Larvae of the cockchafer; the most common species in Central Europe is the field cockchafer (Melolontha melolontha) This species appeared in large numbers for the last time in the 1950s. From the end of the 1990s onwards, there was again a massive occurrence in Switzerland, South Tyrol and the German Kraichgau (Baden wine-growing region), which required control measures. The field cockchafer generally undergoes a three-year development and flies in every fourth year. In the first year, after mating from the end of April to the beginning of June, the eggs are laid at a depth of 10 to 25 centimetres. After about six weeks, the three-stage larvae (Engerlings) hatch and feed on the roots of vines until autumn.