Small, agile and indispensable in biological pest control are various types of predatory mites. Read this article to find out which ones are suitable for use in the garden or on the windowsill. But be careful: some predatory mites can be dangerous to humans and animals.
What are predatory mites useful for?
Predatory mites are beneficial insects used for biological pest control by controlling thrips, spider mites and fungus gnats. There are approximately 5,500 species of predatory mites, but some are parasitic and can be dangerous to humans and animals.
- There are around 5,500 different species of predatory mites.
- Some of them are very useful and can be used for biological pest control.
- In particular, spider mites, thrips and fungus gnats can be combated with their help.
- Other predatory mites are parasitic and torment dogs, cats, rabbits or birds. They definitely need to be treated.
What are predatory mites?
Predatory mites (Gamasina) belong to the subclass of mites (Acari), which includes around 50,000 different species. They belong to the zoological class of arachnids (Arachnida). There are around 5,500 different species of predatory mites worldwide, but to date only a few have been comprehensively studied scientifically. Many predatory mites live on the soil surface (epigeous, as the biologist says), but some also hunt in vegetation and can therefore be found on plants. Here they are often confused with pests. Other species, however, live largely in the ground (endogeic) and are only rarely found on the surface.
Tip
If you are not sure whether the small animals on your plants or on the terrace are beneficial or harmful insects, it is best to observe them for a while. They distinguish useful predatory mites from pests by their quick movements. The hunters are fast and constantly on the move.
Useful predatory mites – pest control without any chemicals
Some types of predatory mites prefer to hunt annoying plant pests and are therefore very suitable for biological pest control. The advantage of using the animals is that they are very effective and you don't have to use any poison. Species from these predatory mite genera are particularly suitable as beneficial insects:
- Amblyseius: Species in this genus are very suitable for controlling thrips and whiteflies. The species Amblyseius barkeri in particular is often used.
- Hypoaspis: Predatory mites such as Hypoaspis aculeifer and Hypoaspis miles feed on mosquito species whose eggs and larvae develop in the soil. They can therefore be used well against fungus gnats, for example.
- Phytoseiulus: This genus is one of the most species-rich genera of predatory mites. The species Phytoseiulus persimilis, which lives on leaves and prefers to hunt spider mites, is often used as a beneficial insect. The animals are particularly successful in wine growing and in greenhouses.
- Typhlodromus: Typhlodromus pyri also lives on leaves and preys on spider mites.
All species of predatory mites are vanishingly small
The following table shows which predatory mite species you can use against certain pests in the garden, greenhouse and on the windowsill:
| Predatory mite species | Used against: | When and how to use: |
|---|---|---|
| Amblyseius barkeri | Thrips and soft skin mites | Temperatures above 18 °C, require high humidity |
| Amblyseius cucumeris | Thrips and soft skin mites | Temperatures above 18 °C, require high humidity, for houseplants |
| Hypoaspis aculeifer | Sickness gnats, swamp fly larvae, thrips pupae, springtails, soft skin mites (common in flower bulbs) | Temperatures between 18 and 25 °C are optimal |
| Hypoaspis miles | Sad gnats, swamp fly larvae, thrips pupae, springtails | Temperatures between 18 and 25 °C are optimal |
| Phytoseiulus persimilis | Spider mites (P. p. look very similar to spider mites!) | Temperatures between 18 and 25 °C are optimal, development at 22 °C is twice as fast as that of spider mites |
| Typhlodromus pyri | Spider mites, primarily in fruit and wine growing | occur naturally in fruit trees, but can also be selectively released |
Excursus
Use predatory mites against red mites
The red bird mite is a blood-sucking parasite that is often found in bird keeping and must be fought stubbornly. A non-toxic, chemical-free method is the use of predatory mites of the species Hypoaspis miles, which can be easily used in the stable and also in the home. Incidentally, Hypoaspis miles is not only suitable for combating blood mites, but also snake mites, for example in terrariums. These predatory mites can be used at temperatures of at least 15 °C.
