As a native coniferous tree, the yew is very well adapted to our conditions and copes very well with pests, fungal infestation and diseases. Occasionally a pest infestation can occur, especially in an unfavorable location. How to identify and combat yew tree pests.
What pests occur on yew trees and how do you combat them?
Pests such as scale insects, lice, black weevils and gall wasps can occur in yew trees. Biological agents such as parasitic wasps, lacewings and nematodes as well as removing infected branches and ant trails are suitable for combating.
What pests occur on yew trees?
- Scale insects
- Lice
- Black Weevil
- Gall wasps
Basically it can be said that a he althy tree that is well cared for can easily cope with a pest infestation on its own. Only if the yew tree is in an unfavorable location or does not receive sufficient care can the unwanted guests cause damage.
Identifying and fighting scale insects
Scale insects cannot be seen with the naked eye. If the needles turn yellow or brown or fall off, you should always check the yew for scale insect infestation. If there are ant trails on the tree, an infestation is likely.
Only biological control measures such as the use of parasitic wasps and removing the ant trails help against scale insects. Severely infested branches should simply be cut and burned if possible.
Treatment for lice infestation
You can see lice with the naked eye. Lacewings and ladybirds are suitable biological controls. Insecticides can also be used here.
Fighting black weevils
Black weevils are found in the ground and eat the needles at night. These pests are very difficult to control. If the infestation is severe, we recommend using nematodes (€43.00 on Amazon), which you can purchase from specialist retailers. These nematodes eat the larvae of the black weevil.
How to fight gall wasps
If the needles become discolored and deformed, gall wasps may be responsible. Here it is advisable to radically cut off the affected branches of the yew tree. The use of biological agents such as parasitic wasps is only advisable if the infestation is not too severe.
You should not compost branches that are infested with gall wasps, but rather dispose of them with household waste or burn them.
When cutting, make sure that neither needles nor other plant parts get on the bare skin. The poisonous plant sap can cause inflammatory reactions.
Tip
Diseases almost never occur on yew trees. If the yew tree looks sick, loses needles or is generally in poor condition, it is usually due to the wrong location or the water supply.