Even a toddler who grabs one for the first time knows why they are called stink bugs. The shield-shaped bug releases an unpleasant odor when handled, a natural defense against certain predators. Found in most of the United States, stink bugs are a major agricultural pest in the Southeast. Using needlelike mouth parts, they suck the life out of commercial row crops like cotton, rice and soybeans, as well as vegetables, fruits and nuts. Wilted leaves, deformed plants and damaged fruit can all be symptoms that stink bugs are in the area.
University of Florida entomologist Russell Mizell has a sneaky strategy when it comes to stink bugs. It could be called ‘feeding the hand that bites you’. He has designed a rotating menu of trap crops to lure the voracious insects away from cash crops. The trap cropping system can be customized for any planting season from spring to fall. It is farm-scale neutral and will work for organic or conventional farms.
Mizell used a Southern SARE On-Farm research grant to test a myriad of potential trap crops. He was seeking plants that would provide a steady source of food that is tastier to stinkbugs than the soybeans, peaches, pecans, grains or other crops a farmer might grow. The most desirable trap plants would be unappealing to deer while being attractive to as many stink bugs and leaf-footed bugs as possible. Seeds also would have to be widely available from commercial dealers.
The tests were conducted for two growing seasons at the North Florida Research and Education Center in Quincy. Mizell’s detailed final report reads like a detective novel with a distinct process of elimination. Some plants that showed promise didn’t make the cut because they took too long to mature or didn’t reach preferred height requirements or were difficult to manage.
So what were the most successful trap crops?
For earliest spring protection (March to April in North Florida), fall-planted triticale was found to thrive in the mild Florida winter plus attract a wide variety of stink bugs. Next, buckwheat and sunflower planted in the cool soils of early spring can be ready to lure the bugs when triticale gets past its prime. Additionally, buckwheat can be planted repeatedly throughout the growing season because its early maturation makes it a good relay crop between the other trap crops. For summer-through-fall plantings, sorghum and millet can be added to buckwheat and sunflower.
In his study of stink bug behavior, Mizell found that placement of the trap crops is also important. These pests prefer to travel Tarzan-like from plant to plant rather than streaming through corridors where they could be spotted by predators, so the trap crops worked best when planted between the cash crop and whatever vegetation the bugs were migrating from.
In large fields this placement can be achieved through strip plantings. In smaller fields or home gardens, the trap crops can be planted as a perimeter band around the cash crops. On a very small scale, portable containers could be the most efficient way to use the trap crops. Mizell has access to used nursery containers, something that many growers already have or can obtain at little or no cost. Large containers (10 to 20 gallons) are big enough to plant two or three plant species in each. They hold water for a long period and they are portable by hand truck or front-end loader. Smaller ones can be moved by hand.
How many containers? “I have not quantified that in an experiment,” Mizell says, “But my experience with stink bug behavior is that placement and quality of the seeds on the plants are more critical than numbers of containers.”
He recommends adding a visual attractor to the containers, such as a 3-by-36-inch mailing tube or a 5-gallon plant container on a pole. Paint the attractors safety-yellow to make them irresistible to stink bugs as well as their natural enemies. So what to do when you lure all those stink bugs to one place? They can be netted or trapped with simple homemade devices. See Mizell’s illustrated instructions for collecting stink bugs.
Green stink bugs chow down on a millet seed head.
The orange Tachinidae fly lays its eggs on stink bugs where the larvae
parasitize both the stink bug nymphs and adults. This beneficial insect
also uses the pollen and nectar produced by trap crops.
The nymph of the southern green stink bug (Acrosternum hilare)
Okra with leaffooted bug (Leptoglossus phyllopus) and the brown
stink bug (Euschistus servus)
Putting a yellow visual trap into your trap containers
can increase the response of stink bugs, as well as
their natural enemies.
Photos courtesy Russell Mizell