Location: Southeast Watershed Research
2017 Annual Report
Objectives
1. Determine biological, ecological, and structural mechanisms driving stink bug population dynamics in landscapes composed of agricultural (e.g., corn, peanut, cotton, and soybean) and non-agricultural habitats to design management strategies for stink bugs in the Southeastern Region of the United States.
1.A. Determine the seasonal occurrence and biology of stink bugs in non-crop habitats in agricultural landscapes.
1.B. Determine stink bug dispersal from non-crop hosts into cotton and the impact on cotton in terms of boll injury.
1.C. Investigate the potential for host-associated differentiation (HAD) in parasitoids of stink bug adult, nymph and egg stages.
1.D. Deploy use of Long-term Agricultural Research (LTAR) sites and eco-informatics to establish causal relationships between environmental and geospatial data, management strategies, and pest control success in vegetable crops such as cucurbits, fruiting vegetables, onions, cabbage, leafy greens and sweet corn.
2. Develop and test biologically-based management strategies, including augmentative releases of parasitoids, trapping insect pests with pheromone traps, elimination of non-crop sources of stink bugs, biopesticides, and multifunctional trap cropping systems, to monitor and/or control native and naturalized stink bugs and the invasive kudzu bug and the brown marmorated stink bug in the Southeastern Region of the United States.
2.A. Determine the efficacy of augmentative releases of kudzu bug parasitoids in reducing kudzu bug populations.
2.B. Monitor populations of the newly invasive brown marmorated stink bug using pheromone-baited stink bug traps.
2.C. Determine the effect of selected biopesticides on the kudzu bug in soybean.
2.D. Examine the utility of eliminating non-crop host plants of stink bugs along field edges for reduction of stink bug dispersal into cotton.
2.E. Evaluate the effectiveness of using a soybean trap cropping system to manage stink bugs attacking cotton.
Approach
Collect data on the seasonal occurrence, development and feeding and mating behavior of stink bugs in known and potential non-crop habitats surrounding row crops in 10-12 agricultural landscapes. Conduct a study of stink bug dispersal from known non-crop hosts into cotton and their impact on cotton boll injury in 6-8 agricultural landscapes. Conduct a study on the presence of host-associated differentiation in parasitoids of stink bug adults, nymphs and eggs collected in cotton and soybean fields and from nearby known non-crop host plants. Conduct a study on the effects of augmentative releases of an exotic kudzu bug egg parasitoid on kudzu bug density in 10 kudzu patches in North and South Georgia and nearby soybean fields. Monitor populations of the newly invasive brown marmorated stink bug north of the Coastal Plain in Georgia using pyramid stink bug traps baited with lures and map its distribution and spread in Georgia. Conduct studies in experimental plots on selected biopesticide effects on kudzu bug populations in soybean. Conduct a study on the elimination of known non-crop host plants of stink bugs along 6 cotton field edges on stink bug dispersal into the cotton field. Conduct a study in a grower’s peanut-cotton farmscape on the effect of a soybean trap cropping system on the density of stink bugs attacking cotton.
Progress Report
The second year of a study determining the genetic structure and parasitism rates of stink bug parasitoids on crop and non-crop host plants is underway (Objective 1.C), and several specimens have been collected to date with further collections and molecular analyses ongoing. A census of kudzu bug adults, nymphs and eggs in kudzu in Georgia indicating the steady population decline over four years has been completed and the results have been published (Objective 2.A). A petition to import and release an exotic egg parasitoid from Japan where all non-target tests have been completed and that is likely more adapted to larger areas of the southeastern United States than the current adventive parasitoid has also been completed and submitted to Animal and Plant Health Inspection Service (APHIS) in the event that there is a resurgence of the kudzu populations (Objective 2.A). The second year of a study to assess seasonal occurrence and biology of stink bugs in non-crop hosts is in progress (Objective 1.A). The first year of a study on dispersal of stink bugs from black cherry and mimosa is ongoing (Objective 1.B). Brown marmorated stink bugs are being monitored throughout the state of Georgia using pheromone-baited traps.
