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Title: Wheat Head Armyworm. True or False: A Tale from the Pacific Northwest

item Rondon, Silvia - Oregon State University
item Corp, Mary - Oregon State University
item Roberts, Diana - Washington State University
item Pike, Keith - Washington State University
item Landolt, Peter
item Keys, Dustin - Oregon State University

Submitted to: Oregon State University Extension Publications
Publication Type: Experiment Station
Publication Acceptance Date: 12/21/2009
Publication Date: 12/31/2009
Citation: Rondon, S., Corp, M.K., Roberts, D., Pike, K.S., Landolt, P.J., Keys, D. 2009. Wheat Head Armyworm. True or False: A Tale from the Pacific Northwest. Oregon State University Extension Publications. OSU EM 9000-E Dec. 2009. 4 pp.

Interpretive Summary: Cutworms, armyworms, and loopers are caterpillars that damage numerous crops when they feed on foliage, fruits, stems, and roots. Growers need better information on which species should be of concern on different crops so that they can be detected and monitored for effective pest management. Researchers at the USDA, ARS Yakima Agricultural Research Laboratory, Wapato, WA, in collaboration with scientists at Oregon State University and Washington State University, are determining the identity of caterpillars that cause significant damage to crops in the Pacific Northwest and are developing methods for monitoring there abundance. Trapping experiments showed that the moth Faronta terrapictalis was abundant where damage to wheat had been blamed on the wheat head armyworm, Faronta diffusa.. Information on the armyworm and the related species F. terrapictalis are summarized for presentation to growers and crop consultants. This new information clarifies the identity of the insect causing damage to the crop and provides growers and consultants with the methods for monitoring both species.

Technical Abstract: In 2007 and 2008 large numbers of caterpillars were found that were tentatively identified as wheathead armyworm moths, Faronta diffusa. In 2009, traps baited with a sex attractant, traps with a feeding attractant, and light traps were used to determine the relative abundance and distribution of this pest, which was not known to be in the state of Washington. Although a small number of wheat head armyworm moths were trapped, a closely related moth, Faronta terrapictalis, was captured in much larger numbers (ca 100X), only in sex attractant traps. During the 2009 field season, no larvae were seen. At this time then, it is not certain if previous infestations and damage were due to diffusa or to terrapictalis.