Grubs feast on grass roots and are the larvae of beetles like Japanese beetles, June beetles, or European chafers. Adult female beetles lay their eggs in grass in mid-to-late summer and the larvae do the most damage in late summer to early fall. They burrow deeper and become dormant over winter. As the soil warms in spring, they resurface and feed again. They then cocoon and become adult beetles. The best time to treat your lawn for grubs is in the spring or fall when they are active and feeding.
Earth-friendly beneficial nematodes seek out and kill grubs and other soil-inhabiting insects. “The microscopic worms come on a sponge (invisible to naked eye) that you soak in water, put in a sprayer and spray your dirt or lawn. They will multiply over time as they continue to kill grubs. Also, they have nematodes that seek and destroy flea larvae too.” In Northern climates, the best time of year to apply nematodes is in the spring or fall when the grubs are active in the soil. In warmer climates, nematodes can be effective all year. Avoid fertilizer application within 2 weeks of applying nematodes, as the high nitrogen content can be harmful to them. Check labels on pesticides, some are safe for use simultaneously and others are not.