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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Invasive Insect Biocontrol & Behavior Laboratory » Research » Publications at this Location » Publication #319555
Title: Impact of the egg parasitoid, gryon pennsylvanicum (Hymenoptera: Scelionidae), on sentinel and wild egg masses of the squash bug (Hemiptera: Coreidae) in Maryland

Author
item Cornelius, Mary
item Buffington, Matthew
item Talamas, Elijah
item Gates, Michael

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2015
Publication Date: 1/11/2016
Publication URL: http://handle.nal.usda.gov/10113/62264
Citation: Cornelius, M.L., Buffington, M.L., Talamas, E.J., Gates, M.W. 2016. Parasitism and predation rates on sentinel and naturally occurring egg masses of the squash bug (Hemiptera: Coreidae) in Maryland. Environmental Entomology. 45(2) 367-375.

Interpretive Summary: Seasonal changes in egg predation and parasitism rates on sentinel and naturally occurring (wild) egg masses of the squash bug 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 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, was responsible for over 99% of parasitism of squash bug eggs. With the exception of the first two weeks of July, parasitoids were able to emerge from at least one egg in over 60% of wild egg masses collected. 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. This research provides evidence that biological control of squash bugs by the egg parasitoid, G. pennsylvanicum, could potentially be a successful pest control management strategy for farmers and urban gardeners.

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 of both survey years, 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. With the exception of the first two weeks of July, parasitoids were able to emerge from at least one egg in over 60% of wild egg masses collected. 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.