Submitted to: Northwest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 15, 2002
Publication Date: March 1, 2003
Citation: Landolt, P.J., Smithhisler, C.L. 2003. Characterization of the floral odor of Oregon grape: possible feeding attractants for moths. Northwest Science. 77:81-86 Interpretive Summary: New methods and approaches are needed to control insect pests of potato and other vegetable crops, with reduced use of pesticides that are harmful to human health or the environment. Researchers at the USDA-ARS laboratory in Wapato, Washington are discovering new attractants and are improving existing attractants for insect pests of potato as part of a program to develop pest monitoring methods and bait stations. Larvae of the alfalfa looper presently require applications of pesticides to prevent damage to potato and other vegetable crops in the western U.S. It was found that moths of the alfalfa looper feed at flowers of a native shrub, Oregon grape. Analyses of chemical emitted by Oregon grape flowers provided the identification of 8 chemicals that may be attractants for this and other insect species. Two of these chemicals, phenylacetaldehyde and benzaldehyde, are attractants for some species of looper moths, including the alfalfa looper. These results provide possible new chemical attractants and attractant blends for use in the development of bait station applications to replace pesticide applications.
Technical Abstract: It was hypothesized that flowers of Oregon grape, Berberis aquifolium Prursch., might release chemicals attractive to moths. Studies were conducted to determine what moths visit flowers of Oregon grape and to characterize the odor chemistry of those flowers in search of possible moth feeding attractants. Moths, bees, wasps, and flies were captured in traps placed over blooms of Oregon grape, during March, April, and May 2001. Moths captured were predominantly the alfalfa looper Autographa californica (Speyer) (Lepidoptera: Noctuidae) (43%), and Zophodia grossulariella (Hubner) (Lepidoptera: Pyralidae) (26%) with smaller numbers of 11 other Noctuidae and 3 Geometridae species. Volatile collections made from blooms of Oregon grape shrubs revealed the consistent present of 8 compounds. These were ß-pinene, alpha-pinene, sabinene, E-ß-ocimene, ß-myrcene, limonene, benzaldehyde, and phenylacetaldehyde. Greatest amounts released by flowers were of phenylacetaldehyde (124.5 + 40.8 ng/flower/hour), and racemic limonene (43.9 + 7.0 ng/flower/hour). Phenylacetaldehyde and benzaldehyde are known attractants for some moths, including the alfalfa looper. Odorants produced by flowers of Oregon grape shrubs likely mediate orientation of particular moth visitors to those flowers.