- Agronomic: sunflower
- Vegetables: peppers, sweet corn
- Crop Production: intercropping
- Education and Training: on-farm/ranch research
- Pest Management: biorational pesticides, row covers (for pests), trap crops
- Production Systems: organic agriculture
The invasive brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), has become a significant pest of vegetables in Virginia. Field experiments were conducted on two Virginia farms in 2012 and 2013 to determine if BMSB populations could be maintained below economically-damaging levels in bell peppers through implementation of a trap crop. In 2012, there were no differences in BMSB densities on peppers bordered by a row of trap plants of either sunflower or corn compared to control peppers with no trap border. In 2013, higher numbers of BMSB were observed on control peppers compared to either of the trap crop treatments. There was no effect of trap crop treatment on stink bug damage to pepper fruit in either year. Stink bug damage averaged 30-40% and 20-25% in 2012 and 2013, respectively, regardless of treatment. Also in both years, BMSB egg masses were collected from fields and assessed for parasitism levels from native stink bug egg parasitoids in southwest Virginia to determine the potential biological control impact on this invasive pest. BMSB egg parasitism levels averaged from 6 to 17% across three years of sampling BMSB eggs in trees and on agricultural crops. Additional research studies were conducted to evaluate the efficacy of pyrethroid-incorporated polyethylene mosquito netting as a control tool for protecting vegetables against BMSB and other agricultural pests. Fresh netting as well as netting that had aged in the field for one year were shown to be toxic to BMSB, killing over 70% of nymphs and adults after constant exposure to the screen for 2 hrs. Field efficacy trials showed that the treated screening provided significant control of flea beetles on collards and eggplant and cucumber beetles on melons better than untreated polyethylene screening. Further research should be done on the potential of long-lasting pyrethroid-treated polyethylene screen as a row cover to protect high value commodities from certain insect pests.
The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), a native of eastern Asia was accidently introduced into Pennsylvania in the late 1990’s (Hamilton 2009), and has since spread across much of the continental United States. Isolated populations also exist in Switzerland, France and Canada. Current research and observations in the mid-Atlantic states have shown that BMSB has tremendous potential to reduce yields in numerous agricultural commodities.
Halyomorpha halys can cause significant injury to a wide range of vegetable crops when bugs insert their feeding stylets into plant fruiting bodies, which are often the marketable portion of the crop. In corn (Zea mays), BMSB stylets are inserted through the husk and pierce the tender kernels, which may cause them to become aborted, collapsed, or discolored. Feeding injury to beans (Phaseolus spp.) may result in scarred, faded out sunken areas, and deformed pods. Injury to fleshy fruit, like tomatoes (Solanum lycopersicum L.), and peppers (Capsicum annuum L.), will produce white spongy areas on the skin and tissue damage internally where the feeding stylets were inserted into the fruit. Okra (Abelmoschus esculentus Moench) is also fed upon by this pest resulting in deformed seed pods. Along with reduced quality of the marketable produce, feeding injury to these vegetable may reduce fruit set and subsequent yield by causing adortion of flower buds and young fruiting bodies. In addition to direct damage, the feeding stylets of BMSB also have been shown to transmit pathogenic microorganisms such as bacteria and yeast such as Eremothecium coryli, which can cause fruit rot. Overall losses exceeding 50% due to stink bug damage are common under heavy infestations. Among vegetables, sweet corn, okra and pepper appear to be highly preferred host plants in terms of adult colonization and reproduction. Eggplant (Solanum melongena L.) and green bean are also suitable host plants for egg laying and nymphal development. Tomato appears to be less suitable for BMSB reproduction, but can suffer severe fruit damage, particularly in late August. Other vegetables such as asparagus and those in the cucurbit or brassica groups also may be fed upon by BMSB, but to a lesser degree and dependent upon their proximity to more preferred vegetables.
With the exception of early maturing sweet corn, which may encounter BMSB attack as early as late June, the majority of vegetable crops are attacked from late July to October in the mid-Atlantic U.S (Kuhar et al. 2012). In mixed vegetable plantings, or small farms with diverse crops, there is often significant inter-plot movement of BMSB adults and nymphs over the growing season dependent upon the relative attractiveness of each crop. Stink bug feeding injury on fruit may result in a white spongy area on the surface of the fruit and catfacing damage, which render the fruit unmarketable for fresh market use.
