Grub worms can be killed by both natural methods and by purchasing grub worm treatments. Natural methods include applying milky spores or neem oil to the affected area or adding nematodes to the soil. Purchased treatments include Dylox, Merit and Mach-2.
Grub worms are the larvae of various beetles, such as the Japanese beetle and masked chafer. They form cocoons in June and emerge in August as full grown beetles. Grub worms not only damage the lawn but invite other unwelcome wildlife to the area. Late summer to early fall is the time most damage occurs and the best time for treatment. Grub worms cut off grass plant roots, making the grass more susceptible to lack of rain. Visible brown patches are the first sign of grub worm infestation.
Grub worms are smaller and closer to the surface during the fall. This is when they do most of their damage and is also the best time to apply treatment. Dylox is the most effective insecticide for treatment during this period, killing the pests before they can lay their eggs and addressing the problem of any hatchlings.
Natural methods work both as repellents and as treatments. Natural treatments are environmentally safe and generally less expensive than purchased pesticides.