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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #244007
Title: Behavior of Over-wintering Filbertworm (Cydia latiferreana) (Lepidoptera: Tortricidae) Larvae and Their Control with Steinernema carpocapsae

Author
item CHAMBERS, UTE - Oregon State University
item Bruck, Denny
item OLSEN, JEFF - Oregon State University
item WALTON, VAUGHN - Oregon State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2009
Publication Date: 4/1/2010
Citation: Chambers, U., Bruck, D.J., Olsen, J., Walton, V. 2010. Control of over-wintering filbertworm (Cydia latiferreana) (Lepidoptera: Tortricidae) larvae with Steinernema carpocapsae. Journal of Economic Entomology. 103(2):416-422.

Interpretive Summary: Filbertworm, Cydia latiferreana is a key insect pest associated with hazelnuts in North America. The effect of nematode rate, water volume, and orchard floor cover on nematode efficacy was determined in field trials in fall and spring (October 2007 and May 2008). Filbertworm larvae in plots with either bare soil or debris were treated with the insect-killing nematode Steinernema carpocapsae at rates ranging from 40-150 infective juveniles (IJs)/cm2 applied in 75 or 190 ml/m2 water. Filbertworm mortality was 2-11% and 50-78% in October and May, respectively. Larval mortality increased with increasing nematode concentration, but was not affected by water volume or orchard floor cover. Additionally, the ability of nematodes to infect larvae inside their overwintering cocoon as well as pupae was not significantly affected in laboratory studies using nematode concentrations between 40-200 IJs/cm2 . Furthermore, laboratory trials were performed to determine the substrate preference of final-instar filbertworm. In subsequent field trials, we tested larval preference for bare soil, grass, debris, and tree trunks as over-wintering sites. In both trials, larvae preferred organic matter, debris and grass over soil and tree trunks.

Technical Abstract: Filbertworm, Cydia latiferreana (Walsingham) (Lepidoptera: Tortricidae) is a key insect pest associated with hazelnuts in North America. The effect of nematode rate, water volume, and orchard floor cover on nematode efficacy was determined in field trials in fall and spring (October 2007 and May 2008). Sentinel filbertworm larvae in plots with either bare soil or debris were treated with Steinernema carpocapsae at rates ranging from 40-150 infective juveniles (IJs)/cm2 applied in 75 or 190 ml/m2 water. Filbertworm mortality was 2-11% and 50-78% in October and May, respectively. Larval mortality increased with increasing nematode concentration, but was not affected by water volume or orchard floor cover. Additionally, the susceptibility of larvae with and without hibernacula as well as pupae to S. carpocapsae was tested in laboratory bioassays using nematode concentrations between 40-200 IJs/cm2 . Nematode infection rate was not significantly affected by hibernacula (90-92%) and pupal stage (50-74%) compared to larvae without hibernacula (65-95%). Furthermore, laboratory trials were performed to determine the substrate preference of final-instar filbertworm. In subsequent field trials, we tested larval preference for bare soil, grass, debris, and tree trunks as over-wintering sites. In both trials, larvae preferred organic matter, debris and grass over soil and tree trunks as over-wintering sites.