Whether in the rain barrel, in puddles, in the watering can or in the garden pond: in the warm summer months, which bring a lot of rain, millions of mosquito larvae cavort in them. The smaller the water source, the faster it warms up – and therefore offers an ideal breeding ground for mosquitoes, which prefer to lay their eggs in warm, stagnant water. One reason for this is that the larvae need mild water temperatures in order to hatch after just a few days. It then takes up to three weeks before they are fully grown and start looking for fresh blood. During this time you have the opportunity to prevent a mosquito infestation by fighting the larvae (naturally).   

As already mentioned at the beginning, the mosquito larvae remain in the rain barrel or garden pond for several weeks after hatching. Before they then leave their breeding site, they remain on the surface of the water for a while as long as they are not yet able to fly. And that’s exactly when you can actively intervene to reduce the population – by interrupting the surface tension. This works best with olive, rapeseed or sunflower oil, alternatively dishwashing detergent also works. The best way to do this is as follows:

ATTENTION: Please do not use these two control methods in a garden pond as there are many living creatures (plants and animals) in it.

Another way to combat mosquito larvae is to use biological control agents for rain barrels, garden ponds and other bodies of water. Two preparations are mentioned here as examples which, according to the manufacturer, should not have any negative effects on other aquatic organisms such as fish, dragonflies, frogs or plants. “Neudomück mosquito-free” from Neudorff contains ten tablets, one of which is enough for 1000 liters of water and is effective for up to four weeks. Alternatively, there are Culinex tablets with a biological active ingredient (Bacillus thuringiensis israelensi) to combat mosquito larvae. One tablet should be enough for up to 50 liters of water. You can find out exactly how the two preparations are used on the packaging.

Without the addition of any aids, it is possible to control the mosquito population by manually fishing off the larvae on the surface of the water in the garden pond or rain barrel using a (preferably fine-meshed) landing net. However, since the stinging offspring move quite quickly, you won’t catch them all in one fell swoop. For this reason, it is advisable to repeat this process over and over again for several days in a row. You can dispose of the larvae in the compost.

So that you don’t even have to think about whether and how you will get rid of thousands of mosquito larvae from your rain barrels, you can take three preventive measures, such as:

Another note: If you use a pump in the garden pond, the water will remain in constant motion and should therefore be significantly less attractive to mosquitoes, which prefer stagnant water to lay their eggs.

Even if no one likes the biting pests, we would still like to emphasize that mosquitoes and their larvae are important for our ecosystem. They serve as an important source of life for many animals such as frogs, birds, spiders, newts, fish and dragonflies. “Even if they are annoying, mosquitoes and their relatives are an important node in the food web,” says Sönke Hofmann, managing director of the Nature Conservation Association of Germany. V. (NABU for short). His clear recommendation is: “If you want to fight mosquitoes, you should drain the breeding grounds instead of fogging yourself with chemicals,” advises Hofmann.

Source: NABU Bremen

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