Just the name wireworms strikes fear in the heart of farmers and gardeners. These pests infect a variety of crops, killing young plants in no time, and they live for years in the soil. Most conventional insecticides are no match for these insects.
Despite their bad reputation, learning about wireworms will help you take control back in your garden. Proper preventative measures can stop an infestation before it happens, so let’s take a look at what gardeners need to know about wireworms in the garden.
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What Are Wireworms?
Wireworms are destructive pests for farmers and gardeners, especially those growing corn. They quickly destroy crops, and management is difficult.
Wireworms are the larvae of click beetles, which are insects in the Elateridae family that get their name from the clicking sound they make when trying to flip themselves over.
These larvae are long and narrow, with a hard shell around their bodies. They come in colors like yellow, brown, and black, though some are more colorful. They measure between half and one-and-a-half inches in length.
There are many species and they are usually specific in which species of plants they attack. For example, corn (Melanotus communis) attack corn plants, sugarbeet attack sugarbeets (Limonius californicus), Great Basin wireworms (Selatosomus pruininus) feed on grasses.
Some are general feeders and will eat numerous different crops.
Some, like the eyed elator (Alaus oculatus) are beneficial insects that attack bad bugs in the garden.
These pests might be tiny, but they cause significant damage to young, vulnerable plants. One of the biggest problems is that wireworms stay in the larval for anywhere from two to six years; it takes a long time for them to mature.
They overwinter in the soil, moving closer to the surface when the temperatures increase.
Wireworms infect a range of plants, such as:
Wireworms are found everywhere throughout North America. They’re most common in fields and grass pastures. Females love to lay eggs in these sites. These pests cause serious damage in poorly draining areas.
Wireworms are no joke; you don’t want these pests in your garden. Gardeners must work vigilantly to prevent them from finding your garden and move quickly to stop infestations. A fight against wireworms might last for years unless you take proper steps!
The Lifecycle of Wireworms
The wireworm larvae and adult forms overwinter in the soil. In the spring, the female beetles emerge from the soil, mate, and lay eggs underground. Within four weeks, all of the eggs hatch, and the larvae start their vicious destruction of any plant nearby. An average female click beetle lays up to 100 eggs!
The larvae live underground for two to six years, continuing to feed, but most of their damage occurs in the spring when the soil temperatures are cool. They aren’t a huge fan of hot temperatures. The larvae prefer to live in moist, cool, heavy soils, sticking to the upper six inches of soil. During dry or hot weather, they’ll burrow deeper to find their preferred conditions.
The pupal stage begins in late summer and ends when the adults emerge in the spring. Typically, your garden will only see one generation per year, with a lifecycle requiring one to six years to complete.
Signs of a Wireworm Infestation
The damage that wireworms cause differs based on what plants the pests eat. On commercial corn farms, the larvae eat the germ inside the corn kernels, leaving only the seed coat.
Typically, wireworms tunnel into parts of your plants, like the roots and stems, causing wilted leaves and stunted growth. Most damage occurs when the plants are young and the weather turns cold, causing germination to slow down.
Wireworms feed on the smaller roots of older, established plants as well. This leads to stunted roots with discolorations. If you notice an older perennial that suddenly isn’t growing well and starts to wilt, you might have wireworms, especially if your plant is under stress.
Adult click beetles don’t cause plant damage, so once they evolve into their adult form, the only problem they cause is laying eggs in your soil. That doesn’t mean you can ignore them. You’ll need to address them, too, or the lifecycle continues.
How to Prevent Wireworms
Wireworms are one of the hardest pests to get rid of in your garden, so preventative measures are a must. It’s far easier to prevent these pests from entering your garden than it is to get rid of them.
Here are some suggestions to try.
Encourage Birds to Your Garden
Birds are a natural enemy for wireworms, so make your garden a space that birds enjoy hanging out: place birdhouses, feeders, and baths near your garden. Birds eat large amounts of wireworm larvae, stopping an infestation before it gets too bad.
The will also eat the adults before they can lay eggs. Birds are you friends!
Practice Crop Rotation
You should always move your plants around year to year. Planting them in the same place every time creates the ideal environment for pests. Rotating crops helps to stop pests from sticking around; most pests don’t infect all types of crops!
That means you should put your corn in one area of the garden one year and far away the next year.
Plant Later
One way to prevent damage from wireworms is to avoid planting too early in cold soils. Plant later when the soil is warmer.
Planting later speeds up germination, so your plants establish quickly and reduce the time when they’re small and vulnerable to wireworm damage.
Apply Insecticides
If you head into the garden section, you’ll find insecticides labeled for wireworm control, and they should be applied before or when you plant your garden. The bad news is that you cannot apply these insecticides once your crops are infected with wireworms.
These are meant to be preventative not a treatment.
How to Get Rid of Wireworms in Your Garden
Wireworms are a problematic pest that is hard to eliminate in your garden. Once you’re sure that wireworms are your problem, here are a few tricks that you can try to get rid of wireworms in your garden.
Cultivate The Soil
Cultivating the top six to eight inches of your garden soil should be a task every winter when you’re dealing with wireworms. Doing this exposes any egg-laying adults to unfavorable winter conditions, causing them to die.
At the same time, it exposes the pests to natural enemies that want to eat them for dinner.
You should plan garden cultivation several times before your garden season if you suspect that you might have wireworms or worry about a wireworm infestation.
Normally, too much cultivation destroys the soil structure, so we discourage it. But sometimes its the best way to go.
Dry Flour Baits
One wireworm control method is to insert dry flour baits into your garden soil using a corn planter or something similar.
Check the traps every few days. If they have two or more wireworms inside of the baits, remove them and put a new one in its place. Continue to check and replace the baits until no more wireworms are caught.
Potato Skewer Baits
If dry flour baits aren’t an option for you, cut chunks of potatoes and put them on a skewer. Put the potato skewer into the ground and pull it out one week later. If you find wireworms inside, toss the trap out out or burn it; don’t put them into your compost!
Then, insert a new bait.
Beneficial Nematodes
One of the best beneficial insects that take care of wireworms for you is beneficial nematodes. Apply these when planting if you know that wireworms live in your soil, and they’ll attack and destroy the pests in the soil. They’re highly effective.
When you buy beneficial nematodes, you need one pint to treat up to 550 square feet of planting area.
You can purchase a pack of 50 million nematodes at Amazon.
Use Pyrethrin
A last-ditch effort you can try before removing plants is making soil drenches that contain a botanical insecticide called pyrethrin. It’s somewhat effective, but it also kills off beneficial insects in your garden. This should be a last resort before removing everything.
Remove Plants
Unfortunately, if nothing works and you have infected plants in your garden, you need to remove all infected plants and dispose of them immediately. You have to take them out of your garden, or the infestation will continue.
Leave the arrow fallow for a few years and then try again, focusing on prevention methods.
