Corn Earworm Moth Facts & Control

Having trouble with Corn Earworms attacking your corn or tomatoes?

This page will inform you about what they are, how to identify damage as well as the best ways to eliminate them. Using a product such as Safer® Brand Garden Dust with B.T. will rid your garden of these pesky pests.


So... What's a Corn Earworm?

The corn earworm, also known as the Tomato Fruitworm, is the most devastating pest of corn in the U.S. Although the corn earworm's favorite food is corn, it will also eat tomatoes and cotton.

Adult corn earworm moths are light to dark brown in color with green eyes. The larvae are about 1"-2" in length and can vary in color depending on their instar stage.

Their colors can range from yellowish to green to brownish to red, and they may have stripes or spots on their bodies and either brown or red heads. The eggs are light and pale in color at first, but they darken as they mature.


Reproduction Patterns of Corn Earworms

Corn earworms appear in the spring. The timing of their emergence depends on the hardiness zone and climate in which they are found.

In spring, the corn earworm goes in search of food, sometimes traveling far and wide to locate it. After mating, the female corn earworm will deposit her eggs. Anywhere between 450 to 3000 eggs can be deposited in the silk of the corn by a single female. If it is too early for silk to appear on the corn, the female will deposit her eggs on the leaves of young corn plantings. You can protect your corn by using a product such as Safer® Brand Garden Dust with B.T.

Eggs generally hatch in about a week and the emerging larvae begin to travel down the ear, in search of food. The larvae will pass through several instars or mini-stages, in the next couple of weeks, after which it will drop to the ground to pupate.

Within 2-3 weeks, the adult moth will emerge and the cycle continues. Depending on the climate of the region, there can be anywhere from 1-7 generations in a typical year.


Corn Earworm's Habitat

The corn earworm can be found throughout the United States. It is found in agricultural fields and gardens where corn, tomatoes or cotton are grown. The length of time in which the corn earworm is active depends on the climate and hardiness zone.


Symptoms of Corn Earworm Damage

It is the larvae that causes the damage to crops. Holes can be found on the leaves and the excretions of the larvae can be found on the leaves and whorls.

As corn develops, the larvae will eat the kernels on the tips of the ears and proceed down the ear, eating the kernels and leaving a trail of residue along the way. Using a product such as Safer® Brand Garden Dust with B.T. can organically eliminate these destructive pests and have your corn as hearty as ever!


Results of an Corn Earworms Infestation

If the larvae attack the silk, they may prevent pollination and growth. If a larva eats its way down the ear and leaves its trail of residue, the corn is no longer edible.


Natural & Organic Controls


B.t. and pyrethrins are chemicals that can be used to help control the corn earworm. B.t. (Bacillus thuringiensis) is a safe, effective method of eliminating your garden or field of the corn earworm without environmental concerns or harm to wildlife and beneficial insects. Safer® Brand Garden Dust harnesses the power of B.T. to eliminate your pests...organically.


Safer® Brand Garden Dust kills earworm larvae, thereby preventing further damage. When the B.t. is ingested by the worm, it works as a gut rot poison that makes the worm stop feeding. The corn earworm will stop feeding immediately and die within days of malnutrition.

Carefully read and follow all directions on the product's label. B.t. is very specific and only works on caterpillars and leaf feeding worms. It will not harm beneficial insects, children, pets or wildlife. It is recommended with any pesticide to test plants for sensitivity to the product. Spray a small section of the plant in an inconspicuous area and wait 24 hours before full coverage.


B.t. is generally applied when it is a cooler time of day, preferably later in the afternoon or early in the evening since the product breaks down in sunlight and heat.

When applying pyrethrins such as Safer® Brand EndALL to infected plants, carefully read and follow all directions on the product labeling for safe and effective application. Do not spray plants in the peak of the day or when temperatures exceed 90°F

Safer® Brand offers a variety of products featuring both B.T. and Pyrethrin to give you several options to help control and eliminate this garden pest and revive your plants.

Why Choose a Natural Solution?

Natural solutions break down quickly to their natural elements. They are preferable to chemical pesticides that leave residuals where they are sprayed causing long-term detrimental effects on the environment.


Natural Predators

The parasitic wasp and green lacewings are two beneficial insects that help to control corn earworm problems. They can be attracted naturally to your cornfield or garden area where your corn is planted, and there are some companies that actually grow these insects and sell them to consumers.


The parasitic wasp lays its eggs inside the earworm's egg. These have shown success rates of over 50% and higher. When coupled with a product such as Safer® Brand Garden Dust, your garden will be free from worms and healthy. Green lacewings eat the larvae of the earworm. Planting pollen and nectar bearing flora near the corn may attract these beneficial insects. If trying to attract them doesn't work, they can also be purchased from companies who raise them.

Images courtesy of Oklahoma State University and Forestry Images. For a complete list of content sources please visit our site bibliography page

Safer® Brand brings you a variety of effective insect control products that are gentler on the environment! Most of them proudly display the OMRI Listed® organic seal and comply for use in organic gardening!