Wireworms wreak havoc in gardens, fields and even forests and can be fatal to any gardener.
Most of us have seen the damage caused by wireworm and many have encountered wireworm in the garden. Neither the potatoes nor the salad are safe from him. Find out what this strange-looking, tough worm is all about in our article here.
Wireworm: A short profile
When we talk about wireworms, we actually mean the large family of click beetles (Elateridae). The click beetle family includes a wide variety of small beetles whose larvae cause major damage to the underground parts of plants. The click beetles themselves do not cause any damage, they only feed on pollen and nectar.
The different species are difficult to tell apart, but you will often find the following species in your garden:
- Click beetle or click beetle (Agriotes lineatus)
- Dark Click Beetle (Agriotes obscurus)
- Click 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 backwards.
The wireworms have a yellowish-orange body color and can grow up to 2.5 cm long. They have a hard chitin shell, to which they owe their name. They have a multiannual development in the soil and have a polyphagous diet, which means they have a wide diet.
You can find out how the beetles and larvae develop in the next section.
The Wireworm Life Cycle
The click beetles lay their eggs in the ground in May or June. A female can lay up to 200 eggs in her lifetime. The clusters are found in flocks in the ground - 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 arethe wireworms stay in the ground for up to five years and wreak havoc. During this time, they can go through between 9 and 15 larval stages, depending on the species. From the second year of life, the wireworms cause damage through their food. 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 survive for up to a year without food, but then they retreat to deeper soil layers. But even when there is a drought, the larvae often retreat to deeper areas because they are very sensitive to drought.
A crucial factor in wireworm is the soil. In general, it prefers to be found on compacted and moist soil, since 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 soil?
The wireworm orients itself in the ground using CO2. Like humans, plants and their roots emit CO2, so the wireworm is attracted to the breathable roots.
Recognize Wireworm: Malicious Image
A typical symptom of soil pests is wilt. The wireworm eats at the roots of our beloved plants and as a result they can no longer absorb enough water and nutrients. As a result, the plants begin to wither. If you then dig them up, you can see the eaten roots. The wireworms gnaw at the roots or eat them off completely. Wireworms are often found in the root neck of lettuce.
Potatoes (Solanum tuberosum) can be found in the tubers feeding tunnels into the interior. The size of the tunnels varies depending on the developmental stage of the wireworm. The brown excrement of the wireworms can often be found in the tunnels. If the infestation occurs in the spring, the wireworms will eat the young sprouts. This weakens the plants, sometimes causing them to fall off completely.
To get to the bottom of the infestation, you can use a few monitoring methods: First, of course, you can dig through the soil and check if there are wireworms in your garden. Another method of surveillance is the decoy method. Lay out sliced potato halves. Dig this about 10 cm deep, mark the spot andcheck your potato halves for wireworms a week later.
Wireworm on potatoes, salad and co.
You're already looking forward to the potato harvest and what do you find after the tedious digging? Punctured and unappetizing potato tubers. So that this doesn't happen to you, we explain here briefly what you can do against the wireworm.
Can you still eat potatoes with wireworm infestation?
When the wireworms have drilled into the tubers of the potatoes, these passages then cork up. In addition, there is often feces in the boreholes. A major problem is the risk of secondary infections. This damage allows bacteria and fungi to enter and infect the potato tubers. So if you have a pierced potato whose burrows have turned black (infested with fungi or bacteria), it is better not to eat those potatoes.
Successfully fight wireworm
Fighting wireworms is a task that cannot be completed overnight. In the following section, we will show you several methods to deal with the annoying worm.
Control wireworm with pesticides
At the moment no chemical pesticides are approved against wireworms and therefore other methods of control must be used. There are experiments with the soil fungus Metarhizium, which is supposed to attack and kill the wireworms. But you can also get at the wireworm with natural measures. You'll learn 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 take advantage of these properties.
- Keep Soil Dry and Wireworms Disturb
tillage is an important key point. This can reduce the number of wireworms in the soil. By poking around in spring and/or autumn, you can disturb the annoying larvae of the click beetles and reduce the infestation somewhat. This can prevent egg laying, especially in spring. If you own a tiller, you should definitely use it to fight wireworms. The loosening is a good one tooAbility to remove moisture from the soil and dry out the larvae. So please don't overdo it with watering - especially when the wireworms are feeding.
Find a he althy balance between the amount of water needed for your plants to grow properly and the need for crop protection.
- Pay attention to crop rotation
Crop rotation in the garden should also be a 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 - since the wireworms are attracted to the expelled CO2 of the roots, they tend to attack plants with a large root system.
- Putting out he althy and strong plants
We can also do a lot in terms of culture. Pre-germinate your plants before planting them out. Thus, the plants already have a head start in development and are placed in warmer soil. He althy and strong plants are a good starting point for pest control. Using calcium cyanamide as fertilizer can reduce infestations by an estimated 20 to 30%.
- Harvest early
When harvesting potatoes, 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 burrow into the potatoes. Precocious potato varieties could also help here. 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 nematodes are easy to spread and search for their hosts in the soil. You can find out how to use nematodes as beneficial insects here.
- Sowing Marigold and Marigold
You can also fight wireworms with special plants that even make our garden pretty. Marigolds (Calendula officinalis) and marigolds (Tagetes patula) have a deterrent effect on wireworms. Simply sow the beautiful flowers between your vegetables, admire the beautiful blooms and enjoy the effect. Besides, theMarigold is a popular medicinal plant and self-seeds. So next summer she'll be popping up in your garden all by herself.
Top Wireworm Control Methods Summary:
- Keep the soil dry and loose
- Prefer plants
- Use early ripening varieties
- Harvest early
- Mixed cultures with marigold and marigold
Danger of confusion
In order to choose the right control, it is important to correctly interpret the symptoms on the plants. There can be confusion with the potato. Dry core - recognizable by small greyish spots on the surface of the tuber - looks similar to wireworm damage, but is caused by the fungus Rhizoctonia.
Read this article to find out what you should know about this fungus and how to avoid and control Rhizoctonia.