Use beneficial nematodes as organic grub control in late summer

What to Do

Purchase Heterorhabditis bacteriophora nematodes from a reputable supplier. Apply in late July to early September when grubs are small and soil temperature is above 50°F. Water the lawn thoroughly before and after application. Apply at dusk or on an overcast day.

Why It Works

These microscopic worms seek out grubs in the soil, enter their bodies, and release bacteria that kill the grub within 24-48 hours. MSU Extension notes they can persist for several years after application, providing ongoing control. They are completely safe for humans, pets, and beneficial insects.

Tips

• Nematodes are living organisms — buy from a refrigerated source and apply immediately.
• They are killed within minutes by direct sunlight, so evening application is essential.
• Effectiveness is lower than chemical options but they provide a long-term biological control.
• Keep the soil moist for 2 weeks after application while nematodes establish.