The corn flea beetle overwinters as an adult in grassy areas. High flea beetle numbers and damage occur during a cool, wet spring after a warm winter. When winter temperatures are low, poor survival results and few early season problems occur. A warm winter allows good flea beetle survival and a cool, wet spring slows corn growth during the two to three leaf stage. Corn flea beetles then have a chance to feed on the young field corn leaves for a long time.
Typical damage causes silvering and even death of the leaves.
The economic threshold for flea beetles attacking seedling corn is 5 or more per plant with significant feeding when the plants are under stress. Steward's wilt, a bacterial disease of corn may also be transmitted by the flea beetle feeding. Flea beetle predictions are made by adding the average daily temperatures for December, January and February. If the sum of these average monthly temperatures totals less than 90 F, then it is likely few flea beetles have survived. A total between 90 F and 100 F suggests flea beetle damage is possible.