Lawn Grubs: How to Apply Nematodes [Video] Posted on June 10, 2019, Edited September 16, 2019 by Chris Heckel For any lawn enthusiast, the white grub is public enemy #1! The brown patches the white grub leaves on your lawn aren’t just ugly, they are an eyesore. Fight grubs naturally with beneficial nematodes, naturally occurring microscopic worms that prey on grubs. An enemy of my enemy is my friend! For more tips on how to keep your lawn lush and beautiful visit the Johnston’s Greenhouse Garden Center and speak to a member of our team.