Armyworm Control: How To Get Rid of Army Worms

Army worms (also known as Fall Armyworms) are the larvae of moths and are common turf pests in yards and landscapes. As larvae, Armyworms feast on a variety of crops as well as turfgrasses. When multiplying in large numbers, they often move together toward new areas to consume food which resembles a marching army--hence the origin of their name.

Mainly found in the Southern part of the United States, Army worms like to reside on turf such as bermudagrass and infest lawns causing moderate to severe damage. Signs of trouble from Armyworms may appear in the form of brown grass which novice lawn owners mistake for the grass not getting enough sunlight or water. What actually is happening is Armyworms are chewing blades of grass, zapping the plant of it's nutrition.

If you are dealing with Army worms on your lawn or garden, our professional DIY treatment guide can help. Compiled by our staff of lawn care experts, this guide can help you step-by-step in eliminating Fall Armyworms quickly and affordably. Follow the directions provided along with using our recommended products and we guarantee success in killing the Armyworm population on your lawn.

Identification

Before you can carry out a pesticide application you will need to make sure that you are facing a Fall Armyworm infestation through identification. Careless identification can lead you to using the wrong insecticide products, which can be a waste of time and money. Listed below are common characteristics of the Fall Armyworm to easily identify them with. 

• Army worm caterpillars can either be light green or tan in their early growth stage and dark green or brown in later stages. Fully-grown larvae range between 1 to 1.5 inches long and are hairless. Their distinguishing traits are a series of green, yellow, or brown stripes down the length of their bodies.
• Army worms have brown to light brown head capsules with a Y shape. Often, Armyworms can be seen moving in large groups. Armyworm activity is usually highest from Summer to early Fall.

Use the image and description above to help you identify cutworms on your lawn. If you are having trouble confirming that the pest on your property is a cutworm, you contact us with a quality close-up photo and we will be happy to respond back to you with the pest ID as well as offer you some suggestions and products recommendations to eliminate the pest.

Inspection

Once you have properly identified the Armyworm, you can move on to inspection to observe where the most activity is occurring and where they are concentrated so you can focus your treatment on these hotspots.

When to Inspect

Observe your lawn and garden for signs of Army worms to find out where the most activity is occurring and where their eggs and larvae are concentrated. Scan your yard, specifically suspicious areas where you notice damage via discolorations or dead grass.

What to look for

What you should be looking for is the Armyworm activity on your turf or damage left by Armyworms in the form of discolored grass. Determine whether you have a small or large infestation. It's best to treat early if you find an infestation as armyworms inflict the most damage during dry and hot summer weather.

Army worms are active in the early morning, late evening and nighttime. During the day, Armyworms hide under leaf litter and thatch. To flush them out of hiding, use a solution containing 1 gallon of water and 1 tablespoon of dishwashing liquid and pour over suspected patches. If they are present, they will float to the surface within minutes.

Treatment

Our top pesticide suggestion for Armyworm control is a combination of Valar Plus Bifenthrin Granules and Supreme IT. These products are labeled to treat Armyworms and delivers a powerful 1-2 punch, providing exceptional surface and subsurface control with a long residual, effectively eliminate the entire infestation.

Before conducting chemical applications, you should make sure that you are wearing protective equipment when handling pesticides, for any chance of skin or facial contact which can be irritating or uncomfortable.

For insecticides to be effective, it is best to spray your selected product material early in the morning before 10 am as Fall Armyworms mostly feed at night.

Step 1 - Apply Valar Plus Bifenthrin Granules to Lawn

Valar Plus Bifenthrin Granules is granular insecticide that is labeled to control many turf pests, including Armyworms. Start by first calculating the square feet of your lawn or treatment area. Do this by measuring your lawn's length and width in feet, and then multiplying them together (length x width = square footage).

To treat for Army worms in your lawn, apply Valar Plus Bifenthrin Granules at a rate of 1.15 pounds per 1,000 square feet. We recommend using a push broadcast spreader to apply the granules, similar to applying fertilizer. For smaller patches of lawn, you can also use a hand spreader.

Load your spreader with the proper amount of Valar Plus Bifenthrin Granules based on your square footage. Broadcast the half the granules in parallel lines once across the area and then the other half at a perpendicular angle (like a grid pattern) so that the granules are evenly distributed over your entire lawn.

Once Valar Plus Bifenthrin Granules has been applied, it will need to be watered in to be activated. This will be done with Supreme IT in the next step.

Step 2 - Mix and Apply Supreme IT to Lawn

Supreme IT is a broad-spectrum liquid insecticide that is labeled for killing Armyworms. Supreme IT will not only activate the Valar Plus Bifenthrin Granules, but it will also kill Armyworms exposed to the product along with a long residual effect that continues to kill for up to 90 days after application.

To apply Supreme IT, simply mix water in a hand pump or hose-end sprayer then add Supreme IT at a rate of 0.18 to 0.25 fl. oz. per gallon to cover 1,000 sq. ft. You may have to apply a higher rate of 1 oz. per gallon if you have grass taller than one inch or if there is a severe infestation.

We recommend using a 20-gallon hose-end sprayer for the application to more easily make a broad treatment application throughout the entire lawn. Make sure the sprayers control valve and water pump are off and then attach the hose-end sprayer nozzle to the hose. Remove the reservoir from the nozzle and then add the proper amount of Supreme IT and the proper amount of water.

When adding the product to the reservoir, plan to use 2 gallons of water per 1,000 sq. ft. Reattach the reservoir to the nozzle securely and then begin spraying by pushing forward on the control valve after turning the water on to the hose.

Broadcast the Supreme IT evenly over your entire yard and garden as opposed to spot treating. Use a fan spray setting to get nice uniform coverage. Keep track of the amount of product in the reservoir. When it empties out, no further product will be applied.

Apply Supreme IT late in the afternoon for best control as that is when Armyworms are most active. Reapplications may be necessary until you see no further damage to your garden or the presence of Fall Armyworms has been wiped out. Make sure to postpone watering or mowing your lawn for 24 hours after application to obtain the best possible results.

Prevention

After eliminating the Fall Armyworm infestation, you will need to work to prevent the infestation from returning. Using these following preventative measures will ensure that Fall Armyworms will not return to your yard. 

• Regularly monitor your garden for any signs of damaged turf or leaves. Rake your lawn regularly to remove thatch and pick up yard debris, taking away Armyworm hiding areas.
• Maintain a routine lawn care schedule which includes proper watering (1 to 1.5 inches a week), mowing at a taller height (about 3 to 4 inches) to promote root growth.
• You should also fertilize to make sure your grass gets the proper nitrogen to stay healthy and combat pest symptoms.
• Valar Plus Bifenthrin Granules and Supreme IT can also be used as a preventative application to keep Fall Armyworms away from your property. Apply quarterly for year-long control.

Key Takeaways

What are Army Worms?

• Army worms are moth larvae that are known to feed on leaves and plants and colonizes on lawn turfgrass.

How To Kill Armyworms

• The best chemical treatment for Armyworms is Valar Plus Bifenthrin Granules and Supreme IT. Conduct a full broadcast of both products on your lawn and garden to achieve control.

Preventing Armyworm Reinfestation

• Prevent Armyworms from returning with a mixture of cultural practices and preventative treatments of Valar Plus Bifenthrin Granules and Supreme IT.