As the corn grows, the beetles will eat into the side of the whorl about 1 inch above the soil surface and the plant will bend over, trapping the new leaves.
Adults feed on stem and leaf tissues of seedling corn plants.
Injured corn plants are ragged because of the notched out leaves.
If disturbed, they will drop off the plant onto the soil and become more difficult to find.
Adults overwinter beneath soil and plant debris and in clumps of some species of weeds.
In the spring, the adults emerge and begin to feed on plants such as cocklebur and early-planted corn.
Females lay eggs in clusters of 10 to 50 in weed debris or in the soil at the bases of corn plants.
In a week to 10 days, the larvae hatch and begin to feed on corn roots.
The larval period lasts for approximately 10 weeks and occurs from early May until mid-July in the central portion of the Corn Belt.
Adults emerge from the soil beginning in mid-July and after a limited feeding period, begin to secure their overwintering site. The adults are strong fliers and movement from field to field is common. (SOURCE: Southern Corn Leaf Beetles Are Active in Western Illinois, May 8, 2003, Kevin Steffey)
Scouting for southern corn leaf beetle is effective and a postemerge insecticide works well and can be tank-mixed with a herbicide.