Determine May beetle larva: picture with grub

Cockchafer larvae are among the garden pests. However, since there are also beneficial insects among the scarab beetle larvae, you should identify the larvae before you initiate countermeasures.

Maikäfer (Melolontha)

The genus Melolontha belongs to the family of scarab beetles (Scarabaeidae). In Central Europe, the cockchafer (Melolontha melolontha) is the most common species. The cockchafer (Melonlontha hippocastani) occurs in some regions of Germany. The rare Melonlontha pectoralis is only spotted every now and then in south-west Germany.

Engerling

The term Engerling is derived from Middle or Old High German and means “little worm”, “made”. Today the term grub is used for larvae of the scarab beetle, which, in addition to the may beetle, are well-known beetles such as

  • Junikäfer (Amphimallon solstitiale)
  • garden beetle (Phyllopertha horticola),
  • Common rose chafer (Cetonia aurata) or
  • Nashornkäfer (Oryctes nasicornis)

belong.

Determine the cockchafer larva

Look

  • becomes five to seven centimeters long
  • C-shaped curved body
  • front and rear (continuously) the same thickness
  • whitish to slightly yellowish
  • brown head with powerful jaws (mandibles), clearly visible
  • three pairs of legs at the head end
  • strong, long legs with clearly visible joint creases

habitat

  • live underground

nutrition

  • first humus
  • Living weed and grass roots (yellowed areas in the lawn)
  • later also from tree roots
Note: The term may beetle refers to the main flight times of the beetle (May and June) and not to the larvae.

Risk of confusion with harmful grubs

In addition to the larvae of cockchafers, the grubs of June and garden beetles are also among the pests. It is essential to distinguish them from those of the rose beetle and rhinoceros beetle, since the latter are protected beneficial insects.

A difference between the larvae of the pests is hardly visible to the layperson. Only the size can serve as an indication, because the grubs of June and garden chafers are smaller:

  • June beetle: up to three centimeters, larger specimens are possible
  • Garden chafer: up to two centimeters
Note: However, the orientation based on size is not reliable, as it can also be younger stages of May beetle larvae.

Risk of confusion with useful grubs

A confusion with the larvae of rose beetles and rhinoceros beetles is actually not possible, since these grubs feed on dead plants and wood residues, i.e. they inhabit a completely different habitat than the cockchafer larvae. These grubs can be found, for example, in the compost heap.

The larva of the rhinoceros beetle (Orystes nasicornis) is significantly larger than that of the cockchafer.

There are also characteristics that are useful for determining:

  • significantly thicker rear than front
  • Rhinoceros beetle larva: up to ten centimeters long
  • Rose beetle larva: if disturbed, crawls away lying on its back

Kira Bellingham

I'm a homes writer and editor with more than 20 years' experience in publishing. I have worked across many titles, including Ideal Home and, of course, Homes & Gardens. My day job is as Chief Group Sub Editor across the homes and interiors titles in the group. This has given me broad experience in interiors advice on just about every subject. I'm obsessed with interiors and delighted to be part of the Homes & Gardens team.

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