Cockchafers or 'Maybugs' and other Chafers

On warm evenings in early summer, you might be startled by a loud clatter
on a lighted window - take a torch and investigate - there is a good chance
it will be a Cockchafer or 'Maybug' attracted by the house lights . . . . . .

Cockchafer (Melolontha melolontha) - adult beetle 25-35 mm long  

Chafers are beetles (order Coleoptera), and belong to the same family as the scarab or dung beetles (Scarabaeidae). The most familiar of our chafers is the Cockchafer or 'Maybug' (Melolontha melolontha) - the adult beetle (shown above) is a night-flier and often comes crashing into lighted windows on warm evenings in early summer. Its large size (25-35 mm long) and buzzing flight make it a little frightening, but the beetle is quite harmless and will not bite or sting.

Adult chafers eat the leaves and flowers of many deciduous trees, shrubs and other plants, but rarely cause any serious damage in the UK. However, their fat, white grubs (reaching 40-45 mm long when full grown) live in the soil and feed on plant roots, especially those of grasses and cereals, and are occasional pests in pastures, nurseries, gardens, and in grassy amenity areas like golf-courses. The injury to grassland and lawns results in poorly growing patches that quickly turn brown in dry weather; the grubs can be found immediately below the surface, usually lying in a characteristic comma-like position (as illustrated below). The grubs sometimes attack vegetables and other garden plants, e.g. lettuce, rasberry, strawberry and young ornamental trees. Injury to the roots and rootstock causes small saplings and tender tap-rooted plants like lettuce, to wilt suddenly or to show stunted growth and a tendancy to shed leaves prematurely. Plants growing in rows are usually attacked in succession as the grubs move along from one plant to the next. Chafer grubs feed below ground for 3-4 years before changing into adult beetles.

Cockchafer larva (or 'white grub')

In Britain and other parts of Europe, several smaller species of chafer beetles, as well as the large Cockchafer, can be serious garden and agricultural pests:

(1) Welsh chafer (Hoplia philanthus), 8-9 mm long; (2) Summer chafer (Amphimallon solstitialis), 14-18 mm long; (3) Brown chafer (Serica brunnea), 8-10 mm long; (4) Garden chafer (Phyllopertha horticola), 9-11 mm long; (5) Rose chafer (Cetonia aurata), 14-20 mm long.

Adults of all these chafers feed on leaves, buds and flowers of deciduous trees and shrubs. Their grubs (except those of the Rose chafer) eat plant roots and often cause damage to ornamentals, edible crops, pastures and lawn grass. The grubs of all species resemble those of the Cockchafer (see above).

Damage by chafer grubs can be reduced by cultural techniques, and by the use of chemical and/or biological control methods if available. In small gardens it is often sufficient to simply remove and kill the grubs by hand when they are found. Thorough cultivation and good weed control of flower borders and vegetable plots will generally ensure that plant losses are minimal. Infested lawns may benefit from heavy rolling in late spring to kill pupae and emerging adults, and also from adequate watering and feeding to encourage growth of the grass. When severe damage is caused, re-seeding of bare patches in spring may be necessary. It is difficult to keep up to date with the range of chemical and biological pesticides available to the general public for controlling household and garden pests. Seek advice from a good pesticide stockist or garden centre for currently approved insecticide products.

REMEMBER TO USE INSECTICIDES SAFELY AND FOLLOW ALL THE INSTRUCTIONS ON THE PRODUCT LABEL