Keeping a nice yard and productive garden is fun and a labor of love. But armyworms can definitely put a cramp in your gardening style and ruin the party.
If you see one armyworm (spodoptera frugiperda) in your veggie garden, you know there are bound to be dozens (or hundreds) more.
Large numbers of thundering armyworms can decimate your crops and lawns in record time. They have voracious appetites and eat vegetation, roots, and fruit of all sorts.
The armyworm earned its name because at times they attack plants in large numbers, leaving a path of destruction behind.
How can you recognize armyworms? What can you do to prevent them and deal with them? In this article, we answer these questions and more.
Getting Rid Of Armyworms Takes Vigilance And Diligence
It’s easy to overlook these garden pests because they hide on the bottoms of leaves during the daylight hours.
They come out at night (like snails and slugs) to feast on different types of grass including Bermuda grass, garden plants, and even trees and bushes.
There are several types of armyworms which devour different crops and are active at different times of the year.
For example, the fall armyworm (Spodoptera frugiperda) species (order of Lepidoptera) is a strong flier with a wide range of host plants (over 80) but prefers grasses and turf.
It has widespread distribution from the southern United States to Argentina. A “first sighting” was reported in West and Central Africa in 2016 and now threatens Africa and Europe. [source]
Pseudaletia unipuncta known as the true armyworm is a native species with wide a distribution all over the United States east of the Rockies, but active at a different time of year than the fall armyworm. [source]
Another is the Bertha Armyworm which damages cabbage and broccoli crops and is a major problem with large outbreaks on canola crops in Canada. [source]
The Southern armyworm (Spodoptera eridania) has a wide distribution throughout Central and South America and the Caribbean. In the United States, it calls the southeastern states “home.”
It feeds on a broad range of hosts, including beet, cabbage, carrot, collard, eggplant, okra, pepper, potato, sweet potato, tomato, and watermelon. Also damaging avocado, citrus, various flowers and many weeds but does not like many grasses. [source]
With all the types of armyworms, and it is important to know how to recognize them because there are also desirable butterfly caterpillars you do not want to eliminate from your garden.
Watch for these three types of caterpillars when on the lookout for armyworms:
Beet armyworms (Spodoptera exigua) are light green. They have several vertical stripes that are thin and wavy.
These pests usually eat foliage, but if it’s in short supply they will also eat fruit.
They are especially fond of tomatoes, but they don’t usually cause a whole lot of damage to the fruit itself.
Nonetheless, you have to watch out because sometimes the larvae crawl into the fruit to develop and this is rather disgusting.
Of course, holes in your tomatoes can allow bacteria to enter the fruit and spoil it.
If you see oddly shaped holes in your fruits, look under your tomato leaves for beet armyworms.
Life Cycle Of The Beet Armyworm
The pupae overwinter in the soil. Spring females lay several mass clusters of 50 to 100 eggs and up to 600 eggs in a week. Eggs hatch in 2-3 days, spin loose webs, and spread to different parts of the plant to feed for 1-3 weeks before pupating. Moths emerge in about 1 week and live for 4-10 days. The entire life cycle is about 4-5 weeks with several generations per year. [source]
Western Yellow-Striped Armyworms
Western yellow-striped armyworms (Spodoptera praefica) is found primarily in California and Oregon.
These caterpillars are also very fond of tomato plants. You are likely to spot these caterpillars right away when taking care of your tomato plants because they feed in the daytime.
They are dark colored with a single, bright yellow, narrow line on each side.
If you don’t see the caterpillars but do see clusters of a cottony substance on your plants, suspect this type of armyworm.
The adult female parent moths lay masses of eggs on leaves, tree branches and in buildings, bundled in this cottony substance.
They can lay eggs as many as three times annually. [source]
Yellow-striped armyworms (Spodoptera ornithogalli) has a remarkably wide range.
They are very common in the northeastern US and southern Canada.
It is not unusual to find them west of the Rockies, and there have been sightings of them in some areas of the southwest, even as far west as California.
This bad bug has even been spotted on Caribbean islands and in Central and South America and Mexico.
It is most abundant in the southeastern United States where it does a great deal of damage.
Yellow-striped armyworms are dark tan with a thin yellow stripe and a thin brown stripe on each side they also have a jaunty line of black half-circles along the inner edge of each yellow stripe. [source]
Take These 10 Steps To Save Your Garden
When you identify an army worm, you have no time to lose!
Follow these ten steps to eradicate them and establish a natural Integrated Pest Management (IPM) system!
