Grub Control

Grubs can often be present with or without any signs of damage to your lawn. The first key step to gaining control if you notice damage or find grubs is to start with a curative application, following up with preventative applications to help reduce the chances of the grub damage reoccurring. Pheromone traps (Japanese beetle traps or bug bags) are not recommended as they often attract more beetles than they trap, and often cause a more severe problem. The strong sent of the pheromones can attract beetles from sever thousand feet away.

Monitoring for Grubs

Monitoring for grubs is important to determine if damage to grass may occur at a later time or if grubs contributed to the current damage being experienced. Grubs are often a problem on south facing slopes and grassy areas that get full sun exposure. 


Look for adult grubs, which are in the form of a beetle, June through early August. Japanese beetles are often found eating on the leaves of many trees and shrubs, while oriental beetles can be found resting on the plants. Where adults are found, females are often laying their eggs nearby in a lawn area.


White grubs can be found April through May and mid-August through mid-October. To inspect a suspected problem area, use a pointed shovel to cut three sides of a square in the turf, 6 to 12 inches in length on each side and about 3 inches deep. Peel back the strip of turf and loosen the soil from the root system. Five to ten grubs per square foot is a tolerable threshold, higher levels require action to be taken. If conditions are drier than normal a lower threshold may be used as damage is more serious during dry periods. Be sure to inspect several locations as they may be present in one location, but not others.

Controlling Grubs

Curative applications, such as Bayer 24 Hour Grub Control with Dylox, should be made when the grubs are actively feeding, in the early spring and fall. Watering with approximately ½ an inch of water before and after application will help improve effectiveness. The pre-application watering will help bring grubs closer to the surface. Post-application watering will help bring the product to the grubs. Curative applications are only necessary when there is a known grub problem; therefore checking for grubs is important.


Preventative applications, such as Bayer Season Long Grub Control with Merit, should be made June 1 through July 15 for best results. Preventative applications are important because they help in reducing damage that may occur to the lawn. An advantage with preventative applications is they are often more environmentally friendly than curative applications. 


Stop by The Garden Barn for more information on grub control and how to grow a great lawn.