Combat vine weevil on yew

What damage does the vine weevil cause to yew trees?

The thick larvae of the vine weevil mainly eat the roots of infested yew trees (as well as other host plants such as rhododendrons or cherry laurel). They can root eaten away to such an extent that the affected tree can no longer find a footing in the ground and can fall over. You can recognize an infestation, for example, by the fact that the yew grows despite an adequate water supply dry up threatens.

Another indication of a possible infestation can also be nibbled needles, which are caused by the adult weevil to be damaged. The bay feeding is a specific reference to the pest!

How do you know the vine weevil and its larvae?

The vine weevil is an approx. a centimeter long, greyish colored beetle from the weevil family. The pest is nocturnal and hides during the day, so it is very rarely seen.

Rather, one discovers the cream-colored larvae, which live underground in humus-rich, loose soil and are found, for example, when gardening. By the way, not only are yews planted in the garden, but also in pots Cultivated plants endangered - the latter in particular, since the often nutrient-rich plant substrate offers the best conditions for the beetle and its offspring.

How to successfully combat the pest?

Slight feeding damage to the yew needles can generally be tolerated. However, you cannot ignore the larvae that destroy the root system. The best way to combat this is with roundworms (nematodes), which you can purchase in specialist shops. The microscopically tiny animals are spread out with a watering can at a soil temperature of more than 12 °C and kill the beetle larvae. A roundworm of the species is particularly suitable for combating it

• Heterorhabditis bacteriophora
• Steinernema Kraussei
• Steinernema carpocapsae

Fighting pests with nematodes makes it possible to do without insecticides and other pesticides. Instead, this method is gentle on beneficial organisms, people and the environment.

Can infested yew trees regenerate?

In principle, infested yew trees can regenerate. However, you may find the affected tree cut back heavily must - in the case of serious root damage this is even incessant. Eventually, the remaining roots can no longer fully support the tree.

It also makes sense to use growth-promoting agents to accelerate root growth. You can water the yew with willow water or the boiling water from potatoes (cooled down, of course!). Yeast water (100 grams of yeast dissolved in one liter of water) also works well.