Buying predatory mites – this is what you should pay attention to
Now the question arises: Where do you get these useful predatory mites? You can easily order them online and have them delivered to your home by post. The different providers offer different pack sizes, from which you can choose the right one depending on the severity of the pest infestation and the size of the area to be treated. It is best to inquire about suitable delivery units before purchasing and compare the prices, which can vary considerably depending on the provider.
The predatory mites come well packaged in special granules (for example vermiculite) or in bean leaves. These contain the necessary nutrients so that the animals do not starve during their journey. As a rule, they survive delivery very well, but in rare cases the predatory mites can die, for example because they have been exposed to bitter cold for too long.
Tip
Use a magnifying glass to check whether the insects are still moving around after delivery or whether there is no movement to be seen. Detailed instructions are usually included in the packaging, as well as a brush. With this you transfer the predatory mites to the areas infected with pests.
Breeding predatory mites – This is how it works
You don't have to keep buying some species of predatory mites; you can also breed them yourself at home. This works particularly well with the quite uncomplicated species Typhlodromus pyri, which is usually used against spider mites. For successful breeding you need:
- Easily sealable plastic containers, contents 0.25 liters
- Plaster
- Activated carbon
- Food (pollen or live food, e.g. leaf mites)
- some purchased predatory mites to start with
And this is how predatory mite breeding works:
- Mix plaster of paris with some activated charcoal and water.
- Put the plaster mixture into the plastic containers.
- The filling height should be about a third.
- Let the plaster dry.
- Prick holes in the can lids with a fine needle.
- Put the predatory mites in the containers.
- Add some food using a brush.
- Seal the cans.
- Then feed the predatory mites once or twice a week.
- Once the activated carbon fades, add fresh water using a pipette.
If necessary, you can simply remove and insert the required amount of predatory mites with a brush.
Application of predatory mites
“Avoid toxic chemicals in the garden, after all, nature provides us with enough effective products.”
Sufficient insects must be exposed so that the predatory mites can also attack the spider mites
Fighting a pest infestation with predatory mites works best if you use the creatures preventatively or in the early stages. However, have thrips and spider mites spread significantly orwebs may already have developed, so predatory mites are no longer of any help: now tougher guns have to be brought out to save the plants that are so extensively infested.
So that the predatory mites can do their work, you should adhere to these rules when using them:
- Release a sufficient amount of predatory mites. For a light infestation, at least 20 of these animals per square meter of area are recommended.
- Do not leave the predatory mites in the package after delivery, but use them as soon as possible,.
- However, read the instructions provided carefully beforehand and be sure to follow the recommendations listed there.
- Some species of predatory mites are very sensitive and require a certain temperature and humidity.
- Provide appropriate conditions (especially high humidity!).
- Apply the predatory mites directly to the infected areas.
- Don't just spill them.
- Add predatory mites again after about a week so that the pests do not return.
After all pests have been eliminated, the predatory mites die or then feed on pollen and nectar. If possible, use the animals on endangered plants in the spring to prevent pest infestation.
Tip
In order for the predatory mites to successfully combat the pests, no mite or other pesticides may be applied at the same time. After all, these make no distinction between pests and beneficial insects and also kill the predatory mites.
Predatory mites as pests
Predatory mites sometimes nibble on human skin flakes
Given the large number of different species of predatory mites, there are of course not only useful ones. Some predatory mites make life difficult for humans and animals because they live parasitically on them and feed on skin cells, tissue fluids or even blood. Contrary to what is often suggested, these are different species, so you don't have to be afraid of the beneficial predatory mites in your garden.
Signs of a mite infestation
An infestation with parasitic species is often noticed through small pustules and redness on the skin, which are often confused with mosquito and other insect bites or neurodermatitis. These areas often itch. Small blisters or crusts can also form. These symptoms usually only occur sporadically in humans, as they are uninteresting as hosts for most species of mites. An exception, for example, are burrowing mites.
