There are several types of Chafer Beetle that cause damage to plant leaves. And, of course there is the cockchafer Beetle grub, which causes severe root damage. All Chafers are members of the Coleoptera family, and known by various names - 'Maybug' being one.
They fly at night, and have often been the cause of concern when flying into windows - attracted by the light.
The Cockchafer shown in the image can grow to a size of 4cms. Some of the smaller chafer beetles to just 1cm. The cock Chafer beetle causes damage to leaves - biting out irregular shaped holes in foliage - sometimes the edges - sometimes holes in the leaf itself.
The Chafer Beetle – unlike its offspring – are not considered too much of a pest in the UK – unless it happens to you of course!
Perhaps the most damage by Chafer Beetle adults is caused to grape vine foliage, where they literally skeletonise the leaf, leaving only the central and lateral veins. This if not checked will lead to huge fruit loss and even death of the vine in some instances. This type of damage is rarely seen on UK plants at the moment but, with changing weather patterns, all things are possible. Severe winters seem not to affect the population.
The beetle damage will be a relatively short span of time, for the life cycle of the Chafer Beetle, includes the adult form living for just a few weeks. They emerge from the soil – where the grub has been feeding on roots for most of the year – in mid June depending upon seasonal fluctuations. They then mate, lay their eggs in the ground and die off.
Chafer beetle adults only attack the foliage of a plant – it is their larva that does the root damage. It has a varied diet, and many trees, shrubs and hardy perennials are targets for the different types of Chafer Beetle.
Cockchafer Beetles sometimes eat into new rosebuds, causing them either not to open, or if open, then one sided blooms are the result. It seems that they are prepared to forgo the foliage feat in favour of the succulent buds. In this instance they are rarely sighted, so not recognised as the culprit either!
The beetle stage of growth is relatively harmless compared to the damage caused by the Chafer Beetle Grub. The grub lives in the soil for up to three years - fattening itself up on plentiful supplies of plant roots and tubers.
Most Contact Insecticides will kill the adult beetle, but firstly be certain that it is enough of a pest to warrant the spray!