Fighting grubs with nematodes – what you need to pay attention to when using them. There are over 20,000 species of nematode, some of which are also pests that can attack plants, especially roots.
Nematodes only become active at soil temperatures above 12 to 14 degrees Celsius, so you should wait for these temperatures in spring. April to September is a good time for this, as that is when the larvae hatch. Most infected grubs die within two weeks. In order to permanently get rid of the grubs, it is sometimes necessary to use them for two years.