Wireworm: Detect, Prevent & Combat

Wireworms are up to mischief in the garden, in the fields and even in the forests and can be fatal for any gardener.

Most of us have already seen the damage caused by the wireworm and many have come across the wireworm themselves in the garden. Neither the potatoes nor the lettuce are safe from him. Find out what this strange looking tough worm is all about here in our article.

Wireworm: A short profile

When we talk about wireworms, we actually mean the large family of click beetles (Elateridae). The snatch beetle family includes a wide variety of small beetles, the larvae of which cause great damage to the subterranean plant parts. The speed beetles themselves do not cause any damage, they only feed on pollen and nectar.

The different species are difficult to tell apart, but the following species are common in your garden:

• Rapid rock beetle or field humus rapid beetle (Agriotes lineatus)
• Gloomy humus snap beetle (Agriotes obscurus)
• Lettuce beetle (Agriotes sputator)

The adult beetles are dark in color and 9 to 12 mm in size. They are elongated and their slim body shape tapers towards the back.

The wireworms have a yellowish-orange body color and can be up to 2.5 cm long. They have a hard chitin armor, which is also what gives them their name. They have a perennial development in the soil and feed polyphagous, which means that they have a wide range of food.

You will learn how the beetles and larvae develop in the next section.

The wireworm life cycle

The snapback beetles lay their eggs in the ground in May or June. A female can lay up to 200 eggs in her lifetime. The clutches can be found in the soil in foci - not evenly distributed over the entire area. The wireworms hatch after about 4 to 5 weeks. This duration can be influenced by the weather. After that, the wireworms are in the ground for up to five years and are up to mischief. During this time, depending on the species, they can go through between 9 and 15 larval stages. From the age of two the wireworms cause damage by eating. The larvae pass through up to three in early April to mid-May, late June to mid-July and from mid-August to early October. If there is a lack of suitable food, the wireworms can do without food for up to a year, but then they withdraw to deeper soil layers. But even in drought, the larvae often retreat to deeper areas, as they are very sensitive to drought.

A decisive factor in wireworm is the soil. In general, he prefers to be found on compacted and moist soils, as the females need such undisturbed areas to lay their eggs. Our meadows are particularly suitable for this.

But how does the wireworm find its way to the plant parts in the ground?

The wireworm orients itself in the soil using CO₂. Plants and their roots, like humans, also encounter CO₂ so that the wireworm is attracted to the breathable roots.

Recognize wireworm: damage

A typical symptom of pests in the soil is wilt. The wireworm eats the roots of our beloved plants and as a result they can no longer absorb enough water and nutrients. This will cause the plants to wither. When you dig them up, you can see the roots that have been eaten away. The wireworms gnaw on the roots or eat them off completely. at Salads the wireworm is also often found in the root neck.

Both potatoes (Solanum tuberosum) can be found in the tubers feeding ducts into the interior. The size of the ducts varies, depending on the stage of development of the wireworms. The brown excrement of wireworms can often be found in the corridors. When the infestation occurs in spring, the wireworms eat the young germs. This weakens the plants so that they sometimes even fall off completely.

To get to the bottom of the infestation, you can use a few monitoring methods: On the one hand, you can of course dig through the earth and check whether there are wireworms in your garden. Another method of surveillance is the bait method. To do this, lay out cut potato halves. Dig this about 10 cm deep, mark the spot and check a week later whether wireworms have sneaked into your potato halves.

Wireworm on potatoes, lettuce and Co.

You are already looking forward to the potato harvest and what do you find after the laborious digging? Perforated and unsavory potato tubers. So that this does not happen to you, here is a brief explanation of what can be done against the wireworm.

Can you still eat wireworm potatoes?

When the wireworms have bored into the tubers of the potatoes, these tunnels then cork. In addition, there is often feces in the drill holes. A major problem is the risk of secondary infections. This damage allows bacteria and fungi to penetrate the potato tubers and infect them. So if you have a potato that has been pierced and the ducts have turned black (infected with fungi or bacteria), it is better not to eat these potatoes anymore.

Fight wireworm successfully

Fighting wireworms is a task that cannot be done overnight. In the following section we are going to show you several methods how to deal with the annoying worm.

Fight wireworm with pesticides

At the moment, no chemical pesticides are permitted against wireworm, so other methods have to be used to control it. There are experiments with the soil fungus Metarhicianwhich is supposed to attack and kill the wireworms. But you can also go to the collar of the wireworm with natural measures. You can find out how to do this in the next section.

Fight wireworm naturally

As mentioned before, the females need dense and undisturbed soil to lay their eggs and the larvae are very sensitive to drought. We can make use of these properties.

• Keep soil dry and disturb wireworms

Soil cultivation is an important point here. This can reduce the number of wireworms in the soil. By stabbing in spring and / or autumn you can disturb the annoying larvae of the click beetles and reduce the infestation somewhat. This can hinder the laying of eggs, especially in spring. If you have a tiller, you should definitely use it to fight wireworms. Loosening is also a great way to remove moisture from the soil and dry out the larvae. Therefore, please do not overdo it with watering - especially during the feeding phases of wireworms.

Find a healthy balance between the amount of water necessary for your plants to grow properly and the plant protection.

• Pay attention to the crop rotation

Crop rotation in the garden should also be a top priority. This means that you don't want your vegetables to be in the same spot every year. Certain plants are more likely to be attacked by wireworms than others. Therefore one should alternate with such plants. This includes potatoes in particular - as the wireworms from the emitted CO₂ the roots are attracted, plants with a large root system tend to be attacked.

• Expose healthy and strong plants

In terms of culture, we can also do a lot. Pre-germinate your plants before planting them out. Thus, the plants already have a development lead and are already placed in warmer soil. Healthy and strong plants are a good starting point for pest control. If calcium cyanamide is used in the fertilization, the infestation can be reduced by an estimated 20 to 30%.

• Harvest early

In the Potato harvest it is important to do this as early as possible. The longer we leave the tubers in the ground, the more time the wireworms have to dig into the potatoes. Pre-ripe potato varieties could also help here. You can find more information about the best early-ripening potato varieties.

• Insert nematodes

The use of nematodes can also promise success with wireworms. The roundworms can easily be brought out and search for their host animals in the ground. How do you Nematodes as beneficial insects to use correctly, you can find out here.

• Sow marigold and marigold

The wireworms can also be combated with special plants, which even make our garden look even more beautiful. Marigolds (Calendula officinalis) and Marigolds (Tagetes patula) have a deterrent effect on wireworms. Simply sow the beautiful flowers between your vegetables, admire the beautiful blossoms and enjoy their effect. In addition, the marigold is a popular medicinal plant and sows itself. So it will reappear in your garden by itself next summer.

The best wireworm control methods summarized:

• Keep the soil dry and loose
• Prefer plants
• Use early ripening varieties
• Harvest early
• Mixed cultures with marigold and marigold

Attention risk of confusion

In order to choose the right control, it is important to correctly interpret the symptoms on the plants. When it comes to potatoes, they can be mixed up. Dry Core - recognizable by small grayish dots on the surface of the tuber - looks in part similar to the damage caused by the wireworm, but is caused by the fungus Rhizoctonia.

What you should know about this mushroom and how to get one Avoid and control rhizoctonia can learn from this article.