Notice the distinctive black and white bands on the antennae of this brown marmorated stink bug adult on a developing blackberry fruit. (Photo: Muhammad Haseeb)
Unfortunately, the brown marmorated stink bug (Halyomorpha halys) is a new invasive pest in Florida. First specimens of the pest in Leon County were collected by scientists at the Center for Viticulture and Small Fruit Research at Florida A&M University in June of this year on chestnut and persimmon trees. The pest was later confirmed by Susan E. Halbert of Florida Department of Agriculture and Consumer Services, Division of Plant Industry.
Since its introduction into Allentown, Pennsylvania, in the mid-1990s, the pest has spread to at least 46 states. The species is native to Eastern Asia and can feed on over 300 different plants.
Since its arrival in the United States, it has caused millions of dollars of damage to several economically important crops, including vegetables, fruits, nuts, ornamentals and row crops. Additionally, it can be an extreme nuisance in and around buildings.
Physical damage to fruit crops includes pitting and scarring, sometimes leading to a mealy texture in the fruit. This injury makes the fruit unmarketable as a fresh product, and in severe cases, can even render the crop unusable for processed products. Brown marmorated stink bugs are sap-sucking insects that also feed on leaves. This causes leaf injury called stippling, which gives the leaves a spotted appearance and can interfere with photosynthesis.
In field crops, damage caused by the BMSB is not usually evident immediately upon visual inspection.The presence of the BMSB is concerning for farmers because it feeds on a large number of high-value crops and ornamental plants. Therefore, it is important to properly identify, monitor and manage this serious pest.
In North Florida, our current research focus is on pest biology, ecology and behavior leading to the development of potential longer-term integrated pest management strategies and landscape level management solutions.
Identification: An adult BMSB is 1.5 cm in length and mottled brownish-gray. Females are usually larger than the males. They have shield-shaped bodies that resemble the native brown stink bug species, but BMSB antennae have black and white bands. It has smooth shoulders, light and dark bands on the edges of its abdomen, and legs that have faint white bandings. The BMSB has five nymphal instars, or stages of growth. Before maturity, they have dark reddish eyes and a yellow-red stripe on their black abdomen. Eggs are often laid on the underside of leaves and are usually light green. They are elliptical and are often deposited in masses of 20 to 28 eggs.
Host Plants: Of the more than 300 plants on which the BMSB feeds, the crops most affected are citrus, apple, pear, peach, plum, nectarine, persimmon, lima bean, snap pea, tomato, pepper, sweet corn, field corn and soybean. Other identified host crops include raspberry, blueberry, grape, hazelnut, pecan, chestnut, cucumber, okra, cabbage, collards and hemp.
Damage and injury: In fruits, discoloration and necrotic spots appear after the stink bug has been feeding, and feeding on developing fruit my result in fruit drop. They can also act as contaminants, such as in grapevine clusters, where bugs may be crushed when fruit are pressed for juice.
In vegetables, large numbers of BMSBs can build up in open fields, resulting in fruit rot. Injury to tomatoes and peppers will produce spongy areas on the skin and tissue damage internally where feeding occurs. Feeding injury to beans may result in faded out sunken areas and deformed pods. In blueberries and blackberries, their feeding can lower the sugar content of fruit. In corn, the pest’s immature and adult stages pierce the tender kernels, which may cause them to be aborted, collapsed or discolored. In pecans, the pest causes nut drop during the water stage and black spots on kernels at harvest. Unfortunately, most producers do not realize the kernel damage until harvest.
In the winter, the pest invades dwellings in large numbers to seek overwintering sites and can be a nuisance.
Monitoring and Detection: Monitoring for the BMSB can be accomplished several ways, including using beat sheets, pheromone traps and visual observation. On farms, the likelihood of finding the BMSB is increased when monitoring efforts are focused on preferred habitats adjacent to the crop and crop borders. Pheromone trapping can be used effectively to detect the BMSBs. One that works well for this stink bug is a four-foot tall yellow pyramid-shaped trap that has fins tapering up to a collection jar. The stink bugs land on the fins and crawl toward the pheromone lure and get trapped in the collection jar.
Biology and Ecology: Before the winter, BMSB adults aggregate in large numbers on the sides of buildings or on perennial trees. Then, they move and hide in the protected places and overwinter in adult stages. Adult bugs become active in the spring, feed for about two weeks, and then start mating. The female begins to lay eggs in clusters of 20 to 28 with a range of 212 to 486 per lifetime. In the mid-Atlantic, there are one to two generations per year. The number of generations in various ecological zones of Florida is unknown; however, more generations generally can occur in warmer regions.
Pest Management Strategies: Managing this serious pest species is challenging because there are only a few effective pesticides that are labeled for control. Pheromone traps could be used to reduce pest density, along with encouraging predators and parasitoids such a tachinid fly, samurai wasps, assassin bugs, earwigs and green lacewing larvae.
The BMSB is not harmful to people, houses or pets. They do not bite, sting, suck blood or spread any animal diseases. Also, the species do not bore or feed on any wooden structures. Indoor sprays are not recommended due to their ineffectiveness. The best possible pest control for dwellings is sealing any possible entry points of bugs and using screens on doors and windows.
Muhammad Haseeb is an assistant professor of entomology, Center for Biological Control, College of Agriculture and Food Sciences, Florida A&M University and is a volunteer writer for UF/IFAS Extension Leon County, an Equal Opportunity Institution. For gardening questions, email the extension office at [email protected]
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