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Corn pests and diseases

Published: 09.04.2023
pest/disease type symptoms on corn control/prevention
Armyworms Pests Loose soil around the base of the plant and holes in the leaves. Handpick and destroy infected plants or treat with insecticidal soap.
Corn earworms Pests Holes in the ears of corn and silk hanging out from the ends. Use insecticides specifically labeled for corn earworms, and plant early-maturing varieties.
Cutworms Pests Cut seedlings at the base, leaving just the stem. Use cardboard or newspaper collars around the base of the plant or apply insecticide.
Fusarium Wilt Disease Yellowing and wilting of leaves, starting from the bottom of the plant. Remove infected plants, rotate crops, and use disease-resistant varieties.
Gray Mold Disease Gray mold growth on leaves and stems. Remove infected plant material and improve air circulation by spacing plants properly.
Leaf Blight Disease Brown spots on leaves, which may turn yellow before falling off. Apply fungicides and remove infected plant material.
Rootworms Pests Roots have feeding scars and the plants are stunted. Use insecticides and crop rotation.
Rust Disease Orange to reddish-brown pustules on leaves. Remove infected plant material and apply fungicides.
Stalk Rots Disease The stalks of the plants rot and turn mushy. Remove infected plant material and rotate crops.
Wireworms Pests Seedlings are killed, and older plants are stunted. Use insecticides and crop rotation.


Armyworms are a common pest that can wreak havoc on corn crops. These pests are the larvae of a moth species and can cause significant damage to plants if left unchecked. In this article, we will discuss the symptoms of armyworm infestation, how to control and prevent it.


The symptoms of armyworm infestation include irregularly shaped holes in leaves, chewed up tassels, and silks. You may also notice frass or excrement on the leaves or ground around the plant. Additionally, you may see the worms themselves - they are typically green or brown with stripes running down their bodies.

Control and Prevention

There are a few ways to control and prevent an armyworm infestation. One is to use insecticides specifically designed for armyworms - look for products containing bifenthrin, cyfluthrin, or permethrin. Another option is to introduce natural predators such as birds or parasitic wasps to your garden.

Prevention is key when it comes to armyworms. One way to prevent an infestation is by practicing good garden hygiene - remove any dead plant matter and weeds from the area around your plants. You can also plant resistant varieties of corn that are less susceptible to armyworms.

In conclusion, armyworms can be a serious threat to your corn crop but with the right prevention methods and control measures, you can keep them at bay. Keep an eye out for the symptoms of infestation and act quickly if you notice any signs.

Corn Earworms

Corn earworms, also known as tomato fruitworms, are a common pest that affects corn plants during the summer months. These worms have a brown or green body with stripes and can grow up to an inch long. They are known for their ability to cause significant damage to the corn ears, which can affect crop yields.


The symptoms of corn earworm infestation include holes in the corn ears and frass or worm excrement near the base of the ears. The presence of these pests can also cause discoloration and mold growth on the ears, making them unsuitable for consumption.

Control or Prevention

There are several ways to control or prevent corn earworm infestations. One effective method is to use insecticides, such as carbaryl or spinosad, during the early stages of ear formation. Another method is to practice crop rotation and remove any leftover debris from previous harvests to reduce the chance of overwintering pests. Additionally, using pheromone traps can help monitor and catch adult moths before they lay eggs on the corn plants.

In conclusion, by practicing proper pest management techniques, it is possible to prevent and control corn earworm infestations, ensuring a healthy and abundant corn harvest.


Cutworms are one of the most common pests that gardeners face, especially when growing corn. They are the larvae of several species of moths and can cause severe damage to young plants by cutting through the stem at ground level.

Symptoms: The most obvious symptom of cutworm infestation is wilted or dead seedlings. You may also notice partially or completely severed stems at or just below ground level. Cutworms are most active at night and will often hide in the soil during the day.

