From BZ/dpa
Home remedies do not always help against a pest infestation. However, before resorting to chemical agents, there is one more option: we bring natural enemies of spider mites and fungus gnats into the house.
There are topics that evoke strong reactions: For example, if you fight harmful insects on houseplants with predators – i.e. other insects.
Are you not comfortable with that either? Comprehensible.
But the method is an environmentally friendly way to combat spider mites and fungus gnats, for example. Especially when otherwise the only way to go is to use chemical pesticides.
Predatory mites against spider mites
For example, the tiny predatory mites Phytoseiulus persimilis or Amblyseius californicus like to eat spider mites. The latter often make themselves comfortable on indoor plants, especially in winter. The spider mites can cause leaf loss, entire shoots are covered with fine webs.
Predatory mites, their natural enemies, can be bought in specialist shops to combat spider mites. You usually get small pieces of paper or cards with the little animals, which you then use to expose them to the plants.
Roundworms against fungus gnats
Another example of such deployable beneficial insects are nematodes. They eat the voracious larvae of fungus gnats, and in the garden also those of June beetles and vine weevils.
Nematodes are poured out with the irrigation water. The tiny roundworms then hunt the young pests in the soil.
Ichneumon wasps against moths
Ichneumon wasps are placed on small cards and sent that way Photo: picture alliance/dpa/dpa-Zentralbild
You can also take action against food and clothing moths in the same way: Ichneumon wasps can be bought on cardboard cards and placed in the infested cupboard.
In the best-case scenario, all moths will be eliminated after a few weeks.
However, all these beneficial insects cannot live a long life in the house if they are successfully combated. When their food is gone, they too perish.
Often only available online
There are a multitude of possibilities, according to Isabelle Van Groeningen, head of the Royal Garden Academy in Berlin. “Uncomplicated, and above all without danger to humans, animals or other living beings outside the specific target group.”
But the beneficial insects are not available everywhere and, according to the plant expert’s experience, have to be ordered primarily via the Internet. In addition, they are living organisms that must be added to the plants as soon as possible after delivery. According to some manufacturers, however, nematodes can be kept for a few weeks if you put them in the refrigerator.
Important when buying: Pay close attention to the name of the beneficial insects – not every species suits every pest.
“Informative websites from companies that specialize in this help when choosing beneficial insects and when to use them,” says Isabelle Van Groeningen. “A lot depends on temperature, humidity, season. And at what stage of life they are effective.”