As wet weather continues to delay planting in many areas of the state, people are becoming more concerned about the potential for black cutworm problems, especially in southern Illinois. "Intense" captures of black cutworm moths (nine or more moths captured in a 1- to 2-day period) began in southern Illinois in late March, and the storm fronts continue to bring migrating moths into Illinois and other midwestern states. We have received many reports of intense captures of black cutworms within the past week. The cool weather fronts that followed on the heels of our unusually warm weather during the week of April 15 were replete with migrating black cutworms. Intense captures were especially prevalent during April 19-21. Entomologists in Indiana and Missouri have also reported captures of high numbers of black cutworm moths.|
Check out "The Hines Report," information about moth captures provided weekly by Ron Hines, senior research specialist at the Dixon Springs Agricultural Center in Pope County. You can find his report on the Web at http://ipm.uiuc.edu/publications/hines-report. At the site you will find a description of Ron's moth trap line, as well as photographs of the types of traps he uses. He has provided information regarding captures of armyworms, black cutworms, and corn earworms for the week ending April 23, 2002, from the Massac County, Pope County (bottomland), Pope County (upland), and Pulaski County sites. He will update the counts weekly. You'll find in his most recent report that he had captured 24, 9, 20, and 33 black cutworm males at the four sites, respectively.
Many other people from southern and central counties also have reported intense captures of black cutworm moths:
· Randy Klenke, with Hamel Seeds in Madison County, captured 21 moths on April 21 and 22.
· Jerry Harbour and Tom Harms, with Lincoln Land FS, captured 9 to 25 moths in 1- to 2-day periods (April 8 and 9, April 19 and 20) in a series of traps in Menard and Sangamon counties.
· Students at Lincoln Land Community College, working with Matt Montgomery, Sangamon/Menard Extension Unit educator in crop systems, captured 18 moths on April 20 and 21.
· Brien Fell, with Mowers Soil Testing Plus, captured 11 moths on April 19 in Knox County.
Although they have not reported intense captures yet, Kevin Foreman, with Crop Production Services in Galesburg, has captured black cutworm moths in traps in Fulton, Knox, Mercer, and Warren counties; and Jim Morrison, Extension educator in crop systems in Rockford, has captured several black cutworm moths in traps in Stephenson County.
Many people have reported that winter annual weeds are prevalent this year, so the stage is set for black cutworm problems. Female moths are attracted to vegetation, such as winter annual weeds for oviposition. When the field is ready to be planted and the weeds are killed with herbicides, the cutworm larvae that have survived will begin feeding on emerging corn seedlings.
From previous intense captures of black cutworms, we can predict the first dates of cutting activity (fourth instars). Table 1 shows the dates of intense captures, from which Bob Scott, Illinois State Water Survey, began accumulating degree-days (base 50 deg F) and the projected dates of cutting by black cutworm larvae in certain areas, based on the closest Illinois Climate Network station. Obviously, projecting the dates of cutting by black cutworms is not an exact science, but these projections offer some guidelines for scheduling scouting activities.
We've covered most of the bases regarding scouting and making control decisions for black cutworms (Bulletin issue no. 4, April 19, 2002). Insecticides suggested as rescue treatment for control of black cutworms were provided in issue no. 3 (April 12, 2002) of the Bulletin. At this time, all we can do is urge everyone to stay alert for the earliest signs of black cutworm problems. Corn that has emerged in some areas of the state should be examined now and regularly, at least until corn has reached the 4-leaf stage. However, corn that has yet to be planted probably will be more at risk than corn that has been planted already. So, watch carefully and frequently. Don't get caught by surprise.--Kevin Steffey