Frequent applications of broad-spectrum insecticides have increased in an attempt to control BMSB. Although several registered insecticides have been shown to be efficacious at controlling BMSB, all of these products also kill beneficial insects, and are therefore, disruptive to IPM systems and not sustainable. This pest poses an an even greater challenge to organic systems, where no real effective control strategies have been identified. Currently available organic pesticides are generally not effective at reducing stink bug populations in field situations (Kamminga et al. 2009). Compared to native stink bug populations, BMSB can occur at unusually high numbers in agricultural systems. These tremendous numbers may be possible in part because there are few natural enemies of BMSB in North America. For instance, about 50% of native stink bug eggs are parasitized (Koppel et al. 2009); while recent reports by Dr. Kim Hoelmer, of the USDA-ARS, indicate that egg parasitism of BMSB may only be around 5%. Additionally, Dr. Hoelmer states that a common obligate parasitoid of native stink bugs, tachinids, are not able to complete development in BMSB (Holtz and Kamminga 2010).
Hamilton, G. C. 2009. Brown marmorated stink bug. Amercan Entomol 55:19-20.
Holtz, T, and K. Kamminga. 2010. Qualitative analysis of the pest risk potential of the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), in the United States. USDA APHIS Plant Epidemiology and Risk Analysis Laboratory CPHST PPQ.
Kamminga, K.L., D.A. Herbert, T.P. Kuhar, S. Malone, and H. Doughty. 2009. Toxicity, feeding preference, and repellency associated with selected organic insecticides against Acrosternum hilare and Euschistus servus (Hemiptera: Pentatomidae). J. Econ. Entomol. 102: 1915-1921.
Koppel, A.L., D.A. Herbert, Jr., T.P. Kuhar, and K. Kamminga. 2009. Survey of stink bug (Hemiptera: Pentatomidae) egg parasitoids in wheat, soybean and vegetable crops in Southeast Virginia. Environ. Entomol. 38: 375-379.
Current control options for BMSB include older broad-spectrum insecticides such as organophosphate, carbamates and pyrethroids that are disruptive and hazardous to the environment. We plan to test cultural, biological, and mechanical control methods that may offer alternative methods of control for BMSB. These methods are part of IPM programs and safer for humans and non-target species.
Stink bugs typically move into an agricultural field from nearby wild hosts; therefore, causing greater injury and crop loss along the perimeter of a field. A potential management method to decrease crop loss is planting a trap crop. Trap crops have been successfully used to reduce stink bugs in soybean by planting more attractive soybeans along the field perimeter (Smith et al. 2009). The stink bugs prefer the early maturing bean pods confining them to an easily treatable area for the grower. Trap crop implementation may reduce chemical sprays since treatment would only be applied to the trap crop instead of the entire field. The reduction in insecticide application saves money for the grower, is safer for the environment, and serves as a refuge for natural enemies.
Our preliminary data from 2010 indicate that BMSB is strongly attracted to sweet corn and sunflower when present on a farm. Thus, sunflower or sweet corn could potentially serve as a trap crop for bell pepper and other high value crops. A successful trap crop may reduce stink bugs in the primary crop and consequently reduce feeding damage. Furthermore, the use of a trap crop offers a habitat for beneficial insects to thrive. Adult egg parasitoids feed on flower nectar. Thus, a trap crop such as sunflower will not only be a refuge, but also a potential food source for beneficial insects.
A mechanical control strategy that has received very little attention in an agricultural system is a physical barrier to prevent insects from feeding on high value plants. A screen barrier such as mosquito netting could eliminate the need for insecticide application. Placed over crop plants, it will protect the high value vegetables from stink bugs as well as other flying pests.
Smith, J.F., R.G. Luttrell, J.K. Greene, and C. Tingle. 2009. Early-season soybean as a trap crop for stink bugs (Heteroptera: Pentatomidae) in Arkansas changing system of soybean production. Environ. Entomol. 38: 450-458.
Objective 1: Evaluate the potential of a trap crop of sweet corn and sunflower trap crops to reduce the numbers of BMSB in the primary crop, bell peppers.
Objective 2. Evaluate if a trap cropping system increases egg parasitisim of the BMSB.
Objective 3. Evaluating the potential of new technology to reduce stink bug damage on high value vegetables.