This year’s corn rootworm hatch — at least in central Illinois — may be right around the corner, says University of Illinois Extension entomologist Mike Gray.
Degree-days is the best way to estimate when the rootworm hatch will happen; Gray says about half of the hatch happens when 684 to 767 degree-days have built up since the first of the year.
Gray says the state of Illinois shows between 400 and 600 degree-days since January 1, with the latter number more common in the central part of the state and lower numbers further north.
