Do you know that wireworms are pests that tend to affect agriculture?
Out of 9,000 wireworm species around the world, some tend to be serious agricultural pests that also tend to affect home gardens.
Like many other pests, it is the immature stage of the insect and not the adult that causes damage to the plants.
Moreover, it is important to note that wireworms are the long, wire-like larvae of the click beetle.
It got its name from the audible click it makes when, after being turned on its back, it swiftly flips back into the right position.
In case you detect wireworm damage in your garden, you already had them in the soil for a number of years.
These tend to have a particularly extended lifecycle from two to three up to six years.
While a good of which the larvae spend feeding on plant stems and boring into stems, roots, and tubers.
Getting rid of these pests as soon as you see them is the key to preventing damage not only this season but also in future gardening years.
It is important to note that wireworms feed on grasses, corn, grains, and potatoes, but also go after other vegetables.
Keep on reading.
What do Wireworms look like?
Being familiar with the lifecycle of this pest is just as important for their identification as their appearance.
You not only need to know what to look for but also when to look for it.
It is important to note that there are a number of different species of wireworms that attack crops.
However, they tend to share a similar lifecycle, a complete metamorphosis, from eggs to larvae to pupae to adults.
Life Cycle of Wireworms: Wireworms tend to spend the most part of their life cycle as larvae in the soil.
They tend to stay in the same location during their entire lifecycle.
Moreover, as adults, they tend to return to the spot where they hatched, which often results in multiple overlapping generations of wireworms of different sizes and ages in the same location.
In the spring, when the soil tends to warm up to 50 to 55 degrees Fahrenheit, the adult beetles tends to emerge from their overwintering location in the soil.
They then mate and over the summer, the females tend to lay eggs on the soil surface, in soil cracks, or near the roots of the plant.
They tend to lay a single egg at a time, however, on an ongoing basis and up to 300 eggs total.
Some preferred places for depositing eggs are grassy or weedy locations or fields.
During their entire life span of 9 to 12 months, the adults tend to stay mostly near the surface of the soil.
When their egg-laying is complete, the adults will die.
Depending on the temperature, the eggs will hatch after a few days to a few weeks.
It is important to note that the larvae of this pest tend to feed on seeds and underground parts of the plants for the remainder of the summer.
They then overwinter and restart their feeding the next spring.
This pattern tends to continue for two to three years until the larvae create an underground cell to pupate in the late summer.
The new beetle adults emerge from the pupa within a few weeks and will remain in the soil until the next spring.
Identifying Larvae and Adults
The newly hatched larvae tend to be white with dark brown jaws and are about 1/16 inch long.
While the grown larvae will measure about 1/2 to 11/2 inches in length and 1/8 inches in width.
After the first month, some species tend to develop a hard body shell while others tend to be soft.
Moreover, the color of the larvae will range from shiny yellow-brown or chestnut brown to tan-brown.
The body of these pests is slender, cylindrical, and jointed, with three pairs of short legs behind the head.
Also, the larvae of the different species are often identified by the pattern on the last segment of their abdomen.
The pupae tend to be about 1/2 inches long, white, soft, and very fragile, and they tend to resemble adult beetles in shape and size.
While above ground, you will only spot the adult, i.e. beetles with a hard-shelled, narrow, slender body, and 1/3 to 1/2 inches long, and are tapered towards the rear end.
It is important to note that the color ranges from brownish or reddish-brown to grayish, tan, or black.
What gives away this species is the clicking sound when the beetle turns on its back and flips itself over again.
The eggs tend to be shiny, pearly white, round, and hard to detect in the soil, even more so as they are not laid in clusters but individually.
Signs of Wireworms
It is important to note that what these pests prefer as host plants in your home garden is the grass.
Bold, wild, and cultivated grasses, both sweet corn and ornamental corn, and potatoes.
Moreover, they also tend to feed on a wide range of other vegetables like beans, beets, cabbage, carrots, cucumbers, lettuce, muskmelon, watermelon onion, leeks, parsnips peas, radishes, sweet potatoes, and flowers.
In case you suspect you have these pests, make sure to keep an eye out for wireworms when tilling or digging up the garden soil.
The larvae are often found in the upper six inches of the soil.
