Factsheets from Pennsylvania State University Flea beetle. Survival of overwintering flea beetle adults is closely tied to temperatures during the winter months. For this reason, they are seldom a problem in the state except for in a few of the southeastern counties.
Flea beetles complete many generations during the growing season.
However, only those generations attacking seedling corn are considered of economic importance. Flea beetles causing problems occur from early May to late June. See table 1. Recommended insecticides, rates, and restrictions for corn insects. Reentry dates are in days.