Assessment of the biological control potential of common carabid beetle species for autumn and winter active pests (Gastropoda, Lepidoptera, Diptera: Tipulidae) in annual ryegrass in Western Oregon

Authors: REICH, INGA - Oregon State University; JESSIE, CASI - Oregon State University; AHN, SEUNG-JOON - Mississippi State University; Choi, Man-Yeon; WILLIAMS, CHRISTOPHER - John Moores University; GORMALLY, MIKE - National University Of Ireland; MCDONNELL, RORY - Oregon State University

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2020
Publication Date: 10/22/2020
Citation: Reich, I., Jessie, C., Ahn, S., Choi, M.Y., Williams, C., Gormally, M., McDonnell, R. 2020. Assessment of the biological control potential of common carabid beetle species for autumn and winter active pests (Gastropoda, Lepidoptera, Diptera: Tipulidae) in annual ryegrass in Western Oregon. Insects. 11(11). Article 722. https://doi.org/10.3390/insects11110722.
DOI: https://doi.org/10.3390/insects11110722

Interpretive Summary: Slugs are a global problem in agriculture. In Oregon, slugs, including both native and invasive species, attack a broad spectrum of crops and agricultural industries. Slugs affect a wide range of cropping systems, including seed production, field crops, row crops, Christmas tree farms, and horticultural nurseries. The infestations and resulting damage/problems associated with slugs are increasing. In new fields, the cost of bait applications, direct loss of plants, and the cost of replanting is estimated to cost the seed industry > $50 million. The current control methods with chemical pesticides should be reduced or replaced with biologically-based environmentally friendly alternatives. Recently, we studied a multi-step approach to assess, for the first time, the biological control potential of carabid beetles for pest slugs in annual ryegrass in Western Oregon. Our research results provide information on best management practices for conservation biological control.

Technical Abstract: Annual ryegrass, a major cash crop grown for seed in Oregon, is particularly susceptible to damage from autumn and winter active pests such as slugs, caterpillars, and crane fly larvae. Little is known about carabid beetles that can act as conservation biological control agents of these crop pests. Ten ryegrass fields were sampled from March 2018 to June 2019 using pitfall and refuge traps. Four beetle species total were identified as the common species in the fields. DNA detection of beetle gut contents indicated the presence of slug, lepidopteran, and crane fly DNA in 9.3%, 7.5%, and 6.1% of 282 tested specimens, respectively. Feeding incidences on slugs were highest in spring (12.9%), while 15.3% of autumn collected the beetle were found to have consumed caterpillars at a time when annual ryegrass is most susceptible to damage by pests. None of the four common carabid species was affected by disk tilling, and only the distribution of the beetle was significantly associated with a vegetation field margin.