Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2014
Publication Date: 5/1/2014
Citation: Greenstone, M.H., Tillman, P.G., Hu, J.S. 2014. Predation of the newly invasive pest Megacopta cribraria (F.) (Hemiptera: Plataspidae) in soybean habitats adjacent to cotton by a complex of predators. Journal of Economic Entomology. 107:947-954. Interpretive Summary: The kudzu bug is a newly-invasive insect feeding primarily on kudzu, but it also is a pest in soybean in the southeastern United States, where it constitutes a serious threat to crop production. Our main objective in this research was to identify predators of the kudzu bug by detecting DNA of this bug in the guts of predatory insects and spiders collected from soybean and adjacent cotton. We also wished to determine whether these predators included other pest insects in the two crops in their diets. Eight native arthropod predators, including two big-eyed bugs, a pirate bug, a predatory stink bug, the leafhopper assassin bug, a lady beetle, and two species of lynx spider, contained DNA remains of the kudzu bug in their guts; one exotic predator, the red imported fire ant, also tested positive for kudzu bug DNA. We found two species of plant-feeding stink bugs exclusively on soybean, and another only on cotton. Many of the collected predators had DNA of both the kudzu bug and one or more of these plant-feeding stinkbugs in their guts, indicating that these predators likely migrate between cotton and soybean. Therefore, establishing cotton “refuges” for predators adjacent to soybean could enhance their effectiveness as biological control agents against kudzu bug. These results are of interest to soybean producers, pest management consultants, and scientists.
Technical Abstract: The kudzu bug, Megacopta cribraria (F.) (Hemiptera: Plataspidae), is a newly-invasive exotic insect found primarily on kudzu, but also on soybean, in the southeastern United States. We used molecular gut-content analysis to document predation on this pest by insects and spiders in soybean; and to detect remains of crop-specific alternative prey in predators’ guts as markers of predator migration between soybean and adjacent cotton. Megacopta cribraria was found only on soybean. Eight native generalist predators in both crops screened positive by specific PCR for DNA of the pest: Geocoris punctipes (Say), Geocoris uliginosus (Say), Orius insidiosus (Say), Podisus maculiventris (Say), Hippodamia convergens Guérin-Méneville, Zelus renardii (Kolenati), Oxyopes salticus Hentz, and Peucetia viridans (Hentz); a ninth predator, the exotic Solenopsis invicta Buren, also screened positive for M. cribraria DNA. Two plant-feeding pentatomid species, Piezodorus guildinii (Westwood) and Thyanta custator (F.), were found exclusively on soybean, and another, Euschistus tristigmus (Say), was specific to cotton. Predation on a combination of M. cribraria and one or more of the three stink bug species by significant numbers of predators in soybean and adjacent cotton revealed that these predators likely dispersed between the two crops. This suggests that establishment of refugia for these predators might enhance their effectiveness against M. cribraria on soybean. This is the first report of predation in the field on this exotic pest in North America.