By John P. Roche
The redbanded stink bug (Piezodorus guildinii) is an invasive species in the southern United States that feeds on the sap from seeds, pods, flowers, stems, and leaves of soybean plants. It causes considerable economic losses in soybean growing regions. In June, a group of researchers at the U.S. Department of Agriculture (USDA) published an in-depth review in the Journal of Integrated Pest Management (JIPM) that details the biology, ecology, and integrated pest management strategies for controlling redbanded stink bugs.
Piezodorus guildinii is a member of the family Pentatomidae within the order Hemiptera—the true bugs. The Pentatomidae includes other stink bug pest species, including the southern green stink bug (Nezara viridula), the green stink bug (Chinavia hilaris), and the brown stink bug (Euschistus servus), all of which are also pests of soybeans.
In addition to the southern U.S., the redbanded stink bug’s range includes parts of the Caribbean, Mexico, Central America, and South America. Individual redbanded stink bugs progress from egg to adult in an average of 39 days, going through five instar nymph stages. Feeding begins in the second instar stage. The species produces multiple generations per year. For example, in Louisiana, redbanded stink bugs produce four to eight generations annually.
Plants preferred by the redbanded stink bug include winter pea, hairy vetch, common bean, sunflower, and clover species. In the early summer, it feeds on its preferred host plants. When these preferred hosts die off later in the summer, it switches to feeding on soybean and other legumes.
Redbanded stink bugs were first discovered in the Caribbean in the early 20th century and first seen in the U.S. in the 1960s. They have undergone a dramatic increase in the U.S. since then. Redbanded stink bugs reduce yield, reduce seed weight, and interfere with development of soybean plants, costing U.S. agriculture over $25 million per year. In addition, when they pierce soybean plants to suck out sap, they can introduce plant pathogens to crop plants.
“Red banded stink bugs are polyphagous in nature with many cultivated and wild host plants,” says Justin George, PhD., a research entomologist at the USDA Agricultural Research Service’s Southern Insect Management Research Unit and second author on the JIPM article. The lead author is Olabimpe Okosun, Ph.D., at the USDA-ARS Pollinator Health in Southern Crop Ecosystems Research Unit.
“They are a major concern to soybean and other legume crops,” Georg says. “Studies have reported that redbanded stink bug infestation could lead to more crop loss per capita than other stink bug species.”
Control approaches for redbanded stink bug include chemical control, cultural and physical control, and biological control using parasitoids and other species. Chemical control using synthetic insecticides has been the primary method, but many redbanded stink bug populations have developed resistance to numerous insecticides—more resistance than other stink bug species. Insecticide resistance in the redbanded stink bug varies geographically. For example, less resistance is seen in Brazil than in the U.S. because synthetic insecticides have been used longer in the U.S., providing more prolonged selection for resistant genes. “Development of resistance to insecticide chemistries is a big challenge,” George says. “New insecticide chemistries that provide long-term control need to be identified.”
In addition to synthetic insecticides, organic products for control have been explored, including neem oil and Chrysanthemum extracts.
Several categories of biological control for redbanded stink bugs have been studied. Several varieties of fungi that are toxic to insects, known as entomopathogenic fungi, are commercially available for use in pest control. While no fungi have yet been developed to specifically target stink bugs, some efficacy against stink bugs in existing varieties has been documented. For example, in a 2022 study by Portilla and colleagues, when southern green stink bugs were treated with a native Mississippi Delta strain of Beauveria, egg laying decreased by 3.5 times, and when the species was treated with a commercial strain of Beauveria, egg laying decreased by 5.4 times.
Parasitoids have been shown to be effective in reducing success of redbanded stink bugs, as well. In a study in Argentina, parasitism of redbanded stink bugs was observed by the parasitoid wasp Hexacladia smithii. Predators are another promising mode of biological control, as previous studies have found that a range of insect predators prey upon stink bugs.
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