Treatment
Mites are often found on pets and torment them. Dogs, cats, rabbits, birds and snakes are particularly affected. The animals must be treated - if possible by a veterinarian - in order to prevent the symptoms from spreading and worsening. You should also clean the apartment thoroughly, as mite nests are often found in small cracks and crevices, but also in blankets, carpets and even clothing.
Predatory mites in dogs and cats
Predatory mites can also affect animals and humans
If your dog or cat itches and scratches itself noticeably often, there may be a mite infestation behind it. There are a whole range of mite species that torment your four-legged friend and cause similar symptoms:
- Ear mites: Otodectes cynotis, prefers to inhabit the external auditory canal or the skin around the ear. Development from egg to adult takes place exclusively in the ear canal. Indication is severe itching in the ears and ear infections.
- Predatory mites: Cheyletiella mites in particular, but also other species, can infect dogs and cats. These predatory mites are not host-specific, which is why not only Bello, but also the house cat, the child's rabbit or even you yourself can be infected. If you notice small scales on your skin or fur, which are associated with severe itching, a mite infestation is possible.
- Mange mites: Sarcoptes scabei (var. canis), also known as burrowing mites. These critters are highly contagious and cause symptoms that can be confused with an allergic reaction. The insatiable, severe itching is typical.
If you have any symptoms, you should immediately consult a veterinarian who will prescribe anti-inflammatory and itching-relieving anti-mite medications for your four-legged friend.
Excursus
Can dog mites also pass to humans?
In particular, burrowing mites, predatory mites that are more commonly found in dogs and outdoor cats, can pass to humans and cause the skin disease scabies (scabies). Caution is advised for pets suffering from sarcoptic mange! Furthermore, transmission of Cheyletiella mites from dogs to humans and to other pets, especially cats and rabbits, is possible.
Predatory mites in the apartment – what to do?
If your pets have been diagnosed with a mite infestation, it is very likely that there are mite nests in your home. Although most of the animals develop and live on the animal, adult female mites can also live outside of their host for a long time. Some types of predatory mites do not live directly on the host, but only visit it to feed. In order to keep the apartment mite-free, these measures are now necessary:
Predatory mites such as dust mites like to live in bed
- Take off the bed.
- Wash the bed waxes at 60 °C.
- Vacuum the mattress and treat it with an anti-mite agent.
- The same applies to carpets, especially high-pile varieties.
- Wash blankets and (ornamental) pillows too.
- Stuffed animals should either be washed or frozen for 24 hours.
- Air thoroughly several times a day.
- The humidity inside the apartment should not be too high.
- Close cracks and similar things in walls and floors, for example with silicone.
Frequently asked questions
What do predatory mites feed on?
What the different predatory mites eat depends on the respective species. Hunting predatory mites feed primarily on the tissue fluids of other insects, such as spider mites, thrips, fungus gnats, etc. However, they also suck eggs and larvae or, if there is not enough animal food available, feed on nectar and other plant materials. These predatory mites are very useful in the garden and are often used to combat pests.
Things are more problematic with predatory mite species that specialize in larger prey and live parasitically on dogs, cats or birds. They often feed on blood, but also on other bodily components (e.g. tissue fluid). These little animals can cause eczema and other diseases and are therefore undesirable.
Can bird mites also affect people?
As the name suggests, bird mites are predatory mites that prefer to attack poultry such as chickens, pigeons and wild birds. The red mite, a frequently encountered bloodsucker, is particularly dangerous for humans and must therefore be systematically combated.
How dangerous are predatory mites for humans?
Predatory mites trigger allergic reactions in humans and animals, which manifest themselves in extremely itchy skin rashes. But asthma or scabies caused by burrowing mites are also typical consequences of a mite infestation. Fortunately, this only applies to a few species, because only a few of the approximately 50,000 different species of mites are actually dangerous to humans.
Tip
Mattresses should be replaced every five to seven years to limit mite infestation.
