Cooperative
Extension
Service


University of Illinois
at
Urbana-Champaign


No. 6/May 1, 1998

Black Cutworm Update and Actual Heat-Unit Totals

Black cutworm moth captures continue to be reported by several cooperators throughout the state. Keith Fuller, Fuller Fertilizer, indicated that an intense flight occurred in the area of Adams and Hancock counties during April 26 and 27. Jeff Staley, Gallatin County, found black cutworm moths in each of his three traps on April 27 although none of the captures were intense. Jim Morrison, crop systems educator, Freeport, and Dave Feltes, IPM educator, Quad Cities, both continue to find black cutworm moths in their pheromone traps in northern Illinois; however, to date, most of the captures have been low to moderate in nature.

A quick examination of Table 1indicates that with the exception of counties in southeastern and southwestern Illinois, most areas of the state have not accumulated 300 heat units beyond intense flight dates that may have occurred as early as mid- to late March. Recall that when 300 heat units have accumulated beyond an intense flight, cutting of plants may begin to occur. Obviously, in many areas of the state, corn has yet to be planted. Inupcoming issues of this Bulletin, we will continue to provide you updates on actual heat-unit totals and projected cutting dates. Please refer to last week's Bulletin for projected cutting dates. The projections provided by Bob Scott with the Illinois State Water Survey have not changed significantly during the past week.

Thanks for your reports on black cutworm captures. We appreciate your cooperation!

Table 1. Actual heat unit accumulations (base 50 degrees F) from intense flight dates through April 27



Crop-
reporting
district and
location
Date of intense capture of black cutworm adults
in pheromone-baited traps
3/
16
3/
18
3/
20
3/
23
3/
25
3/
27
3/
30
4/
2
4/
5
4/
7
4/
9
4/
13
Southwest
Belleville306303301301300271219184179169142119
Carbondale333329325324322293235193185174145125
Southeast
Fairfield 300298292292291264211174169160135116
Rend Lake333330326326325297243203197186160139
Dixon
Springs
349345338338336308246205198188163145
West Southwest
Perry22322322322322319616113713612911898
Springfield228228228228228206173146145137123106
East Southeast
Browns-
town
267265263263263236188156153143120102
Olney25825625125125122617914914613311094
West
Monmouth1901901901901901671321081081009576
Central
Kilbourne244244243243243217177146144135122101
Peoria 22322322222222219716213113012211393
Wildlife
Park
22022021921921919515813413312411494
East
Bondville20820820620620618615212512411710489
Champaign1911911891891891711391151141089682
Stelle249249247247247223182150149140132110
Northwest
Freeport1771771771771771571219998918565
Northeast
DeKalb191191191191191170133104103979275
St. Charles1801801801801801601269696908466

Mike Gray (m-gray4@uiuc.edu), Extension Entomology, (217)333-6652