How to Fix Your Lawn for Grubs

Grubs cause a patchy-looking lawn.

Grubs are Japanese beetle larvae. The adult has a shiny-green, metallic-looking shell. Adult beetles feed on the leaves in the home garden and lawn. The grubs live below the soil surface, eating grass roots. The adult beetle emerges the last week of June or early July. Grub control is done in the summer before the larvae’s shells harden and insecticides do not work. The lawn recovers once the grubs are under control.

Things You'll Need

• Spade
• Insecticide
• Garden sprayer
• Hose

Instructions

1. Cut a 6-by-6-inch sample of turf from the lawn using a spade. Cut through the soil’s surface with the spade, and then slide the spade’s blade under the soil. Lift up the soil sample and inspect it for grubs. Control is necessary if there are more than three grubs in the sample.

2. Take a grub from the sample and send it to your local university extension for identification. The university will tell you what insecticide is most effective.

3. Mix the insecticide recommended by the university according to the instructions on the side of the fertilizer container. All insecticides are mixed differently.

4. Place the insecticide in a garden sprayer. Pump the garden sprayer to increase the pressure inside the sprayer.

5. Spray the grass in even movements, slightly overlapping each spray to cover the lawn.

6. Water the lawn with a weak stream of water to soak the insecticide into the soil.

References

• University of Rhode Island; White Grub Control; Steven R. Alm, et al.; 2002
• Penn State University; White Grubs in Home Lawns
• The Ohio State University; Control of Japanese Beetle Adults and Grubs in Home Lawns; David J. Shetlar