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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #212078
Title: Control of plum curculio, Conotrachelus nenuphar with entomopathogenic nematodes: effects of application timing, alternate host plant, and nematode strain

Author
item Shapiro Ilan, David
item MIZELL, RUSSELL - UNIV OF FLORIDA
item Cottrell, Ted
item HORTON, DAN - UNIV OF GEORGIA

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2007
Publication Date: 12/22/2007
Citation: Shapiro Ilan, D.I., Mizell, R.F., Cottrell, T.E., Horton, D.L. 2007. Control of plum curculio, Conotrachelus nenuphar with entomopathogenic nematodes: effects of application timing, alternate host plant, and nematode strain. Biological Control. 44:207-215.

Interpretive Summary: The plum curculio is a key insect pest of pome and stone fruits (apples, peaches, plums, cherries, etc.). Research aimed at finding safe and effective methods of control for this pest is warranted. In prior research, we established that soil applications of an environmentally friendly insect-killing nematode called Steinernema riobrave can effectively suppress immature (larval) stages of plum curculio in peach orchards. In this study, we further investigated the potential of using nematodes to control plum curculio by evaluating 1) field efficacy of late-term nematode applications targeting plum curculio adults, 2) control of plum curculio larvae in an alternate host, i.e., wild plum, and 3) laboratory virulence (killing power) of different nematode strains. In 2004 and 2005, late-term nematode applications targeting adult plum curculio failed to cause measurable control. However, when targeting the larval stage in a wild plum thicket one nematode strain caused 100% control (both years), and another strain caused 98.6% and 87.9% control in 2005 and 2006, respectively. Applications in alternate hosts could reduce plum curculio immigration into the orchard. Laboratory experiments confirmed that some nematode strains are more effective than others, and suggested that immature plum curculio are more susceptible to nematodes than the adult insects. We conclude that soil applications with insect-killing nematodes can cause high levels of plum curculio control in peach or alternate hosts, but timing of application and the choice of nematode species or strain can be important.

Technical Abstract: Plum curculio, Conotrachelus nenuphar, is a key insect pest of pome and stone fruits. In prior research, we established that soil applications of Steinernema riobrave in peach orchards that target C. nenuphar, larvae can result in high levels of control (78-100%). In this study, we further investigated the potential of using entomopathogenic nematodes to control C. nenuphar. In 2004 and 2005, late-term soil applications of S. carpocapsae and S. riobrave in a peach orchard (targeting the adult stage C. nenuphar) failed to cause any measurable control. In field tests targeting C. nenuphar larvae in a wild plum thicket, S. riobrave (355 strain) caused 100% control (both years), and S. riobrave (3-8b strain) caused 98.6% and 87.9% control in 2005 and 2006, respectively. Applications in alternate hosts could reduce C. nenuphar immigration into the orchard. Laboratory experiments with S. carpocapsae and S. riobrave confirmed that some nematode strains are more effective than others, and suggested that immature plum curculio are more susceptible to nematodes than the adult insects. We conclude that soil applications with entomopathogenic nematodes can cause high levels of C. nenuphar control in peach or alternate hosts, but timing of application and the choice of nematode species or strain can be important.