Survey of Stink Bug (Hemiptera: Pentatomidae) Egg Parasitoids in Wheat, Soybean, and Vegetable Crops in Southeast Virginia

Abstract

Stink bugs (Hemiptera: Pentatomidae) cause significant damage to many different crops and horticultural commodities in Virginia. However, little is known about the species diversity or impact of stink bug egg parasitoids in the state. A survey was conducted in 2005 and 2006 (May through September) in wheat (Triticum aestivum L.), soybean (Glycine max L.), and several vegetable crops by collecting natural egg masses of various stink bug species and by monitoring sentinel egg masses. A total of 570 Euschistus servus (Say) eggs in 26 egg masses, 11,197 Murgantia histrionica (Hahn) eggs in 939 egg masses, 15 Podisus maculiventris (Say) eggs in 2 egg masses, and 546 Acrosternum hilare (Say) eggs in 18 egg masses were field collected and returned to the laboratory, where emerging parasitoids were identified to species. In addition, 2,512 laboratory-reared E. servus eggs and 230 P. maculiventris eggs were placed as sentinels into crop fields and collected after 7 d, and parasitoid or stink bug emergence was recorded. Four species of hymenopteran parasitoids in the family Scelionidae were recovered from stink bug eggs: Telenomus podisi Ashmead, Trissolcus basalis Wollaston, Trissolcus edessae Fouts, and Trissolcus euschisti Ashmead. In addition, one parasitoid in the family Mymaridae (Hymenoptera) was recovered. Parasitism rates were highest in E. servus with 89.7 and 49.2% of egg masses and individual eggs parasitized, respectively. The predominant parasitoid species was T. podisi.

A modified DNA barcode approach to define trophic interactions between native and exotic pentatomids and their parasitoids

“…Koppel et al. () also found the highest parasitism in E. servus (90%) and documented 20 and 100% parasitism in egg masses of Po. maculiventris and C. hilaris , respectively, in a variety of crops.…”

“…However, this discrepancy between parasitism at the egg mass versus individual egg level is also observed in reared samples of native pentatomid egg masses in other North American studies and therefore may be associated with parasitoid reproductive biology and/or patch exploitation behaviour, rather than a methodological impediment. Koppel, Herbert, Kuhar, and Kamminga () found 67% total parasitism in pentatomid egg masses, but only 22% parasitism at the individual egg level. Although this could be due to parasitoid mortality in rearing, the values are consistent with what we found using molecular tools and suggest that under field conditions, egg masses may be partially exploited by a parasitoid (Laumann et al., , ).…”

Strain Specific Differences in Intraspecific Competition inAedes albopictus(Diptera: Culicidae)

“…Survivorship data were analyzed with a regression based on binomial distribution with densities as continuous variables and strain (Þeld and lab) as discrete variables and the Pearsons 2 statistic (Pscale under PROC GENMOD) was used to account for over-dispersion (SAS Institute 2004, Fletcher 2012, Koppel et al 2009). Because of low survivorship in the presence of insecticide, individuals from the treatment were excluded for subsequent analysis.…”

Harlequin Bug Biology and Pest Management in Brassicaceous Crops

“…At least three species of native hymenopteran wasps parasitize the eggs of harlequin bug including Ooencyrtus johnsoni Howard (Encyrtidae), Trissolcus murgantiae Ashmead [T. brochymenae Ashmead] (Scelionidae), and Telenomus podisi Ashmead (Scelionidae) (White and Brannon 1933, Huffaker 1941, Koppel et al 2009). Because of its success in the southern United States (Huffaker 1941), T. murgantiae was introduced into California as a biological control agent and later recovered from harlequin bug eggs (DeBach 1942).…”

“…Surveys evaluating egg parasitism rates range from 8 to 50% of field collected eggs with higher rates of parasitism occurring in years of heavy harlequin bug infestation (Huffaker 1941, Ludwig andKok 1998). In the 1990s, Ludwig and Kok (1998) primarily recovered T. murgantiae and O. johnsoni from harlequin bug collected in Virginia, but more recently Koppel et al (2009) found only T. podisi in Virginia, with 63.5% of harlequin bug egg masses and 12.9% of the total eggs parasitized. As with a related species Trissolcus basalis Wollaston, T. murgantiae and T. podisi may use chemical volatiles emitted from female harlequin bugs to find the host eggs (Salerno et al 2006(Salerno et al , 2009.…”