Accomplishments
1. Potential for production of perennial biofuel feedstocks in conservation buffers. Bioenergy cropping in marginal areas of the southeastern USA presents a major opportunity to improve ecosystem services and has the potential to expand current commodities for production in the region while reducing competition between biofeedstocks and traditional agricultural commodities. ARS and University of Georgia researchers in Tifton, Georgia, have established twenty conservation buffers on marginal land that include napier grass for biofuel and native wildflower plots for pollinators and arthropod predators of agricultural pest species. Floral visitation by pollinators and natural enemies occurred more frequently in the flower than in the weed plots. Herbivore floral visitation was less frequent than pollinators and natural enemies in all of the plots (both flower and weed plots). Buffer location context (adjacent to woodland or agriculture) and irrigation had no effect on pollinator, natural enemy and herbivore floral visitation. Pollinators were also more abundant early in the season (mid-June) in all three of the native wildflower commercial mixes. Several crops in the region also flower early in the season and rely on pollinators, suggesting that maintaining pollinators near these crops may be very important to crop production. The site specific yields of napier grass were high and in typical yield ranges found for this species in the southeastern USA. Napier grass yields appeared to be influenced more by soil properties than buffer location and irrigation; the highest yields were obtained in the plot with the highest level of calcium and phosphorous, and buffer location and irrigation had no effect on yield. This marginal land model shows a synergistic approach towards ecological intensification in agriculture which would provide needed services to the landscapes in the region and the potential for economic returns to the growers.
2. Stink bugs are economic pests of cotton. A study was conducted to determine if elderberry in woodland habitats serves as a source of stink bugs into cotton alongside these habitats and to examine parasitization of naturally-occurring stink bug eggs on this non-crop host. Four species of stink bugs fed and developed into adults on elderberry, and seven species of parasites attacked stink bug eggs. As elderberry died and cotton bolls became available, large nymphs and adults dispersed from elderberry into cotton based on the fact that stink bugs which had been marked in elderberry were recaptured in cotton. Over the 2-yr study, economic threshold was reached for four of the seven cotton field plots. Thus, dispersal of stink bugs from elderberry into cotton can result in economic damage to this crop. Elimination of elderberry in woodland habitats adjacent to cotton may be a viable biologically-based management tactic for control of stink bug populations in this crop.
Review Publications
Tillman, P.G., Cottrell, T.E. 2016. Density and egg parasitism of stink bugs (Hemiptera: Pentatomidae) in elderberry and dispersal into crops. Journal of Insect Science. 16:108. doi:10.1093/jisesa/iew091.
Gardner, W., Olson, D.M. 2016. Population census of Megacopta cribraria (Hemiptera: Plataspidae) in kudzu in Georgia, USA, 2013-2016. Journal of Entomological Science. 51(4):325-328. https://doi.org/10.18474/JES16-29.1.
Hoshino, K., Adati, T., Olson, D.M., Takasu, K. 2017. Seasonal occurrence and interspecific interactions of egg parasitoids of Megacopta cribraria (Heteroptera: Plataspidae) in Japan. Environmental Entomology. 46(3):487-493. https://doi.org/10.1093/ee/nvx060.
Tillman, P.G. 2015. First record of Sesbania punicea (Fabales: Fabaceae) as a host plant for Chinavia hilaris (Hemiptera: Pentatomidae). Florida Entomologist. 98:989-990.
Tillman, P.G., Cottrell, T.E. 2016. Stink bugs (Hemiptera: Pentatomidae) in pheromone-baited traps near crop field edges in Georgia, USA. Florida Entomologist. 99:363-370.
Tillman, P.G. 2016. Diversity of stink bug (Hemiptera: Pentatomidae) egg parasitoids in woodland and crop habitats in southwest Georgia, USA. Florida Entomologist. 99:286-291.
Tillman, P.G., Cottrell, T.E. 2017. Use of pheromones for monitoring phytophagous stink bug (Hemiptera: Pentatomidae) populations. In: Cokl, A., Borges, M., editors. Stinkbugs: Biorational Control Based on Communication Processes. Boca Raton, FL:CRC Press. p. 210-225.
Ni, X., Cottrell, T.E., Toews, M.D., Tillman, P.G., Buntin, G.D. 2016. Diurnal activities of the brown stink bug (Hemiptera: Pentatomidae) in and near tasseling corn fields. Journal of Entomological Science. 51(3):226-337.
Tillman, P.G., Cottrell, T.E. 2016. Attraction of stink bug (Hemiptera: Pentatomidae) nymphs to Euschistus aggregation pheromone in the field. Florida Entomologist. 99:678-682.
