White Grubs

• White grubs are the larvae stage of scarab beetles. These beetles lay their eggs in the spring and summer on lawns that are healthy and have moist soil. Grubs hatch and eat the grass' root systems. Pests that hatch in the spring typically eat grass roots for a short period before they mature. It is difficult to notice their damage, because the grass is still coming out of dormancy and is actively growing.
  
  

Damage

• Gardeners may notice brown patches of dead turf grass. The size of these dead areas depends on the severity of the grub problem. When white grub problems are severe, gardeners are able to to roll back their turf like a rug. A spring grub treatment may seem ideal once you notice the damage. However, beetles will continue to lay eggs at the end of the summer; therefore, you will just have to treat again. Also, white grubs hatched in the spring are harder to control and resistant to pesticides, according to Cornell University.
  
  

Testing

• Conduct a white grub test on your lawn in the summer to find out the severity of your pest problem. Dig up a 1-square-foot area of turf in the yard. Sift through the dirt for white grubs. Grubs typically look white and are C-shaped. If you find more than 10 grubs in the 11square1foot area, treat the lawn with a pesticide. Lawns that have fewer than 10 in 1 square foot do not require treatment.
  
  

Treatment

• Rake up dead grass and thatch on the lawn, so that the pesticide can sink into the soil. You can rent a power dethatcher to remove thatch layers over 1/2 inch thick. Apply a pesticide that contains diazinon, bendiocarb, imidacloprid or halofenozide, according to the University of Illinois. Water the lawn with 1/4 to 1/2 inch of water after applying the pesticide. Watering the lawn allows the pesticide to leach into the root zone of your grass.