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The cockchafer larva is one of the most dangerous pests in the garden, as it mainly feeds on plant roots. If you fear and want to confirm a grub infestation, you need to recognize them.
In a nutshell
- Cockchafer larvae can be clearly recognized by their size
- they have 3 pairs of legs and powerful mouth limbs
- most commonly come in white, cream, or gray
- do not stay outside of the earth
appearance
The cockchafer larvae can be easily recognized in your own garden because of their appearance. The larvae of the genus Melolontha are known under the term grubs, which already gives an indication of their appearance. These are quite thick caterpillars that can reach lengths of five to seven centimetres, making them a popular snack for animals such as birds and hedgehogs. To recognize the cockchafer larva, take a look at the following list of appearances:
Cockchafer grubs. Source: Botaurus, Melolontha-melolontha-20-VII-2007, crop from Plantopedia, CC0 1.0
- Body color: white, light gray, cream, orange to brownish, less often black
- individual segments provided with dark dots on both sides
- dark abdomen
- Color of the head: brown
- Shape: curved, cylindrical
- Number of pairs of legs: 3
- legs bent
- Pairs of legs are in front behind the head
- Mouthparts recognizable
Notice: Cockchafer larvae look very similar to the grubs of the protected rose chafer (Cetonia aurata) and rhinoceros beetle (Oryctes nasicornis). They may not be caught, killed or disturbed in any other way.
Other features
Not only the appearance of the may beetle larvae provides information about them. To be able to distinguish them even more easily from other beetle species, you should know certain behavior patterns. These help identify the larvae once you've spotted them. Since the cockchafer larva feeds on roots, it can only be found in the soil. They stay along the roots to feed on them over a long period of time. It doesn't matter whether it's an outdoor vegetable patch or a flower pot, grubs can be found almost anywhere. The following points will provide you with more information about the larvae:
grub of the rose chafer. Source: Fritz Geller-Grimm, Scara fg03, cut from Plantopedia, CC BY-SA 3.0
- move meandering
- always on the side
- sensitive to daylight
- prefer soil with little clay
- preferred depth: about 100 cm
- often curl up outside of the ground
- never stay in compost or garbage
Tip: During longer dry periods, the cockchafer larvae dig deeper and deeper into the ground until they have found a moist layer of soil. So wait until it has rained to dig up the larvae.
frequently asked Questions
How can cockchafer and rose beetle larvae be distinguished?In appearance, rose beetle larvae do not really differ from cockchafer grubs. The features of the protected larvae can only be discovered on closer inspection, including the somewhat thicker posterior. They are easier to distinguish based on where they are. Rose beetle larvae are mainly found in compost or in rotting wood and are beneficial insects that contribute to better decomposition of the compost.
How can they be distinguished from rhinoceros beetle larvae?Since rhinoceros beetles, like rose beetles, are protected in Germany, you should never injure or even kill the animals. You can recognize rhinoceros beetle larvae mainly by their size, because they grow to be seven to twelve centimeters tall. Otherwise they resemble the cockchafer larvae down to the eye. Pay attention to the color, because the dark areas and spots on the side are not as light as in cockchafer larvae.
How long do cockchafer larvae take to pupate?It takes four to five years for the grubs to pupate. The larvae eat over this time until they reach a certain size. For this reason there is a greater infestation by the animals in some years and there are significantly more cockchafers on the move.
How can grubs be effectively combated?Good prevention with regularly scarified beds and lawns, as well as a lack of garden lighting at night, helps against May beetle larvae. This makes it difficult for the adult cockchafer to mate and lay eggs. Larvae that have already hatched are attacked by predators such as birds, shrews or moles. Nematodes are also an effective measure against grubs.