Grass mites: protect people and dogs from bites

Grass mites can cause unpleasant stings for humans and animals. We show how you can prevent grass mite bites and whether it makes sense to combat them.

A pest that has been neglected for years and which, for once, does not infect our beloved plants but ourselves, has now become an increasing problem for some time. In addition to humans, all warm-blooded animals such as dogs, cats, horses and wild animals are potential targets of the tiny parasite. In warm summers, its stings fill dermatological clinics with patients complaining of severely itchy pustules. The culprit is a relatively close relative of the tick: what is meant is the grass mite, which occurs almost worldwide. However, only a very specific stage of development of the grass mite lives as a parasite, which is why the adult mites are completely harmless.

Profile of the grass mite

The grass mite (Neotrombicula autumnalis) is a pest that has not yet been researched much, since bites by the mite have only been increasing for a few years. Even if the pest has hardly been researched, there is a whole range of synonyms for the mite. It is also called hay mite, autumn mite and harvest mite, although the name autumn mite is very misleading, since the arachnid can infest humans and animals from March to October. During this period, the mite goes through a development cycle. From July to October, the tiny mite larvae, which don't even measure half a millimeter, hatch from eggs laid by hundreds of female grass mites. Unfortunately, it has not yet been possible to explain why the larvae develop explosively in some areas of Germany and other areas are spared. In any case, it is clear that the little beasts prefer warm temperatures and the severity of the infestation therefore increases in a warm summer. The orange-red larvae now need food to develop into an adult grass mite and look for a host to do so. Small rodents like mice are particularly fond of being parasitized, but so are pets like dogs and ourselves. The very agile larvae of the grass mite climb up 5 to 30 cm high grass and wait for their victims. From jolts while running and the exhaled CO₂ the tick-like mites are supposed to recognize their host and drop onto it.

The grass mites then look for a suitable place to inject saliva into the skin of the infested animal or human with their piercing tools. The saliva digests the skin cells around the puncture site, which is then later sucked up as a kind of cell juice by the grass mite (it doesn't suck blood like ticks do). The now full and satisfied grass mite drops from its host after just 4 to 8 hours. It then no longer poses a danger to humans and pets, because the later stages of development of the grass mite feed on the microorganisms in the garden.

Grass mite: treat bites and symptoms in humans and animals

Because the grass mite releases its saliva into the host skin when it stings, an unsightly skin reaction occurs. In the case of the trombidiosis (skin reaction to mite stings) triggered by this, the first symptoms become noticeable 4 to 36 hours after the first sting. The symptoms in humans and animals are usually expressed in the beginning by severe itching and a small red wheal develops with each bite. The itching peaks after 2 to 3 days and after 8 to 14 days at the latest the itching and the small red wheals should be gone. In the case of an unfavorable course of the disease and especially when the pustules are scratched, the puncture sites can become inflamed. At this point at the latest, a doctor should be consulted. As a rule, however, the symptoms disappear on their own and without complications.

Because the symptoms occur with a delay of up to 36 hours, the mites are usually already over the mountains when the itching starts. You don't have to worry about the whereabouts of the small grass mites. In the long term, the mites cannot survive in the apartment or in the house and also transmission from animal to animal or even to one Humans are excluded, since the grass mites parasitize only one host in their development cycle and "eat their fill" on it. So if you own a dog and a cat, you don't have to worry about the grass mites being transmitted from the cat to the dog.

With us humans, the small puncture marks, which are often on tight clothing (belt, elastic band, underwear), are quickly identified. Pets, on the other hand, need to be looked at more closely. In dogs and cats, the first signs are licking the paw and scratching the same part of the body repeatedly. The mites themselves can be seen as small orange spots on the skin, and almost any part of the body of pets can be infested. If the infestation is particularly severe and the animal is suffering too much, a veterinarian should be consulted. The doctor can treat the dog or cat with antipruritic preparations so that the animal no longer scratches the itchy areas. Here, too, infections and hair loss could otherwise occur.

You should definitely treat the bites of the grass mite. To do this, the pustules are first dabbed with a 70% strong alcohol solution. The alcohol disinfects the problem areas and kills grass mites that are still on the skin. Depending on the severity of the itching, the pustules can then be treated with an antipruritic preparation from the pharmacy. This is particularly recommended for children so that they do not scratch the affected areas of the skin too much. Incidentally, it has not yet been proven that the grass mite transmits diseases such as Lyme disease. For this reason, the grass mite, in contrast to the tick, is not considered a carrier of other diseases.

Grass mites: prevent bites by taking preventive measures

Since people, dogs and cats are sometimes plagued by severe itching for days due to the bites of the grass mite, the proximity to the grass mites should be avoided. In general, the grass mite likes to stay on lawns, in parks and meadows, i.e. wherever there is grass. With a little trick you can quickly test whether your garden has also been colonized by the unwelcome mites. A white tile or paper is simply placed on the grass. If grass mites are present, they are attracted by the light color and can be quickly identified by their orange-red color on the white background. Infested areas should not be walked on, particularly on warm days, or if this is not otherwise possible, then only at a cool time of the day.

Take precautions and contain grass mites

Of course, you can't always escape from grass mites, especially when your own garden is affected. As a garden owner, you can protect yourself by wearing rubber boots and closed clothing on infested areas and avoiding unnecessary contact with the ground. A quick shower and change of clothes after entering a meadow infested with grass mites can also help to avoid itchy bites. In addition, you should observe the following tips if you do not want to have grass mite bites on you and your pets:

• Mow the lawn regularly and dispose of the lawn clippings together with the grass mites (not on the compost!)
• So-called repellents (e.g. B. Autan) are applied so that the grass mite does not even get the taste
• Rodents ensure a proliferation of grass mites. So removing their nests and nest sites can also lead to a decline in grass mites.

Fighting grass mites with pesticides makes sense?

Combating grass mites is impractical or impractical for a variety of reasons. One reason for this is that an infestation can be detected with a white tile or piece of paper, but it is not possible to narrow down the infested area precisely. Sprays should therefore be used on a large scale and the nimble grass mites can quickly migrate back into your garden through the neighboring garden. In addition, many beneficial insects can also be killed by the sprays and a large-scale use of sprays is always associated with high costs. In addition, the grass mites do not only migrate from the neighboring gardens. Some of the grass mite larvae hide in the ground where the sprays are no longer effective. Therefore, the use of sprays, regardless of whether they are biological or chemical, is not recommended. So far there are no mature strategies to combat the grass mite effectively and in an environmentally friendly way. An interesting control approach would be the use of beneficial insects such as predatory mites. It remains to be seen whether new means and methods will be developed in the near future to make grass mite bites a thing of the past.

One way to reduce grass mites in your garden is to mow the lawn regularly. We have our best tips on the subject for you cut the lawn summarized.