Control or Prevention: One way to prevent cutworms is to use physical barriers, such as cardboard collars or plastic cups with the bottoms removed, around each plant. These should be pushed down into the soil about an inch to prevent the cutworms from crawling underneath. You can also try sprinkling diatomaceous earth around the base of the plants, which will deter the cutworms from crawling up.

Another method of control is using biological control agents such as nematodes, which are parasitic worms that will infect and kill cutworms.

If you do find cutworms in your garden, handpicking them and placing them in a bucket of soapy water is an effective control measure. Insecticides can also be used but should be used sparingly and according to label instructions.

Overall, preventing cutworms is much easier than controlling them once they have infested your garden. So, it's best to take preventive measures early on.

Fusarium Wilt

Fusarium wilt is a common fungal disease that affects corn plants. It is caused by the fungus Fusarium oxysporum, which attacks the roots and stems of corn plants. This disease can cause significant yield losses, making it important for gardeners to be aware of its symptoms and prevention methods.


The first signs of Fusarium wilt are yellowing and wilting leaves. As the disease progresses, the lower leaves may turn brown and dry up, while the upper leaves may develop yellow streaks or spots. The stalks of affected plants may also become discolored, and the roots may show signs of rotting.

Control and Prevention

To prevent Fusarium wilt, it's important to plant disease-resistant corn varieties. Crop rotation is also essential in preventing this disease. Do not plant corn in the same location for more than two years in a row. Fungicides can be used to control Fusarium wilt, but they are most effective when applied preventatively.

If Fusarium wilt is present in your garden, remove and destroy affected plants to prevent the spread of the disease. It's also important to sanitize gardening tools and equipment to prevent further contamination.

In conclusion, Fusarium wilt can be a significant problem for corn growers. However, with proper prevention methods and early detection, it can be managed effectively.

Gray Mold

Gray mold, also known as Botrytis cinerea, is a fungal disease that affects corn plants. It can cause significant damage to the crops and is a common problem for gardeners.

Symptoms: The disease initially appears as small water-soaked spots on the leaves and stems of the corn plant. The spots quickly turn gray and fuzzy as the fungus begins to spread. The leaves may eventually wilt and die, and the corn ears may become infected as well. The fungus can cause the corn kernels to rot, reducing yield and quality.

Control or Prevention: The best way to prevent gray mold is to keep your garden clean and dry. Proper air circulation can help reduce humidity levels, which can inhibit the growth of the fungus. Avoid overhead watering, instead opt for drip irrigation to keep water off of the leaves. Remove any infected plant material immediately to prevent further spread of the fungus. Fungicides may also be used for control but should be used with caution and only as a last resort.

Overall, gray mold can be a serious problem for corn growers, but with proper prevention and control methods, it can be managed effectively.

Leaf Blight

Leaf blight is a fungal disease that commonly affects corn crops. It is caused by the fungus Helminthosporium maydis and can cause significant damage to corn plants if left untreated. The disease can survive in soil for up to two years and can spread rapidly through wind or rain.

Symptoms of leaf blight include the appearance of small, grayish-green lesions on the leaves, which eventually turn brown and produce a yellow halo. The lesions may merge, causing large areas of the leaf to die. In severe cases, the disease can affect the entire plant, causing stunted growth and reduced yield.

The best way to prevent leaf blight is to maintain good plant hygiene by removing any infected plant debris from the garden. Planting resistant varieties of corn can also help prevent the disease. If leaf blight does occur, it can be controlled through the application of fungicides. It is important to start treatment as soon as symptoms appear in order to prevent the spread of the disease.

In addition to fungicides, cultural practices such as crop rotation and proper irrigation can also help prevent leaf blight. Ensuring adequate soil drainage and avoiding overhead watering can help reduce humidity levels that promote fungal growth.

Overall, being aware of leaf blight and taking preventative measures can help ensure a successful corn harvest.


Rootworms are a type of corn pest that can cause severe damage to corn crops. These pests primarily feed on the roots of corn plants, which can lead to stunted growth, reduced yield, and even plant death. There are two types of rootworms that are commonly found in the United States: the western corn rootworm and the northern corn rootworm. Both of these pests can be challenging to control and can cause significant economic losses for farmers.

