Submitted to: Phytoparasitica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2007
Publication Date: September 10, 2007
Citation: Lacey, L.A., Unruh, T.R., Simkins, H., Thomsen Archer, K.L. 2007. Gut bacteria of the Pacific coast wireworm, Limonius canus, inferred from 16s rDNA sequences and their implications for control. Phytoparasitica. 35:479-489. Interpretive Summary: The Pacific coast wireworm is found in irrigated crops in Western North America where it is a pest of several grains and vegetables. In the Pacific Northwest, it is a serious pest of potato and damages tubers by tunneling and feeding. Scientists at the USDA-ARS Yakima Agricultural Research Laboratory are investigating alternatives to chemical pesticides for control of the wireworm. They have found several bacteria in the gut of wireworm larvae in Oregon and Washington potato fields that might be modified to produce conditions that are lethal to larvae or reduce their survival. Future research will be focused on modification of some of these bacteria with toxins or other products that are detrimental to the larvae.
Technical Abstract: A multitude of bacteria have been isolated from the guts of several insect species. Some of these have been modified to interfere with the development of the host insect or interfere with the development and transmission of plant and animal pathogens transmitted by the host insect. A survey of the gut flora of the Pacific Coast wireworm, Limonius canus, a serious pest of potato, was conducted on insects collected from two sites in Oregon and Washington. Four sampling dates at each location yielded 86 isolates comprising a rich diversity of species including spore formers, non-spore formers and aerobic and facultatively anaerobic species. Twenty one of the isolates were identified to species based on rDNA sequence; these isolates comprised 10 distinct species. An additional 34 isolates were identified to genus from the sequence data; only 6 isolates could not be resolved below family from the sequence comparisons. Twenty-seven additional isolates were identified to species (11), genus (15) or family (1) based on side-by-side morphological comparisons with isolates identified from rDNA sequence. The most common and frequently isolated bacterium at both sites was Bacillus megaterium. This species and others that were isolated at one or both sites will be candidates for genetic modification that could provide options for control of L. canus.