MSU Weed Science - Department of Crop and Soil Sciences
Feb 18th, 2019

Insect Pests of Dry Beans in Michigan

Recommendations for control of insects in dry beans in Michigan are published annually in the MSU bulletin E-1582 Insect, Nematode, and Disease Control in Michigan Field Crops.. This bulletin not only lists insecticide recommendations and rates, but provides a summary of biology, sampling methods, threshold, and IPM practices for each insect. Click on the link below to access the individual chapter for dry beans.

E1582 chapter for dry bean insect pests

Potato leafhopper (PLH)

is a key yield limiting insect pest of dry beans. Both nymphs and adults secrete a salivary toxin as they feed which injures the plant beyond simple removal of plant juices. The classic symptom of PLH feeding is hopperburn (leaf yellowing) as well as leaf crinkling. Damage is already occuring to the plant even before symptoms are apparent. Therefore it is very important to monitor PLH numbers, then properly spray applications.

For more information on potato leafhopper, read the bulletin:
Potato Leafhopper in Michigan Soybean and Dry Bean

Western bean cutworm (WBC)

is a new pest of dry beans in Michigan. WBC was originally a pest of dry beans, then corn, 100 years ago in the western U.S. In the last several years, it has spread rapidly from west to east, infesting new parts of the corn belt. It is primarily a corn pest in many Midwestern states. In 2006, moths were first trapped in Michigan and by 2007, damage to corn was reported. In 2008, dry bean damage (1-5% damaged beans) occurred in central Michigan. The picture to the left shows the large holes that WBC caterpillars make as they chew into pods to feed on beans.

As an emerging threat, this insect merits watching in the state as damage spreads into the Thumb.


For more information (including trapping information), hop to the corn page on this web site or read the following bulletins:
Western Bean Cutworm Identification and Lifecycle
Western Bean Cutworm in Dry Beans

Brown Marmorated Stink Bug (BMSB)

The Brown Marmorated Stink Bug was discovered in the eastern U.S. ten years ago, and it has now reached Michigan. Like many recent invaders, BMSB is a native to Asia, and likely hitchhiked to North America in shipping containers. BMSB has numerous host plants, and thus may become a pest in many Michigan crops. Within a few years, BMSB numbers could increase and become a problem in field crops. In soybean, BMSB feeds through the developing pod, resulting in aborted or shrunken seeds. Damage to dry beans is expected to be similar. Field crops may also build large numbers of BMSB that then move into fruits and vegetables later in the season. In addition, BMSB is a fall home invader and a nuisance for home and business owners.
For information on ID and potential damage, see the bulletin: BMSB Moves Into the Midwest

Below: BMSB's have white markings on the antennae and white triangles down the abdomen. The front margins of the pronotum (the 'shoulders') are smooth, not toothed.