On this page
How to identify it
- Adults are yellowish brown and narrower than most stink bugs, with a spine on each 'shoulder' that points outward and slightly forward.[3]
- Like other stink bugs, adults are shield shaped with a large triangular plate (the scutellum) on the back. Nymphs lack that plate, so use adults to confirm the species.[3]
- Nymphs of most rice-field stink bugs tend to be more colorful than the adults, and they grow larger, with more prominent wing pads, at each molt.[2]
- A disturbed bug gives off an unpleasant smell.[3][2]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Spined soldier bug | The spined soldier bug is a brown predator of other insects that does not harm sorghum heads. It has a dark spot on the center of its clear wings, and its strong shoulder spines point outward rather than forward.[3] |
| Conchuela bug | The conchuela, another stink bug that feeds on sorghum heads in Texas, has an orange tip on its scutellum and often an orange edge around the body.[3] |
Where it lives
Extension services in Arkansas, Florida and Texas treat it as a pest of rice and grain sorghum. It is the most abundant stink bug in Florida rice, and Arkansas growers have dealt with it for many years.[1][2][3]
Biology and life cycle
Adults spend the winter in grassy areas, ground litter and debris around fields, and in Arkansas they start moving to these sites in early October.[1]
In spring they feed almost entirely on the developing seeds of wild grasses, especially vasey grass and barnyardgrass, along with bearded sprangletop, broadleaf signalgrass, dallisgrass and crabgrass, and they begin reproducing soon after.[1]
Rice is the preferred host, but the bugs also feed on oats, wheat and grain sorghum. Breeding on early wild grasses lets their numbers climb before crops are available.[1]
Females lay an average of 500 to 600 eggs and up to 1,100. Eggs hatch in 4 to 11 days depending on temperature, and the nymphs pass through five stages, so egg to adult takes 14 to 30 days.[1]
Adults can live up to 3 months. Arkansas normally sees three generations a year, and four are possible when spring temperatures are moderate.[1]
They usually enter rice once it begins heading, moving in from wild grasses as those decline, and harvest pushes them from cut fields into later-maturing ones.[1]
In a 2008-2009 blacklight-trap study in Florida, rice stink bug catches peaked sharply in July.[2]
Damage and signs
- Adults and nymphs pierce developing seeds and inject saliva, which hardens into a feeding sheath on the outside of the grain.[1]
- Feeding before pollination or early in the milk stage leaves heads blank, milk-stage feeding can empty a grain completely, and feeding from milk to soft dough shrinks or discolors kernels.[1][2]
- Kernels attacked in the dough stage become shriveled, with spots from light yellow to black. This pecky rice forms when fungi enter through the feeding hole; the kernels break easily, lowering yield, grade and quality.[2][1]
- In grain sorghum, stink bugs feed directly on the developing seeds, and damaged seed is more likely to be infected by fungi or other diseases.[3]
Health risk
It feeds on grasses and grain; Arkansas, UF/IFAS and Texas A&M mention no risk to people. Like other stink bugs, it releases an unpleasant odor when disturbed.[1][2][3]
Control
Prevention
Planting so that rice heads outside the main flight period can reduce stink bug numbers, but UF/IFAS notes that frost risk and rotations with crops such as corn and sugarcane often make shifting the planting date impractical.[2]
Sanitation
Keep grassy weeds from heading in and around fields. In Florida, weedy patches of fall panicum held significantly more rice stink bugs, unmowed roadsides with heading coast cockspur held large numbers, and mowed roadsides held few. Arkansas links barnyardgrass in fields to higher counts, but warns that mowing grass along ditches can cause a sudden jump in bug numbers in adjoining fields.[2][1]
Biological control
Natural enemies help: Telenomus wasps parasitize the eggs, and assassin bugs, jumping spiders and a stink bug-hunting wasp prey on stink bugs in rice. Birds eat them too, but a Florida study that kept blackbirds out of plots found no change in stink bug numbers or pecky rice.[2][1]
Pesticides
Scout with a 15-inch sweep net from 75 percent panicle emergence through the fourth week of heading, ideally between about 7 and 11 a.m. Arkansas treats when counts reach 5 or more bugs (adults plus nymphs) per 10 sweeps in the first two weeks after 75 percent panicle emergence, or 10 per 10 sweeps during the milk and soft dough stages, and sprays in the morning.[1]
UF/IFAS notes that insecticides work but the drop in numbers may be temporary, and growers should get currently labeled products from their county extension agent.[2]
Common questions
- What is pecky rice?
- Rice kernels marked with spots from light yellow to black. The bug's saliva and feeding hole let fungi into the grain, and the spotted kernels break easily, which cuts grade and yield.[2][1]
- Why do rice stink bugs suddenly show up in a rice field?
- They build up on wild grasses in spring and move into rice as those grasses decline or get mowed. Harvest also drives them from cut fields into later ones.[1]
- Does the rice stink bug attack crops besides rice?
- Yes. Rice is its preferred host, but it also feeds on oats, wheat and grain sorghum, attacking the developing seed.[1][3]
Sources
- University of Arkansas System Division of Agriculture, Cooperative Extension Service, “Rice Stink Bug in Arkansas, FSA-7057 (D. R. Johnson, J. Bernhardt, J. Greene, G. Lorenz and G. Studebaker).” www.uaex.uada.edu/publications/PDF/FSA-7057.pdf (accessed 2026-11-08)
- UF/IFAS Extension (EDIS), “Stink Bugs in Florida Rice, IG479 (R. Cherry, October 2013).” journals.flvc.org/edis/article/download/125911/125027/203951 (accessed 2026-11-08). Archival EDIS copy hosted on the Florida Virtual Campus journal system; the PDF directs readers to EDIS for current recommendations.
- Texas A&M AgriLife Extension, “Stink Bugs (sorghum head pests), South Texas Field Crop Entomology.” agrilife.org/sca/stink-bugs-sorghum-head/ (accessed 2026-11-08)
- iNaturalist, “Oebalus pugnax taxon page (order and family).” www.inaturalist.org/taxa/295792 (accessed 2026-11-08)