Earlier this Spring a friend of mine told me how grubs (the larva of Japanese Beetles) had killed some patches of their front lawn. She's never even heard of grubs (neither had I) and was sad that she had to learn how to take care of them the hard way. The local lawn and garden store advised that she put down some grub prevention stuff (pesticide) in the fall and then she wouldn't have to worry about it in the summer. So, rather than buy a grub killer, of course I wanted to see if there was something I could make instead.
Here's what I found:
Someone asked a similar question here. The basic answer is that grubs aren't always that bad, so long as there aren't so many that nature can't take care of them. Birds love to eat grubs and can usually keep them down. But, when there is a problem with grubs (some types of grasses have more of a problem than others), the expert advised mixing detergent with water and spraying it on the grass. The grubs are supposed to come to the surface. The expert says that the detergent actually isn't bad for the grass either. Elsewhere, I read to sprinkle the detergent on the grass and then soak the area thoroughly with water.
From what I've read, I think rather than putting pesticide all over my lawn in the effort to prevent grubs, I'll just take my chances and treat any trouble spots with detergent and water.