When the soil is too hot or too cold, however, it can burrow down further.
How deep they tend to be in the soil depends on the soil moisture.
These pests like moist and cool, which can make it tricky to find them in dry soil during the summer.
Make sure to inspect around ungerminated seeds as well as the upper 4 to 6 inches of the soil around damaged plants.
Also, check their roots and lower stems to see if larvae are present.
Poor germination rates of your vegetable crops can be a sign of wireworms eating the insides of seeds, feeding on the seeds right before, or just after germination.
The larvae also tend to feed on young seedlings, chewing small holes in the cotyledons and in the stems.
As a result, the seedlings tend to die as they are stunted or girdled.
While older plants are not spared. The larvae tend to feed on smaller plant roots, hair roots, and as well as underground parts of the stems.
This deprives them of the transport of nutrients and water.
As this attack is ongoing throughout the entire season, the plants will have no chance to recover, they will become, stunted, or withered and eventually die.
The larvae also burrow winding tunnels and channels into larger roots and taproots.
Also, edible roots and tubers can become deformed by forming a secondary root, ‘forking’.
The scarring and channels on the root surface or the insides make the plants inedible.
Causes of Wireworms
Though you can find wireworms anywhere, areas that were previously farm fields, pastures, grasslands, fallow fields, or sod are especially prone to wireworm infestation.
They are filled with host plants where click beetles lay their eggs.
Often new housing developments are built in this type of location and due to the long life cycle of wireworms, it is possible that you can see an infestation in your yard 3 to 5 years after that land was developed.
Another spot that attracts wireworms is poorly drained areas with moist, heavy soils.
If, in addition to the soil being wet, sod has been plowed under in this type of location, it can become an even more suitable breeding ground for wireworms.
As beneficial as cover crops like rye and adding organic matter are for amending the soil, they can also attract wireworms, especially if the drainage is poor.
Getting rid of Wireworms
Your best line of defense against this pest is monitoring and prevention, especially, if you had an infestation in the past.
Once wireworm larvae are feeding on your plants, they cannot be efficiently combatted with insecticides.
Bait them and Remove them by Hand: The most efficient mechanical method to remove this pest is to bait and kill them.
However, this will only work if the population is still small.
You will need to dig two trenches with germinating peas, beans, or corn and cover them with a board.
The wireworms will be attracted by the food sources and will gather in the trench.
Then remove the board after about one week and crush the wireworms.
Preventing Wireworms
Unlike other insects, due to their extensive lifecycle, wireworm infestation will not develop within a few days or weeks in a single season.
This will give you a bigger time window to prevent and control their population with preventive measures.
Improve drainage: It is important to note that wireworms tend to prefer wet soil.
Make sure to improve areas with poor drainage to deter them from settling in the garden.
Rotate Crops: Make sure to follow crop rotation in your garden beds as wireworm larvae overwinter in the soil, newly seeded crops or transplants are an easy target of this pest.
If you had a major problem with them, you may want to go one step further and abstain from growing any susceptible crops the next year, even in a different area of your garden.
Plant Later: Adjusting the planting time of vegetable crops that germinate faster in warmer weather can help to avoid wireworm damage.
The longer the seeds sit in the soil before germinating and the longer your plants take to establish, the longer they will be vulnerable to wireworm attacks.
Thus, if you wait a little longer until the soil has warmed up more, you will give the seeds a better chance of survival.
Biological Control: Using soil insecticides as little as possible will help to encourage natural predators of wireworms like ground beetles.
Another form of biological control is the introduction of Steinernema carpocapsae to the garden soil before planting.
These beneficial nematodes have shown promising results in treating areas with large wireworm populations.
Moreover, Steinernema carpocapsae is available in products for home gardens.
Insecticides: In case of major infestation or when you want to plant crops that need to be planted early in the season, apply an insecticide to fend off wireworms.
Make a note that these insecticides will need to b applied to the soil before planting.
It is important to note that insecticides against wireworms include products with bifenthrin, pyrethrins, and zeta-cypermethrin as active ingredients.
These are available for home gardens to be used in granule or liquid form.
Learn more about 9 Flower Garden Pests and How to get Rid of Them here.
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