Michigan brown marmorated stink bug report for Aug. 26, 2016

Fruit and vegetable growers in the southern Lower Peninsula should be scouting for brown marmorated stink bugs this season.

The Rescue style trap must be attached to a post or tree trunk so that the “fins” touch the post/trunk – this is to make it possible for nymphs to crawl up into the trap. Traps must be baited with a lure. Photo: Michael Haas, MSU.
The Rescue style trap must be attached to a post or tree trunk so that the “fins” touch the post/trunk – this is to make it possible for nymphs to crawl up into the trap. Traps must be baited with a lure. Photo: Michael Haas, MSU.

This is the fifth weekly report of the Michigan State University Extension brown marmorated stink bug = monitoring network. Traps were checked at more than 80 sites for brown marmorated stink bug nymphs and adults using pyramid or Rescue style traps baited with commercial lures. We have now caught a total of 106 brown marmorated stink bugs in traps this season. This week, 32 nymphs but no adult brown marmorated stink bugs were captured from traps at four sites: an apple orchard in Ottawa County, an apple orchard in Kent County, and two vineyards in Berrien County.

The table below is an estimate of life stages expected at different points during the season based on using a 13.5 hour day as the biofix for brown marmorated stink bugs emerging from overwintering, 75 degree-days (DD base 14 degrees Celsius) until egglaying begins, and then another 538 DD (base 14 C) for those eggs to develop into adults.

Based on this model of brown marmorated stink bug development, we are in the midst of the transition from fifth instar nymphs into the adults that will seek shelter and overwinter. Because nymphs and adults can cause damage when they feed on fruit, growers in the southern part of the Lower Peninsula are strongly encouraged to scout for brown marmorated stink bugs – if they haven’t in the past – based on where we know it to be well-established as a nuisance pest in homes.

Traps are easy to deploy and check, but the area of influence for a single baited trap appears to be relatively small, so it is important to place them near the crop and to combine trapping with other sampling methods such as limb-jarring of fruit tree branches over beating trays or sweep-netting in orchard edges close to woodlots or riparian areas. Visual inspection of orchard edges for the presence of fruit injury, or for the insects themselves, is recommended, especially in Berrien, Van Buren, Kent, Ottawa and Genesee counties where we have known populations or where damage to fruit in commercial peach and apple orchards was reported last season.

Estimated brown marmorated stink bug life stages throughout the season

Event ->

First overwintered adults expected

Egglaying begins

Various nymph stages present from beginning of June through August

New (summer) generation adults expected

Environmental cue ->

13.5 hr day

75 DD*

(base 14 °C)

613 DD*(base 14 °C)

Benton Harbor




















Traverse City




*Degree-days were calculated by selecting individual Enviro-weather stations and creating custom reports using the Baskerville-Emin method starting with the date when day length reaches 13.5 hours in a given area.

Damage to fruit from brown marmorated stink bug feeding can be confused with several disease or nutrient deficiencies, depending on the particular fruit that is affected, so it is important to involve your local MSU Extension fruit educator to help determine what caused the damage or send samples to MSU Diagnostic Services.

Counties being monitored for BMSB in 2016 are: Allegan, Antrim, Benzie, Berrien, Clare, Genesee, Grand Traverse, Ingham, Ionia, Kalamazoo, Kent, Lapeer, Leelanau, Lenawee, Livingston, Macomb, Monroe, Oakland, Oceana, Ottawa and Van Buren. Traps are set up near apple, stone fruits (peach, plum, sweet and tart cherry), blueberry, grape, strawberry, a variety of vegetable crops and at several urban locations considered to be hot spots.

For more information about management strategies in fruit should populations reach levels that would require control, please refer to the MSU Extension Bulletin E0154, “2016 Michigan Fruit Management Guide.” To learn more about how to monitor for brown marmorated stink bugs, distinguish it from other similar-looking stink bugs and what plants it favors, visit MSU’s Brown Marmorated Stink Bug website.

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