Why Is Grub Preventative Important?

A grub preventative application in late May through early June can be one of the best tools for preventing grub infestations. The threshold for grub populations is 10-12 grubs per square foot. Turf cannot recover from infestations nearing the threshold. A preventative application is all about the timing of the treatment. Applications only work if applied prior to egg hatch. Because several varieties of beetles lay their eggs in lawns, knowing which beetles hatch larvae that will damage turf is vitally important. Below are the most common beetles (grub worm larvae) that cause turf damage.

Masked chafers usually lay eggs first. They are the copper or bronze colored beetles seen mostly at night where they are attracted to lighting. Japanese beetles are metallic green with coppery-brown wing covers, which do not quite cover the tip of the abdomen. Adults damage the leaves of trees and shrubs while the larvae damage grass roots. Preventing Japanese beetles and their larvae is good for the whole landscape. The Green June beetle is a larger beetle, and their larvae are larger than the previously mentioned adult beetles. However, their cycle can be in the range of 1-4 years from egg hatch, to larvae, to adult beetle; whereas, the aforementioned beetles have annual life cycles.

The prevention of these larvae prevents the damage that can occur when populations near the threshold. Damage done from infestations can take several months to recover. Since most of the damage is done in late Summer or early Fall, turf injury is not noticed until Spring when dormant grasses start to regrow.

Secondary problems can also occur when grubs are left unchecked. Skunks, moles, armadillos, and other animals feed on the grubworms in the landscape. Tunneling, digging, and feeding on these grubs can lead to further damage in home lawns. Damage can continue to occur into the following Spring when the larvae return near the surface to feed prior to turning into adult beetles again.

Have you ever heard “An ounce of prevention is worth a pound of cure”? This is very true when it comes to grubworm infestations. TDI Lawn & Pest recommends anyone whose lawn has had an active grub infestation in past years to consider getting a preventative application. If you think you have a grub infestation or would like to know more about this service, please contact one of the professionals at TDI Lawn & Pest to discuss options and timing of future preventative applications.