The name armyworm is given quite aptly here. If you should see one of these things, then rest not-so-assured that there will likely be hundreds more to follow, a veritable army of plant-decimating creepy crawlies.
Not exactly ideal news for any farmer. If you’ve never seen one before, we’ll show you precisely what to look for, as well as how to get rid of them if you do find that you’ve got the little pests.
What is an Armyworm?
The armyworm comes from the Noctuidae family. It is a tiny little grub-like creature that invades your garden and likes to hang out on the undersides of leaves during the day.
At night, it comes out to munch on your greenery in relative safety.
It’s extremely generously distributed across the United States, especially east of the Rocky Mountains with an expansive schedule of activity throughout the year.
These annoying, soft-bodied little creatures are found on every single continent except for Antarctica, much to the dismay of farmers everywhere.
Considered a major threat in some countries, and virtually unstoppable by passive means, this is one insect that gardeners and farmers everywhere absolutely must take seriously if they wish to protect their produce.
Identifying the Worm
Armyworms come in a wide variety of colors. Some of them are striped, others come in a variety of muddy, greenish colors.
The very important trick here is to learn which worms are army worms versus the beneficial caterpillars you’ll want to keep around.
These latter ones turn into the ever-wonderful butterflies, which help to pollinate your garden.
There are three main types you’ll want to keep your eye out for:
1. Beet Armyworm (Spodoptera exigua)
It is green and smooth in coloration with dark green pigmentation running along its top and sides. It is also known as the asparagus fern caterpillar.
The beet armyworm is native to Southeast Asia but is found in other parts of the world in countries like North America and Jamaica.
It is one of the most dangerous types of armyworms and they mostly feed on scallion, onion, alfalfa, citrus, grasses, corn, and ornamental plants.
They also feed on legumes, tomato, pepper, pea, potato, sugar beets, soybeans, sunflower, other vegetables and weeds.
2. Western Yellow Striped (Spodoptera praefica)
The Western Yellow Striped, which, just as the name implies, are dark in color with two narrow yellow lines. It is commonly found in Columbia, Utah, and California.
They generally feed on crops such as rice, corn, potato, fruits, sugar beet, alfalfa, and sweet potato.
3. Yellowstriped (Spodoptera ornithogalli)
This one can be found all around the Northeastern regions of the US and Canada. However, they have been spotted out west as well, so be vigilant.
It has a much darker color body than the spodoptera praefica, and its markings are also sharper.
The spodoptera ornithogalli commonly feed on soybeans, tobacco, corn, tomato, cotton, and alfalfa.
Other Types of Armyworms
Aside from the three we mentioned, there is actually a wide variety to keep you on your toes.
There are dozens upon dozens of varieties of armyworms and scientists estimate that well over half of them are severely destructive to all crops in general.
And with so many different species, it’s important to tell them apart from one another.
Common Armyworm (Mythimna unipuncta)
They are greyish-brown or greyish-green in color with four large dark spots on the underside of their bodies.
They are a significant menace throughout north, south, and Central America and are also common in western Asia, southern Europe, and central Africa.
The common armyworm, otherwise called true armyworm, generally feeds on grass, oats, barley, wheat, and other seed crops.
Southern Armyworm (Spodoptera eridania)
Dark green with a brownish head and normally prominent yellow or white stripes commonly found closer to the southern border with occasional pop-ups further north and east.
Crops commonly affected are cassava, capsicum, cotton, sweet potatoes, legumes, maize, tobacco, tomatoes, and other vegetables.
African Armyworm (Spodoptera exempta)
Featuring a mottled body with varying shades of green and brown, and currently a major threat to crops in both Africa and Europe.
The species mostly target corn but feeds on other crops such as rice, sugarcane, wheat, vegetables, sorghum, millet, and coconut.
Fall Armyworm (Spodoptera frugiperda)
Has as many as 53 different species in this single category, all ranging in a myriad of different colors and patterns.
It is a major threat in countries like Myanmar, Bangladesh, China, Jamaica, Thailand, Indonesia, Sri Lanka, Laos, Vietnam, Malaysia, Egypt, Japan, and Korea.
Maize is its preferred crop but it also feeds on cotton, vegetables, rice, millet, sugarcane, and other crops.
Northern Armyworm (Mythimna separata)
They mainly feed on corn, sorghum, barley, rice, and wheat.
Lawn Armyworm (Spodoptera mauritia)
Common throughout India, Australia, Malayan peninsula, and the Pacific islands, the lawn armyworm starts off with a green-pale color. It then develops a dark green back and with white and brown stripes at its sides.
This type mainly feeds on lawn grasses, oats, and barley.
Eggs are laid in clusters in protected spots that the larvae can consume once they hatch, usually grass or leaf blades.
Once hatched, the larvae become a force of nature, extremely destructive and often moving in large groups in search of food.
They grow up to about 30mm in length and after about 14-20 days, they spend 11-13 days pupating in the soil.
They then emerge as fully grown moths with a lifespan of about two weeks total, ready to lay over 1,000 eggs and begin the destructive process all over again.
Impact on Your Crops
Because of their tendency to move in large packs, these things are regular bulldozers to your crops.
Different worms feed on different things, but to narrow it down, there really isn’t any one crop that’s really safe from these worms.
Even grass isn’t safe, as the Lawn Army worm pretty much exists to mow it down. So pay close attention to the types of crops you’re growing and at what times of year.
This way, you can be best prepared for the possibility of armyworms showing their little faces in your gardens without your consent or knowledge.
Signs of The Worm
If the number of worms is large enough, the signs aren’t hard to look for.
