Location: Systematic Entomology LaboratoryTitle: Predation and Parasitism Rates on Sentinel and Naturally Occurring Egg Masses of the Squash Bug (Hemiptera: Coreidae) in Maryland Author
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2015
Publication Date: 1/11/2016
Citation: Cornelius, M.L., Buffington, M.L., Talamas, E.J., Gates, M.W. 2016. Predation and Parasitism Rates on Sentinel and Naturally Occurring Egg Masses of the Squash Bug (Hemiptera: Coreidae) in Maryland. Environmental Entomology. DOI: http://dx.doi.org/10.1093/ee/nvv228 367-375.. Interpretive Summary: Parasitic wasps provide natural control of insect pests in a variety of agricultural and horticultural ecosystems, saving hundreds of millions of dollars annually. We report here on wasps that provide control of squash bugs by attacking their eggs. These wasps can help growers of squash (and relatives) reduce chemicals used in control of these pests, reducing harmful effects on the environment caused by chemicals. This work will be used by biocontrol specialists, scientists, and extension agents.
Technical Abstract: Seasonal changes in egg predation and parasitism rates on sentinel and naturally occurring (wild) egg masses of the squash bug, Anasa tristis (DeGeer), were evaluated in squash fields in Maryland from June through September in 2013 and 2014. Rates of egg predation and parasitism were significantly higher on wild egg masses than on sentinel egg masses. Squash bug nymph eclosion was significantly higher on sentinel egg masses than on wild egg masses. Between the first week of July and the first week of September, squash bug nymphs successfully completed development from less than 25% of wild eggs compared with 46.2% of sentinel eggs and parasitoids emerged from 55.7% of wild eggs compared with only 21.8% of sentinel eggs. Sentinel egg masses significantly underestimated the rate of egg parasitism. The egg parasitoid, Gryon pennsylvanicum (Ashmead), was responsible for over 99% of parasitism of squash bug eggs. These results demonstrate that G. pennsylvanicum was able to efficiently track naturally occurring squash bug eggs throughout the season and that it is (?) an effective biological control agent of the squash bug.