Corn Disease: What Are Common Stalk Borers?

Is there something eating your corn plants. Perhaps it is a common corn disease. Could be papaipema nebris, the common stalk borer. Find out more.

The common corn stalk borer is known as papaipema nebris. Typically these pests are of most concern in the areas east of the Rocky Mountains in the United States, but they can cause damage to corn in other regions of the country as well.

What does it look like?

Common corn stalk borers are usually a dark brown but some can appear to be more burgundy and almost dark purple in color. Typically common stalk borers grow to the length of one inch and some common stalk borers also have stripes. The stripes or bands are always white and light reflected off these stripes may be your only indication that the worms are present, aside fromplant damage. Corn plant damage will appear as chewed or ragged leaves and the stalks may not produce ears of corn. Those stalks which are infested and do produce ears of corn will produce them either distorted or the ears will be curled and bent in shape.

How does it manifest?

Common stalk borers can spend the winter as eggs on grasses and weeds such as ragweed. After overwintering they hatch when conditions become warmer in the spring. At this point the worms feed on the leaves and bore into the sides of the stalks. A cross section of an infested plant would reveal a bored tunnel that goes upward from the original entrypoint. Once they have feed for several weeks, the worms then pupate in the soil and emerge as adult moths. The adult moths tend to be brown or grayish often looking ashen. Fortunately, common stalk borers typically only produce one generation per growing season.



What can you do about it?

Common stalk borers usually cause damage before you notice their presence. If this is the case, you are too late for any sort of chemical or other control. Your best bet is to destroy any plants that are infested and make sure that you clear all debris and nearby weeds and plants from the garden. Especially take note to clear out any nearby ragweed which is a favorite feast of common stalk borers. The following year, if you plant in the same area, you should treat the plants in early spring with an insecticide containing diazinon to kill off the insects before they can emerge and cause damage again. It is also a good idea to pretreat previously infested soil with diazinon prior to planting.

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