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A Huge Pest of Gardening and Agriculture: Helicoverpa Zea

Granted, Helicoverpa zea is a scientific name and doesn’t sound especially ominous. For that matter, looking at a picture of this moth, a person could get the idea that it couldn’t cause much of a problem. In fact, the adults eat nectar. However, this is a major and serious pest in home gardens, agricultural fields, and wildlands. The damage isn’t done by the adults but by the larvae or caterpillars.

About Helicoverpa zea

This inconspicuous moth goes by many names, often related to the crops it destroys. To be sure, the adult moth doesn’t do the damage, the caterpillars of this moth are the stage of the moth that does enormous damage. The amount of damage that is done yearly is in the hundreds of thousands of dollars.

The common names include tomato fruitworms, cotton bollworm, and corn earworm. The damage done is due to the caterpillars eating the tomato fruits, cotton bolls, and corn kernels.

Damaging to many crops

A bigger problem with these moth larvae is that they attack a huge number of different kinds of crops and aren’t limited to corn, tomatoes, and cotton. They will also infest cucumbers, beans, lettuce, cabbage, pumpkins, potatoes, peppers, okra, cantaloupe, squash, watermelon, artichokes, and eggplants. In fact, they will eat oats, alfalfa, sorghum, sugarcane, wheat, tobacco, rice, grapes, peaches, raspberries, strawberries, roses, pears, plums, snapdragons, and many wild plants, including sunflowers, lambsquarters, purslane, ragweed, morning glory, and pigweed.

Corn earworm range

Helicoverpa zea is found throughout the US, including Hawaii and excluding Alaska. It is also found in the Carribean, in China, and in most of South America.

The problem with control

This is an insect that is quite resistant to pesticides. It has many natural predators, but studies have shown that the predators don’t make a significant impact, killing less than a percent of the total population of corn earworms. The insect is also resistant to bacteria, fungi, and diseases. The most common and successful control seems to be with the use of mineral oil.

There are a lot of other insect pests that are far better known, yet this moth probably causes more damage to agricultural crops in the US than any other. At least many hundreds of thousands of dollars worth of crops are lost to the larvae of this moth and very possibly the damage reaches into the millions.

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Written by Rex Trulove

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19 Comments

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    • Considering how long these caterpillars have been destroying crops, I doubt that they will be controlled any time soon. Some years are worse than others and some areas are harder hit, but we sometimes even have problems with this moth here in Montana.

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