By Mark Badertscher, OSU Extension Educator
Ohio State University Extension, Hardin County – Western Bean Cutworms were not caught in Hardin County OSU Extension traps this growing season. Four bucket type traps were placed around the county starting in July and were checked weekly for this pest by trapping the adult moth. The trapping of this agricultural crop pest is a part of a statewide OSU Extension monitoring program.
According to the OSU Department of Entomology, the Western Bean Cutworm was historically found in the western Corn Belt, where it was a common pest of dry beans and a sporadic pest of corn. Starting in the year 2000, economic damage from this pest was found on corn in Iowa and Minnesota. Since then, this pest has continued to rapidly spread eastward, reaching Ohio in 2006. Most moths have been caught in the extreme northwest or west central portion of Ohio.
The adults emerge in late June–early July after fully grown larvae overwinter inside soil chambers in the soil 3–8 inches deep. The adults are mostly dark brown and black, with three characteristic markings that distinguish them from other moths:
(1) a white stripe on the top edge of the forewing,
(2) a light brown tan colored dot, and
(3) a comma or crescent-shaped mark behind the dot. Mid-flight of the adults usually occurs in mid-July, with adult flight ending by mid to late August. There is one generation per year.
Larvae are tan in color, and can be identified by two broad stripes immediately behind the head. Other characteristics of WBCW larvae are absence of microspines on the body (unlike corn earworm) and lack of net-like marks on the head capsule (unlike corn earworm larvae). In pre-tassel corn, larvae will move to the whorl to feed on the flag leaf and unemerged tassel.
Once the tassel emerges, larvae then move to the ear, while feeding on corn pollen, leaf tissue, and silks. By the 4th instar, larvae will enter the ear through the tip, or 7th instar, larvae emerge from the ear and fall to the ground to overwinter in soil chambers. Pupation occurs in May, immediately before adult emergence.
Hardin County cooperating farmers participating in this local research were Dan Hiller, Jerry Layman, Steve Poland, and Paul Ralston. For more information on the Western Bean Cutworm, see OSU Fact Sheet FC-ENT-40-09 written by Andy Michel, Celeste Welty, Ronald Hammond, and James Eisley.
For more information, contact Mark Badertscher
OSU Extension Educator, Agriculture and Natural Resources
419-674-2297 or [email protected]
