If potted plants no longer want to grow properly and look a bit miserable even without any detectable above-ground pest infestation, underground culprits are usually at work. If you dig something in the substrate, you will often find them in the form of maggot-looking lads.
Cockchafer grubs sometimes appear in flower pots and should be moved carefully
What kind of maggots could that be?
There are countless species of insects that lay their eggs in the ground, where the larvae can then feed and develop themselves after hatching. We are now concentrating our attention on species that can severely damage your potted plants - because you usually do not have to worry about the rest.
If you come across large, white, worm-like animals in the substrate while looking for the cause of dying pot plants, they are most likely not maggots, but larvae of certain beetle species. Maggots form a special group within the insect larvae: they are characterized by a very poorly developed, naked body appearance without any limbs, and they do not even have a head capsule.
Are the dubious inhabitants of your flower pot large, fleshy, whitish with a darker front (and rear) part and possibly with 3 pairs of sternums? Then you are probably dealing with the following malware:
- grubs
- Vine weevil larvae
grubs
The larvae of the beetle superfamily Scarabaeoidea are called grubs. Species that are relevant in our latitudes are mainly May, June and garden chafers. Their larvae feed on the roots of living plants and can damage lawns, bedding plants and even potted plants.
Vine weevil larvae
The larvae of vine weevils do not belong to the grubs, but they do not belong to the maggots either. The vine weevil, which belongs to the weevil family, is a widespread and therefore feared pest in agriculture and in private garden culture. Unfortunately, it also eats the roots of living plants in addition to dead plant material.
What to do?
A potted plant infested with grubs or vine weevil larvae should first be removed from the planter and the soil searched for the pests. Search as thoroughly as possible and collect the little guys. In the case of severe infestation and plants with dense roots, you can use the water jet of your garden hose to help and if necessary rinse the roots completely free.
If the root system is very difficult because it is too narrow, you can also use predatory nematodes. The parasitic nematodes colonize grubs and vine weevil larvae and thereby kill them.