Leaves will be chewed apart and if you’re growing soft-skinned fruits and vegetables, you might come outside to find minute little holes burrowed into them.
Worm or not, this essentially ruins your produce, as a compromised skin allows bacteria to form within. The problem is that these leaf eating worms sometimes burrow into the produce to further develop, which is just revolting on its own.
Some worms also produce a type of cottony substance on the undersides of leaves, further cuing you into the fact that they’ve been there.
The key to stopping them is to be extremely vigilant about your garden and spotting the minuscule signs before the worms become a problem that will be too big to deal with.
They’re hard to spot, so it really takes a lot of research to understand and recognize the subtle signs as to where they’ve been or where they are.
Natural Ways to Get Rid of Armyworms
So lets’ assume that you’ve discovered leaf eating worms looking like voracious caterpillars in your precious garden. Now what?
How do you get rid of these annoyances without damaging your plants or any other beneficial bugs you want to keep around?
Here, we’re going to demonstrate for you eight different natural remedies to help ease your worries about these bothersome pests.
1. Manually Remove The Worms
One of your best options for guaranteed removal and death of these annoyances is to physically go through your garden and remove them by hand as you find them.
As you go, carry around a bucket full of very hot, soapy water. As you find the worms, pick them up and drop them into the bucket.
They’ll most likely die right then and there, but leave them in the water for a little while just to be sure.
As you go around plucking the armyworms, also remove any butterfly larvae you can find.
Once all are removed and/or killed depending on the worm, use Spinosad, a natural pesticide made from two kinds of bacteria found in soil, and is also safe to spray on organic crops.
But because it doesn’t distinguish between good and bad insects, this is why you’ll want to remove anything you want to keep beforehand.
3. Predatory Wasps
You can always introduce predatory wasps into your garden, which may seem counter-intuitive, even dangerous. But trust us, this could work.
There are a few varieties you can choose from, such as the braconid wasps, the long-tailed Ichneumon wasps, and the Trichogramma wasps.
The second option actually thrives side-by-side with armyworms, with the wasps in question laying their eggs inside armyworm eggs.
The wasp larvae consume the worms before they even have a chance to hatch.
3. Neem Oil
This is a classic pest removal tactic used by gardeners everywhere. Neem oil is entirely natural and utterly safe for external use on organic crops.
It both deters and kills an immense variety of intrusive insects without even harming the ones you want to stick around your garden.
The only drawback is that rain and extreme weather mean that Neem oil has to be applied more frequently.
4. Bacillus thuringiensis (BT powder)
If you want to prevent an infestation altogether, then look into using Bacillus thuringiensis powder, or BT powder for short.
BT is a natural bacteria that will only ever do harm to caterpillars and nothing else, completely destroying their digestive tracts. This means that virtually any caterpillar is going to find itself regretting setting foot near you once this stuff takes over.
Use it early in the season to prevent the invasion of armyworms and other larvae before they even show up. But because it works best on smaller worms, it’s better to use it as early as possible for better results.
For absolute best effect, use a plant duster for a fine, even layer across every plant.
5. Regularly Check for Eggs
Perform regular checkups on your garden and especially keep an eye out for moth eggs. They’ll look like cottony little clumps on the underside of leaves.
Just give them a quick spritz with Neem oil and smear them off into a plastic baggie. Then, just toss the baggie into the trash and feel relieved that you’ve prevented a skirmish in your crops.
You can also slide the eggs off from the leaves and crush them between your fingers.
This is by far the most effective method for small farmers as it prevents the worms from hatching in the first place.
6. Turn the Soil
As you prepare to end your garden for the season, be sure to till up any soil you have left to expose whatever pupae might still be hiding.
This will reveal them to hungry predators in the area, preventing a further headache for you next season.
7. Set up Bird Baths
Birds are actually both your worst enemies and best friends as a gardener. In this case, you want them to come in.
Set out little dishes filled with water and a birdbath if you’re so inclined. Invite them in, show them what a banquet of little munchies you’ve got crawling around.
Most birds will choose worms over crops any day, so feel relieved at the truce you’ve managed to instill for the time being.
8. Homemade Worm Spray
Using such spices as garlic and hot peppers in water, this homemade insect repellent spray tends to work wonders against the armyworm.
It can be sprayed where you’ve discovered the little moochers, and its resounding success seems to be spreading rapidly among farmers all over.
9. Beneficial Nematodes
These little guys may be weird to think about introducing, but trust us, they’re a real help.
Beneficial nematodes will zone in on the enemy armyworms and quickly subdue and eliminate the threat, while not invading your garden or threatening your plants at the same time.
Plus, they’ll stick around to help prevent more army worms from staking a claim, so it’s a potentially worthy investment.
10. Bird-Attracting Plants
Take advantage of your feathered friends’ love of all things that wriggle around on their bellies.
By planting crops that attract the birds to your garden or field, you’ll encourage them to discover and devour the armyworms and larvae they find.
Birds work fast and eat faster, so whatever they find, they’ll devour quicker than you might think.
Plus, as they’re digging down to get the worms, they disrupt the soil, upsetting any eggs that might have been laid nearby, helping the process along even faster.
11. Lure in Other Beneficial Insects
This one might seem a bit weird for those on the squeamish side, but trust us, this could be one of your better options.
By luring in or releasing insects designed to tackle and devour the array of armyworms, you’re saving yourself a ton of trouble.
Bring in dragonflies with stagnant water, release praying mantis eggs into your garden, etc. Either of these bugs is the best natural pesticide you can ask for and they’re fun to watch on top of that.
Get a few of these guys into your garden and watch the army of worms vanish within days.