This year's weather patterns could create problems for growers who have planned on using total postemergence programs in corn.

The cool temperatures experienced in early May resulted in very slow emergence of corn, allowing cool-season weeds (lambsquarters, smartweed, giant ragweed, woolly cupgrass, and others) to get further ahead of the crop than usual. In many fields these weeds will need to be treated in the next week while corn is still relatively small.

These fields also will have a greater potential for problems with late flushes of weeds due to the long period between herbicide application and development of the crop canopy. Priority should be placed on controlling those weeds present now, and deal with late flushes at a later date if problems arise.