When replanting or repotting flower boxes, an unpleasant surprise sometimes awaits: grubs basking comfortably in the ground! It does not help here - the root-eating pests must be taken care of. We'll show you how.
Engraved grubs can literally be flushed out of the flower box
How do grubs get into flower boxes?
Every 2-4 years there is an imago phase in the cycle of May and June beetles, which is quite long for insects. The adult beetles, which only live for a few weeks to prepare for the next generation, are called imagos in zoological terms. During these weeks they have the following tasks:
- Wolf down
- Mate
- laying eggs
The fulfillment of the first task is still all too painfully known to earlier generations of people: Up until the 1950s, there were regular plagues of cockchafers that defoliated entire forests. After mating, the males die again, the females lay the eggs before they die. And for this they look for places that promise the hatching larvae a good source of food - i.e. wherever plants with tender, nutritious roots grow. Flower boxes (€16.99) planted with flowers, herbs or vegetables can also be selected.
How to remove the grubs?
Mechanical: collecting or rinsing
The grubs should initially be removed purely mechanically - preferably manually. If possible, remove the entire planting from the box by tipping it on its side and carefully loosening the contents. If the plants are already established and have a developed root system, you can search for the pests relatively briskly. Rinsing the root system with a water jet can also help with sorting.
Strategic: immersion bath or nematodes
With young plants that are still tender, things are a bit more difficult. Because they cannot really be removed from the box without damage and examined for grubs on the still young roots. An immersion bath can help here, completely soaking the earth and thereby driving the grubs to the surface. There they can be collected. The use of predatory nematodes is also recommended here, preferably in addition.
Notice!
If you have other planters on the balcony, be sure to check them for grub infestation as well.
prevention
It is also advisable to stretch insect protection nets over the flower boxes or to plant garlic as a deterrent during the flight times of May and June beetles. This prevents the beetles from laying eggs.