The projected sum of average temperatures for December 1998, January 1999, and February 1999 is barely above 100 F for central Missouri. The corn flea beetle overwinters as an adult in grassy areas. When winter temperatures are low, poor survival results and few early season problems occur in seedling corn. A warm winter allows increased 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 as long as the weather remains cool.
Typical damage causes silvering and withering of the seedling leaves.
Flea beetle's economic threshold on seedling corn is 5 or more per plant, there is significant feeding injury, and the plants are under stress. Stewart's wilt, a bacterial disease of corn, can also be transmitted during the flea beetles feeding. Most current field corn hybrids are resistant to Stewart's wilt, but popcorn and sweet corn can still be infected. Flea beetle numbers on corn will likely be high over Central Missouri during emergence and the seedling stage. The important factor missing from this prediction is the temperature during and just after emergence.