There are several types of white grubs in lawns. The most common ones are the European chafer and the Japanese beetle which are considered as root-feeding pest insects. Depending on the type of white grub and temperature, egg laying occurs from the end of May to July. Hatched eggs give larvae that remain in the soil and feed on lawn roots then hibernate in the soil. In the following spring, the larvae become pupae, then adults to mate and lay eggs. Some types of white grubs have one generation per year. Other types have more than one generation and some other types whose generation lasts more than a year. You must identify the type of white grubs in your lawn to determine the treatment.