Projected Cutting Dates

The dates of intense captures (nine or moths captured over a 1- to 2-day period) are used to run a degree-day driven model that predicts when the first signs of cutting of corn seedlings might occur. The projections depend on historical temperature records for sites throughout Illinois. The first days of cutting activity by black cutworm larvae can be anticipated after the accumulation of 300 degree-days (base 50°F) from the date of the first intense capture. The occurrence of cutting injury also depends on other factors such as:

• presence of larvae in the field
• prevailing weather conditions
• conditions of the field

For example, a field that has not been tilled and planted and is full of weeds is attractive to egg-laying moths is also a good candidate for black cutworm damage. On the other hand, a field that has been tilled and planted usually escapes black cutworm injury.

The use of degree-day models and projected cutting dates should be used as a warning system for people to start scouting for black cutworms and signs of injury.

Return to Black Cutworm Page
Illinois Insect Monitoring Network