Symptoms of rootworm infestation can include wilting or yellowing of leaves, stunted growth, and reduced yield. In severe cases, entire plants may die. Prevention is key when it comes to controlling rootworms. Crop rotation, where corn is planted in different fields each year, can help reduce populations of rootworms. Additionally, using insecticides or planting corn varieties that are resistant to rootworms can also be effective.

If rootworm infestations do occur, there are insecticides available that can help control the pests. However, it is important to follow all instructions and safety precautions when using these products. Overall, by taking steps to prevent and control rootworm infestations, gardeners can help protect their corn crops and ensure a bountiful harvest.


Rust is a fungal disease that can affect various plants, including corn. It is caused by the fungus Puccinia sorghi and can cause significant damage to the crop if not controlled or prevented.


The first signs of rust are small, reddish-brown spots on the leaves. As the disease progresses, these spots grow larger and turn dark brown or black. Infected leaves may also become curled, twisted, and brittle. In severe cases, rust can cause premature leaf drop and reduce the yield of the crop.

Prevention and Control

Preventing rust is the best approach to manage this disease. Here are some tips for preventing rust in your corn plants:

  • Plant resistant varieties of corn.
  • Rotate crops to avoid planting corn in the same area year after year.
  • Keep the soil moist and avoid overhead watering.
  • Remove and destroy infected plant debris promptly.

If you already have rust in your corn plants, here are some steps you can take to control it:

  • Apply fungicides as soon as symptoms appear.
  • Remove and destroy infected plant debris promptly.
  • Consider planting resistant varieties of corn in the future.

By following these prevention and control measures, you can keep your corn plants healthy and productive, even in the presence of rust.

Stalk Rots

Stalk rot is a common disease in corn that is caused by several fungal pathogens. These fungi attack the lower part of the corn plant, causing it to weaken and eventually collapse. The disease is more prevalent during wet seasons and can cause significant yield losses if not managed properly.


Symptoms of stalk rot include discolored and soft stalks, which can easily be crushed by hand. The leaves of infected plants may also turn yellow prematurely, and the ears may drop down due to the weakened stalk.

Prevention and Control

The best way to prevent stalk rot is to plant resistant varieties and to maintain proper plant spacing to reduce moisture retention. Crop rotation and tillage practices can also help reduce the severity of the disease. If you notice symptoms of stalk rot in your corn crop, remove infected plants immediately to prevent the spread of the disease.

In conclusion, stalk rot is a serious disease that can cause significant yield losses in corn. As a gardener, it is important to be aware of the symptoms and take preventive measures to control the spread of the disease. By following good agricultural practices, you can protect your crop and ensure a healthy harvest.


Wireworms are a common pest that can cause significant damage to corn crops. These pests are the larvae of click beetles and are typically found in soil that has a high organic matter content.

Symptoms: Wireworms damage corn by feeding on the roots and stem of the plant. This can cause stunted growth, yellowing leaves, and reduced yields. In severe cases, wireworm infestations can lead to plant death.

Prevention and Control: One of the best ways to prevent wireworm infestations is to maintain good soil health by rotating crops and minimizing soil disturbance. Additionally, planting resistant corn varieties can help prevent wireworm damage.

If wireworms are already present in your corn field, there are several control options available. Insecticide treatments can be effective, but they must be applied at the right time and according to label directions. Alternatively, you can use natural control methods such as beneficial nematodes or parasitic wasps to control wireworm populations.

In conclusion, wireworms are a significant threat to corn crops, but with proper prevention and control measures, you can keep your plants healthy and productive. Remember to always follow label instructions when using insecticides and consult with a local expert for specific recommendations in your area.

Author: Michael Chen
Bio: I'm gardening specialist with a mission to empower people to grow their own fruits and vegetables. With my background in Plant Science from the University of California and experience working with farmers and community gardens, I'm dedicated to promoting sustainable agriculture practices and helping individuals achieve bountiful harvests. Let's get growing!