During the past week or two, I have been inundated with questions about stink bugs and lady bugs appearing in vast numbers on interior surfaces of windows and walls. The arrival of record warmth brought a long winter to an abrupt end and the usual trickle of insects scrambling about our homes has become a flood. Where did they come from and what should you do? In previous episodes we visited brown marmorated stink bugs and lady bugs as they sought refuge and entered our homes to escape the rigors of winter outdoors. In attics, basements, and behind siding and shutters these critters hunkered down awaiting the return of spring. With sap rising in plants, stink bugs are attempting to answer Mother Nature’s wake up call to get outside and eat.
Where are they found?
The brown marmorated stink bug is a native of China, Korea, Taiwan, and Japan. Since its discovery in the late 1990’s near Allentown, PA, it has been found in Connecticut, Delaware, Idaho, Indiana, Illinois, Iowa, Maine, Maryland, Minnesota, Mississippi, Montana, New Jersey, New York, Nevada, Ohio, Oregon, South Dakota, Tennessee, Utah, Virginia, Washington, West Virginia, Wisconsin and Wyoming. In Asia, it is a serious pest of fruit trees including peaches, apples, cherries, figs, mulberries, and persimmons. More disturbing than its fondness for fruit, is its appetite for soybeans. Maryland’s soybean growers report astounding numbers of these pests in soybeans.
What do they eat?
The extent of their damage to soybeans is currently under investigation. In North America, this stinker has also been found attacking more than seventy species of plants including herbaceous annuals and perennials and many species of woody trees and shrubs. The business end of the brown marmorated stink bug is an elongated proboscis used for sucking. Stink bugs insert needle-like mouthparts into leaves and fruit, inject digestive enzymes into the plant tissue, and slurp liquefied food into their belly. Soon the stink bug’s cousins, the aphids, will resume their nefarious deeds sucking life from our trees, shrubs, and flowers. Aphids are prime food for the beneficial lady beetles that were guests in our homes during the winter. Harmonia adults have been reported to consume more than 250 aphids each day, and larvae may eat more than 1,500 during their development. They are highly beneficial when it comes to reducing populations of aphids. In addition to consuming large numbers of aphids, they will feed on adelgids, scales insects, psyllids, and many other soft-bodied insects they encounter. Like many predators, they will eat each other.
Introduction of Harmonia
Harmonia is largely arboreal, spending time in the canopies of trees and shrubs. Contrary to recent reports on national radio, the arrival and spread of Harmonia is not the result of commercial enterprises shipping mail-order beetles to homeowners. As early as 1916, the United States government made deliberate attempts to introduce Harmonia to help control aphids on crops like pecans. We are not exactly sure when the lady became established, but by the mid-1980s, it was firmly entrenched in the southern states. By 1993, it was reported in several Mid-Atlantic States, including Maryland. It is now distributed from Florida to the state of Washington.
Adults of this magnificent insect are highly variable in color and spot pattern. Their body color ranges from a pale orange to vermilion. The number of spots on the wing covers varies from 0 to 20. What can be done to control these home invaders? Ultimately, you will prevent stink bugs and lady beetles from becoming a nuisance in your household much the same way you prevent invasions of any insect of home invading pest. Eliminate points of entry around your foundation, windows, doors, and eves by caulking, screening, weather-stripping, and repair. In the case of stink bugs, remember these are invasive pests of your plants. As the little devils collect on windows, walls, and doors vacuum them up and throw the bag in the garbage. Dispatch them permanently. Unfortunately, because they eat so many types of plants and disperse readily, there is no good way to manage them in your landscape. In the case of your ally, the lady beetle, gently sweep or vacuum them up and release them outdoors where they will immediately seek food such as aphids lurking in your roses, crabapples, or pansies. Spraying pesticides indoors on windowsills or baseboards will provide no lasting relief from these visitors and it may expose you, your children, and pets to harmful residues. Stay calm and hang in there for another week or so, your winter houseguests are about to depart – at least until the end of summer.
We thank Jennifer Franciotti for providing the inspiration for this episode of Bug of the Week. To learn more about stink bugs and lady bugs in your home, please visit the web sites below or listen to the report at the following web link.