INSECT PESTS of CORN
Western Bean Cutworm
WBC Trapping, 2011
As in previous years, the MSU Field Crops Entomology Program, with funding from the Corn Marketing Program of Michigan, is coordinating a trapping network for western bean cutworm moths./. This web page will update on Saturdays during the trapping season. Each dot on the WBC map represents a trap site. Similar to the USDA maps for soybean rust, the dots will change color as the number of moths per trap increases.
Note for trappers: WBC moths are double the size of a European corn borer, and will be colorful when young or freshly captured (below left). There is a distinctive white bar on the front edge of the front wing, followed by white dot and crescent marks. Old moths, and those sitting in pan traps for several days, will begin to lose color, but the white bar, dot, and crescent are still visible (below right).
Resources for WBC trapping
**Milk jug trapping instructions
**Realistic ID of WBC moths from milk jug traps
**Scentry lure SC-L206 (individual lures or packs of 25)
Great Lakes IPM, Vestaburg, MI
989-268-5693 or 800-235-0285
The western bean cutworm is a relatively new species in Michigan. Starting in the later 1990s, this pest has moved from its native range in the western U.S. into the eastern corn belt. Moths were first captured in Michigan in 2006. Damage to corn was reported in 2007, and to both corn and dry beans in 2008. Holes through the husk on the side of the ear is characteristic of larval feeding (below left) - ears look as if they have been shot. Feeding occurs on the ear tip and side (below right). Fungus and ear rot is often associated with the feeding, so there is reduction in both yield and grain quality.
Brown Marmorated Stink Bug
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 corn, BMSB feeds through the husk and damages the developing ear, resulting in unfilled or shrunken kernels. 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. See the bulletin BMSB Moves Into the Midwest for more information.
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.
Top Ten List to Reduce Trait-Torture
This season there more transgenic traits and stacks, and new brand names to add to the confusion related to biotech traits. Below is a top-ten list of things you can do to avoid mistakes at planting, and to diagnose field problems later in the season.
#10 Understand the terminology used by your seed company. Is RR the same as GT? What is the extra in Herculex Xtra? How does the Monsanto Genuity brand differ from Yieldgard?
#9 Understand the biology of each trait. What are the benefits and limitations of each trait. What level of control should you expect? Is a seed treatment part of the package?
#8 If you still do not understand the terminology and biology, call your seed dealer and ask more questions.
#7 Confirm that the seed ordered in late fall was the seed shipped this spring. Check shipping records and bag tags against your original purchase.
#6 Keep good planting records, especially in replant situations.
#5 Calculate correct refuge acres by dividing the total Bt acres by 4.
#4 Plant Bt refuge in a block or separate field instead of in strips. Alternating Bt and non-Bt corn makes it difficult to detect a problem, and strip refuges cannot be managed separately for a secondary pest problem.
#3 For herbicide traits, Ask Twice, Spray Once. For custom application, both parties should sign an agreement that at a minimum reconfirms the field(s) to be sprayed, the herbicide trait in each field, and the herbicide that will be applied. This protects both the grower and the applicator from misunderstandings that result in dead fields.
#2 Save a representative sample of your bag tags.
And the # 1 way to reduce trait torture: If you have a problem, do not wait until November to make a phone call. Contact your seed dealer, local company rep, or county extension agent promptly while the problem is still visible and fresh evidence can be gathered.