White grubs, cockchafers

White grubs are insects of the order Coleoptera, whose larvae feed on the roots of plants, causing significant damage in gardens and green spaces. Here is some information on their description and biology:

Description: Adults, also called beetles, are brown to black beetles, 2-3 cm in length, with short, thick antennae and hard elytra that protect the wings. The larvae are off-white in color, have a curved shape and measure 2 to 4 cm in length.

Biology: Adults emerge from the ground in the spring, usually May or June, and feed on leaves and flowers for a few weeks before laying their eggs in the soil. The eggs hatch into larvae which feed on plant roots for two to three years, passing through several stages of development. At the end of their life cycle, the larvae turn into nymphs and finally into adults, which emerge from the ground to mate and lay eggs again.

White grubs are considered pests because their larvae cause extensive damage to plant roots, which can lead to weakening, discoloration and even death of plants. Symptoms include wilting plants, yellowing leaves, eaten roots and dead spots in lawns.

There are several methods to control white grubs, including the use of entomopathogenic nematodes, crop rotation and the promotion of biodiversity in gardens to encourage the presence of natural predators.