Especially in the flower pot, many hobby gardeners think their darlings are well protected against pests and other dangers. But what do you actually do when you find grubs in the plant pot?
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Are grubs harmful?
Insect larvae are generally referred to as grubs, which develop as maggots in the ground after laying their eggs. Although in the common opinion of hobby gardeners every grub is harmful and should be destroyed, this view is not entirely correct. Because countless maggots live in the soil without affecting the plants in any way. On the other hand, animals that feed on the roots of living plants are harmful. If the roots are eaten off, the plants can neither obtain water nor nutrients and will sooner or later die. The typical harmful grubs are the root-eating maggots of:
- Maikäfern (Melolontha)
- Brachkäfern (Amphimallon solstitiale)
- Blatthornkäfern (Phyllopertha horticola)
Recognize grubs in the flower pot
It is not so easy to recognize the animals even in the flower pot. Since the maggots are below the surface and near the roots, the sight of an animal on the surface of the earth is like chance with a chance of winning the lottery. Instead, you recognize the infestation primarily by the effects. These are weakened plants with drooping leaves and withered shoots. If these consequences cannot be explained by incorrect care or visible diseases, the probability of root eaters in the flower pot is very high.
Combat pests effectively
Now, of course, there is the possibility of using chemical agents to combat the pests. However, the chemistry also affects the soil and ultimately the plant to be protected. Better are therefore natural ways to fight the annoying maggots.
collect larvae
The easiest way to get rid of the animals is if your plant has rather loose, widely spaced roots:
- Let the floor dry well
- Pull the root ball out of the flower pot
- Shake off soil over newspaper, tarpaulin or similar
- Rinse the root ball with a strong jet of water
- Collect and discard caterpillars
- Check root system for remaining animals, rinse again if necessary
- Replant the plant with fresh potting soil
Water
With a particularly dense root network, you will not achieve comprehensive success with the variant of shaking off and rinsing described above. Because the dense root fibers enable the animals to continue to settle inside the root ball and to resist stubborn attempts to remove them. It is often difficult or even impossible to recognize the animals themselves in the dense network. Switch to letting the animals come out on their own in these cases:
- Remove the plant from the flower pot
- shake off earth
- Completely submerge root ball in bucket of water
- Leave for about 5 minutes to allow animals that are deep in the root system to escape
- Fish off and discard any floating grubs
Nematodes vs Maggots
Instead of replacing the soil completely, there are also other, far more “sensitive” ways of fighting the caterpillars. Special beneficial insects are able to kill the grubs in the soil. The most widespread beneficial insects are nematodes. The so-called threadworms are able to carry bacteria that are deadly for the larvae. If the worms, also known as elks, are released into the ground, the grub takes them in with the food and dies.
Nematodes are available in well-stocked garden shops. And it is also very easy to use. As a rule, the beneficial insects are offered in solid containers, for example made of clay. These can be stuck into the ground and are dissolved by the moisture in the ground. Once the worms are released, they spread into the soil and are inevitably ingested by the larvae.
take
The active ingredients of the neem tree (Azadirachta indica) are rather unknown. These prove to be another type of natural pest control against a variety of insects and eventually larvae such as the grub. Neem products are usually offered as a powder and can be easily incorporated into the potting soil. There, after being ingested by the beetle larvae, they stop development. The animal no longer changes to the next stage of development. In connection with an inhibition of the appetite, the animals do not die immediately, but inevitably die off in the long run.
The decoy trap
Young grubs can be lured out of their respective flower pots in spring in a different way:
- Fill the bucket with horse manure to about 10 centimeters below the rim
- Bury the bucket in the ground up to the top edge
- Fill the remaining bucket volume with soil
- Arrange potted plants around the bucket
The young larvae are attracted by the smell of the manure and migrate out of the pots into the manure bucket. Because of the smell and the general hygienic conditions, horse manure should not be used in the apartment. However, if the decoy remains in place until autumn, the flower pots can be brought into the house in autumn with a high degree of certainty free of maggots. Because all newly hatched animals are attracted again and leave the place where the eggs were laid.
