Western Bean Cutworm Monitoring
Background and Objectives
- Western bean cutworm (Striacosta albicosta) historically occurred in cornfields of the Great Plains, but has moved into the central and eastern Corn Belt.
- Due to various factors, including pest pressure, reduced susceptibility, and insect resistance in some pest populations, products that include the Herculex® I (HX1) trait, but lack another effective mode of action for western bean cutworm are no longer labeled for control or suppression of western bean cutworm.
- Pioneer® brand Optimum® Leptra® and Optimum® AcreMax® Leptra® insect protection provide an effective mode of action for in-plant protection against western bean cutworm.
- Several factors may contribute to increased western bean cutworm populations, including mild winters, continuous corn production, reduced use of foliar insecticides in corn, and reduced or no tillage.
- A survey was conducted in 2017 to estimate western bean cutworm populations in fields throughout the Corn Belt and Northeastern U.S.
- 185 fields in Colorado, Illinois, Indiana, Kansas, Massachusetts, Michigan, Missouri, Nebraska, New York, Ohio, Pennnsylvania, Vermont, and Wisconsin
- Great Lakes IPM insect monitoring supplies were used for western bean cutworm population sampling in 2017.
- IPS-G004-12 Green Bucket Traps were placed adjacent to corn fields starting in late June to early July.
- SC-WBC L206-12 Lures were used to attract moths and HC-8001 Hercon Vaportape strips were used to kill the moths once caught.
- Moth counts were taken weekly for up to eight weeks. In areas with higher pressure moth counts were taken daily.
- During July and August, a subset of locations monitored egg masses to determined percentage of plants infested (data not reported here).
- Average total moth counts were considerably higher in fields that had been planted to corn for three or more years (Figure 1).
- Peak moth flight was recorded in mid- to late-July at most trapping locations. Peak flight did not occur until mid-August for a few locations in New York and Vermont (Figure 2).
- Western bean cutworm moths were captured at nearly all trapping locations. The highest total moth counts were recorded at locations in the historical range of western bean cutworm in Nebraska, Kansas, and Colorado (Figure 3).
Figure 1. Western bean cutworm moth counts as influenced by field corn production history in the 2017 survey.
Figure 2. Date of peak moth flight at 2017 western bean cutworm trapping locations.
Figure 3. Total moth trapping counts at 2017 western bean cutworm trapping locations.
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. 2016 data are based on average of all comparisons made in 185 locations through Nov. 1, 2017. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.
Authors: Jeff Mathesius and Mark Jeschke