Insects of Corn

Crop systems support a diversity of life forms, very few of which are really pests. This means that it is essential for you to learn to recognize the various pests and to associate specific damage symptoms with what is actually causing that damage. Positive identification of pests is important because different species have vastly different life habits, and very different techniques for their management and control may be necessary.

A species that may at times become a pest is not always of economic significance. Plants, especially field crops, can generally tolerate some injury without suffering significant yield losses. The abundance of the pest is important to consider, as are the timing of its activity in relation to the development of the crop and the cost of pest control actions in relation to losses caused by the pest.

Get in the habit of checking your fields regularly (at least once a week) for the presence of large numbers of pests and damage symptoms. Consult your local Cornell Cooperative Extension office for help in learning what to look for and what to do next.

As the cost of chemical pesticides increases and the availability of some of these products become restricted in the years ahead, careful management of the crop and its pests will be called for. Insecticides should be used only when a demonstrated need arises. At other times the impact of pests can be minimized by careful selection of varieties, cultural practices, and conservation of natural enemies (parasites, predators, and diseases) of the pests.

The most important insect pests of field corn in New York are currently the western and northern corn rootworm, seed corn maggot, European corn borer, and Western bean cutworm. These pests are generally a problem over large parts of the state every year. Other insects such as cutworms, armyworms, wireworms, the potato stem borer, and the hopvine borer occasionally cause losses in isolated areas. Their numbers vary considerably from year to year and field to field. Nematodes and slugs, which are not insects, also are occasionally important.

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