Tis’ the Season! According to a pest model for this region, the summer generation of brown marmorated stink bug (BMSB) adults start appearing this week. This pest is very mobile, and will move into fall crops readily. I caught a glimpse of an egg mass in sweet corn today (photo below), and nymphs are expected to peak within the next few days.

BMSB model for Corvallis, OR. 2017; based off Nielsen et al 2008, and available at uspest.org

 

 

 

 

 

 

 

 

 

Bell pepper, sweet corn, and tomato are all considered desirable hosts. Symptoms include sunken kernels, whitening on fruits, and spongy tissue. Rather than re-invent the wheel, I decided to direct you to some GREAT resources (see list below) for BMSB ID and management in vegetables.

BMSB egg masses are usually laid on the underside of leaves in groups of 28 eggs – count em’ and see! 🙂 – Sweet corn, Corvallis OR, 8-Sept-2017 J. Green

FOR MORE INFO:

Wiman lab page – Oregon State University – Identification, monitoring efforts, and resource list

Neilsen et al., 2008 – Rutgers University – Developmental details

BMSB info for vegetable growers – great photos of injury, explanation of life cycle, etc.

Western Corn Rootworm (WCR) is considered the most important corn pest in the U.S.1 . Most of this damage occurs in the Midwest, where corn acreage dominates the landscape. Over the last 50 years, farmers have used cultural, genetic, and chemical control strategies to lessen the effect of WCR and protect yields.

In comparison, the PNW produces a very small amount of corn (<5% of all regional farmland). Therefore, western corn rootworm has not been a problem for us so far2, and growers are much more accustomed to 12-spots (which is a western variant of the southern corn rootworm – confused yet?!)

Life histories are similar: larvae chew on roots, adult beetles attack foliage and can clip silk if populations are high enough. This interferes with pollination and can lead to poor tip fill.

poor tipfill of corn
Poor pollination during silking affects tip fill. This picture is from the Midwest, where WCR is a much bigger issue than it is in the PNW. PHOTO CREDIT: J. Obermeyer

 

Q: So why mention WCR if it’s not yet a problem here?
A: This species is worth monitoring because it has been moving westward for the past 10+ years, and could become more abundant if corn production increases in the PNW. Yellow sticky traps are great passive sampling tools for many pests, so in short…might as well.

Expansion of WCR in 10 years. Based on C.Edwards and J. Kiss (Purdue Field Crops IPM) and A. Murphy (OSU, PNW 662)

RESOURCES:

  1. Gray, M. E., Sappington, T. W., Miller, N. J., Moeser, J., & Bohn, M. O. (2009). Adaptation and invasiveness of western corn rootworm: Intensifying research on a worsening pest. Annual Review of Entomology 54: 303-321.
  2. Murphy, A., Rondon, S., Wohleb, C., and S. Hines. (2014). Western corn rootworm in eastern Oregon, Idaho, and eastern Washington. PNW Extension Publication 662. 7 pp.
WEEK 16 – Two types of rootworm are now widely present in the Valley. See this page to learn how to ID and differentiate between them. Another, third species, may be on its way. Western corn rootworm has been moving westward since 2004.

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