How to Spray for Grubs in the Lawn
- 1). Cut a 6-by-6-inch hole in the grass and examine the first three inches of soil underneath. The University of Rhode Island Horticulture program says this procedure is best performed in early August, when most of the eggs laid in the summer have hatched into larvae. Repeat several times throughout the yard.
- 2). Count the number of grubs found in the uprooted areas. The Purdue University Extension Garden Tips site suggests considering treatment options in the fall if more than five grubs are found per square foot.
- 3). Purchase a curative grub killer. Curative grub killers come in a spray or granular form.
- 4). Spray the curative grub killer on the lawn, covering the entire lawn but focusing on patchy, brown areas. Granular insecticide should be applied with some variety of seed spreader. The Western Massachusetts Master Gardener's Association suggests applying the grub killer during cool weather of less than 80 degrees and low humidity, but when rain is predicted.
- 5). Water the grub killer into the grass if no rain is forecast for the near future.
- 6). Purchase a preventive grub control the following July.
- 7). Spray the preventive grub killer on the lawn. Granular insecticide should be applied with some variety of seed spreader. The University of Illinois Homeowner's Column says to apply preventive grub killer in July regardless of any directions on the bag, as this is the time of year that older grubs are largest and new eggs are hatching.
- 8). Water the lawn to work the preventive grub killer into the soil.
Source...