The Chafer grub causes a lot of root damage – mainly to lawns. However Chafer Beetle grubs can also cause limited damage in borders and the vegetable plot. In the borders, they are happy to eat the roots of younger plants, and the damage can often be mistaken for the similar symptoms of vine weevil beetle. The foliage of young plants wilts, quickly followed by the death of the rootless plant!
In the vegetable garden it will feed upon roots and also gnaw into tubers and bulbs. Potatoes in particular can be affected. In this instance there will be no visible above-ground symptoms until the crop is harvested.
A tell tale sign that Chafer Grubs are in attendance, is the presence of larger birds – crows in particular – pecking away at the soil. In rural areas, foxes sometimes cause problems by digging deep especially in the winter months, in search of the nutritious grub!
Image shows a well advanced Chafer grub in the spring.
Chafer Grubs damage roots and underground stems of many plants during the winter and spring months as they overwinter in the soil – moving deeper down to avoid the freezing soil – but still feeding on roots..
It is not a serious pest of established plants.
Those found in the autumn will not have such advanced legs and will normally be a light cream colour.
They are not a serious pest in any part of the garden other than the lawn - where they can do considerable damage. They can however, do considerable damage to newly planted annuals and perennials. Mature plants are rarely killed when in active growth.
The best control of chafer grubs is to destroy them as they are bought to the surface by digging. Together with this, Starlings like a feast of Chafer grubs, so do not deter them from digging away in the border.
If wilted plants are dug up and it is found that the root system has been attacked, then it will be either Chafer grub or Vine weevil beetles that will probably be the problem.
Nemasys - a biological control based upon nematodes can be used to control Chafer Grubs in the Lawn. Other parts of the garden rarely need anything other than localised search and destroy tactics.
There can be incidental damage caused by the fact that you have Chafer grubs. If you live in an area where there is a large badger or fox population, they love to dig the grubs out for a tasty meal. As such, the damage that foxes cause by digging, is often worse than the actual damage caused by the Chafer Grub!