In addition to direct competition for crop seedlings next season, weeds may also provide potential overwintering sites for several corn insect pests including common stalk borer, hop-vine borer, and potato stem borer. Black cutworm, another corn insect pest, does not overwinter in the egg stage, but lays it's eggs in weedy fields in early spring. Larvae of all these insect species will move from weed species to feed on crop hosts, such as young corn, in the spring. Correct identification of the cause is necessary for taking appropriate action to avoid or manage the problem in next seasons crop. If European corn borer or stalk rots were a problem this season check hybrid standability ratings when selecting hybrids for next season.
Foliar diseases affecting large areas of fields can significantly reduce yields.
Correct diagnosis often requires professional assistance. The long, rectangular, grayish colored symptoms of GLS on foliage are very distinctive and remain evident even after corn is harvested. This disease caused significant losses in the midwest this season. In previous years, GLS has been found in isolated fields in the Delaware, Hudson, and Susquehanna River Valleys of New York and in Pennsylvania. If you find symptoms suggestive of GLS, please contact your Cornell Cooperative Extension field crop agent for positive identification and further information.