Spatial Distribution of Megacopta cribraria (Hemiptera: Plataspidae) Egg Masses and Parasitism By Paratelenomus saccharalis (Hymenoptera: Platygastridae) in Soybean

Feeding by an invasive stink bug, Megacopta cribraria (F.), can reduce soybean yields in the southeastern US by as much as 60% in untreated fields. The egg parasitoid Paratelenomus saccharalis was discovered attacking M. cribraria egg masses in kudzu and soybean from several southeastern states in 2013.  Megacopta cribraria egg masses from two commercial soybean fields in South Georgia were sampled at a density of one sample per 0.6 ha to determine the within-field distribution of egg masses and incidence of parasitism over time.  All egg masses within a square meter at each sample site were collected, enumerated, and assessed for parasitism. Effect of week and distance from edge of the field were modeled and Spatial Analysis of Distance Indices (SADIE) were calculated.  M. cribraria egg masses were spatially clustered and associated with field edges. Parasitism by P. saccharalis reached its maximum, 20 and 37 % respectively, during the month of August.  Parasitism of egg masses was clustered in space but not through time.