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Stink bugs on soybean

Identification of several species of stink bugs (Pentatomidae)

one-spotted stink bug with a white background.
Figure 1a. Photo: Ione L. BugGuide.net. One-spotted stink bug commonly found in Minnesota soybeans.

Adults (Figures 1a, 1b, 1c, 1d)

  • Shield–shaped bodies with a triangular structure (scutellum) on their backs
  • 5–segmented antennae
  • Piercing–sucking mouth parts (proboscis)
  • Proboscis narrower than the thickness of the antennae for herbivores, and thicker than antennae for predators

Eggs

Eggs are barrel–shaped and often laid under leaves.

Nymphs

  • Smaller size and more rounded shape than adults
  • No wings or small undeveloped wings
  • Five nymphal stages (instars)
brown stink bug on a leaf.
Figure 1b. Photo: Russ Ottens, University of Georgia, Bugwood.org. Brown stink bug commonly found in Minnesota soybeans.
green stink bug eating a soybean leaf.
Figure 1c. Photo: Daren Mueller, Iowa State University, Bugwood.org. Green stink bug commonly found in Minnesota soybeans.
predatory spined soldier stink bug on a soybean leaf.
Figure 1d. Photo:Phil Sloderbeck, Kansas State University, Bugwood.org. Predatory spined soldier stink bug found in MN soybeans.

Scouting and management

Stink bugs have infrequently reached economically significant levels in Minnesota, but invasive species and reported increases in abundance of native species could result in increased infestations.

Scouting 

  • Start scouting as pods begin to develop and continue through seed development.
  • Scouting can be performed with a sweep net.
  • Stink bugs typically colonize field edges first, so counting should include edge and interior areas.

Treatment thresholds

  • Decisions are based on the combined count of nymphs (less than 1/4-inch long) and adults of all plant–feeding species.
  • Reasonable thresholds for use in Minnesota are as follows:
  • Soybean grown for grain: 10 bugs / 25 sweeps
  • Soybean grown for seed: 5 bugs / 25 sweeps

Labeled rates for insecticides should be used for treating stink bugs and follow directions on the product label.

Fields should be scouted after treatment to check for re–colonization.

brown marmorated stink bug on plain background appears to be very spotted looking.
Figure 2. Photo: S. Valley, Oregon Department of Agriculture, Bugwood.org. Brown marmorated stink bug.

Be on the lookout

Brown marmorated stink bug. Note the bands on the antennae, alternating dark–light pattern on abdomen and wing veins outlined in black.

The brown marmorated stink bug has recently invaded Minnesota. This species looks similar to some of the native species, but can be distinguished by the light–colored bands on the antennae and the alternating dark–light pattern on the edge of the abdomen (Figure 2). In addition, under close inspection, the veins of the membranous parts of the wings are outlined in black.

Natural history

Most species undergo one to two generations per year.

Most feed on various crop and wild plants.

Most overwinter as adults under leaf litter and loose bark, but some are household invaders.

stained soybean due to stink bug feeding.
Figure 3. Photo: Dr. Suhas Vyavhare, Texas A&M Agrilife Research and Extension. Injury to soybean caused by stink bug feeding.

Impacts

Prefer to feed on pods and developing seeds.

Penetrate plant tissues with proboscis, inject digestive enzymes, and remove nutrients.

Feeding causes abortion, deformation, and discoloration of seed, which can affect yield and quality (Figure 3).

Feeding can also cause delayed plant maturity ("stay–green syndrome").

 

Robert Koch, Extension entomologist 2015

Reviewed in 2015

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