyrifos (at the labeled rate) was also made each year. Following applications in 2006 we did not detect any differences among treatments or the control (possibly due to a low and variable S. exitiosa population within the orchard). Following applications in 2005 and 2007, however, the nematode and chemical treatments caused significant damage suppression. Our results indicate that thus far S. carpocapsae is the most virulent nematode tested against S. exitiosa, and that nematodes applied in a preventative manner during or shortly after S. exitiosa’s oviposition period can reduce the insect’s damage to levels similar to what is achieved with recommended chemical insecticide treatments.