Pesky grubs cause extensive damage to lawns and gardens. The typical signs of a grub infestation is the wilting of grass in patches and sod that is loose and rootless. In some cases, there might also be increased feeding activity of birds. Damage is most extensive in fall or during dry periods as the plants have little resources to recover. Getting rid of grubs permanently takes a two-pronged approach; you must prevent as many grubs from settling and breeding as possible, and you must continue to kill any grubs that remain.
Inoculate the affected soil with milky spore bacteria. This is done by following the directions on the bacteria cards or powder. Usually it involves embedding the bacterial colonies into the soil throughout the entire garden or lawn. A churning and watering of the soil is then required. One proper inoculation allows the bacteria to remain active in the soil for years. This bacteria causes a long-term disease in the grubs known as milky spore disease. It takes months for this disease to kill the grubs, and is usually reserved as a preventative measure as it kills grub larva much quicker.
Introduce nematode worm larvae to the affected soil. Churn the soil and water to allow the worms to properly develop. The worm larvae grows and begins to eat the grubs within one week. These worms die quickly and you must release larvae every three to six weeks to maintain a grub fighting population. The worm larvae can be stored in the refrigerator for up to two months.
Continue application of both products until all adult grubs have been killed. This is evident in the sustained disappearance of signs of a grub infestation. Reintroduce the milky spore bacteria annually to prevent another infestation.