#1 – Fill a bucket half full of hot soapy water. Use dish soap, such as Dawn. It doesn’t take much, just a teaspoonful for a gallon of water will do the trick.
#2 – Manually remove the caterpillars from plants and drop them in the bucket. They should die immediately, but leave them in the water for an hour or so just to be sure.
Hot peppers and garlic sprays to repel bugs. Pyrethrum sprays because they are safe for people and toxic to plant pests.
Bug Juice is another. A Bug Juice spray is just what it sounds like, mashed up bugs blended into a slurry. Some gardeners have shared success with bug juice sprays controlling a variety of armyworms.
#3 – As you identify and remove armyworms, also look for butterfly caterpillars. If you find any, remove them from your veggie garden.
It’s a good idea to have a butterfly garden established to provide a safe haven for these caterpillars and pollinators. [source]
#4 – After executing all the armyworms you can find and removing butterfly caterpillars, use Spinosad (available at Amazon) to spray your garden.
Spinosad is a natural substance made from two soil bacterium. This pest deterrent is organic and safe to spray on food crops.
It can be somewhat harmful to beneficial insects, and it kills all sorts of caterpillars eating plants, so it is very important that you get pollinator caterpillars out of harm’s way before you spray. [source]
#5 – Embark on an IPM by introducing predatory wasps to your garden.
Their larvae hatch and consume the armyworm larvae.
The Spined Solider Bug is another natural predator attacking grubs, tent caterpillars, fall armyworms, Mexican bean beetle larvae and sawfly larvae.
#6 – Expand your natural pest management campaign by using Neem oil on a regular basis to keep armyworms and other pests under control.
This natural, horticultural oil can be used to make an excellent foliar spray and soil drench that can deter and kill a wide variety of pests (without harming beneficial insects) when used on a weekly basis.
If you are experiencing severe weather conditions (drought, excessive heat, too much sun or rain) you will need to use your foliar spray more often than once a week.
Always renew your Neem oil spray after a rain.
#7 – To prevent armyworm and other caterpillar infestation in your garden, use Bacillus thuringiensis (Bt) powder.
Bacillus thuringiensis (Bt) is a natural bacteria (not a soil insecticide) that is only toxic to caterpillars. It works by destroying their digestive systems. Bt also helps control tomato hornworms and lawn grubs in the larval stage.
It is best to dust your garden and your plants early in the season before you notice any caterpillar infestation.
Bt will work on large caterpillars, but it works best on very small caterpillars, so it is better used as a preventative than as a treatment.
You can buy Bt dust at your local garden center or online. You will also need a plant duster to apply a fine, even film. You’ll only need one or two ounces to treat fifty square feet of garden.
Don’t use Bt on your butterfly garden. Be sure to apply the product on a still day to avoid losing product by having it blow into unintended areas.
If you already have an armyworm infestation, Bt will not kill them instantly. It takes several days for the product to take effect, so don’t rely solely on Bt. Use it as a part of an integrated pest management system. [source]
#8 – Examine your garden regularly and destroy any moth eggs you see.
Look for cottony masses on the undersides of leaves.
Spray them with Neem oil spray and wipe them into a plastic bag using a cloth or paper towel. Seal the bag and dispose of it in the trash.
#9 – At the end of the growing season, turn all the soil in your garden to expose pupae so that predators can eat them.
#10 – Set up bird feeders and bird baths near your garden to attract birds. They are natural predators and love to eat army worms.
Ground-dwelling natural predators, such as toads, terrapins and box turtles also enjoy a nice meal of armyworms.
Set out dishes of water for them to drink and soak in to welcome them into your garden.
#11 – Protect crops from attacks by adding barriers of floating row covers. Use the covers in spring and fall to reduce fall armyworm invasions.
- The Armyworm is on our 30 Garden Pests to Control List
Establishing An IPM Is Key To Successful, Carefree Gardening
It is very disappointing to nurture and care for your garden, anticipate a bumper crop and then have your hopes dashed by a swarm of armyworms.
Luckily, when you develop a comprehensive, integrated plan of natural pest management, you can prevent and deal with armyworms safely and naturally.
Remember that even though Spinosad, Neem oil and Bacillus thuringiensis (Bt) are safe, natural products that are not toxic to humans, you should still wear personal protective equipment including eyewear, long sleeves and pants and gloves when applying them.
If you breathe these products in, get them in your eyes or on your skin, it could result in irritation.