AUGUSTA, Maine — The latest scientific research says if your spring lawn damage is being caused by grubs, this is not the time to manage them.
“Springtime is not the best time for grub control,” says Jim Dill, manager of the University of Maine Cooperative Extension Pest Management Office in a press release. “As they emerge from winter, grubs are mature and this is when they are least susceptible to pesticides. Wait until mid-June to apply a grub-control product. This will allow the insecticide to get fully incorporated into the soil to control the new grubs which are just hatching, are closer to the surface, and are more susceptible to the effects of pesticides. Trying to treat grubs in the spring by the homeowner is simply a waste of time and money. And, when they don’t seem to be working, there’s a tendency to over apply control products, and that’s when excess chemicals run off into our water supplies, and can be harmful to human health and the environment.”
Grubs have been plaguing the lawns of many homeowners in Maine over the past few years, especially in the Bangor area and southern regions of the state, according to the press release. Brown patches on the lawn may be caused by grubs, but not necessarily.
“Before you do anything, there are some important points to consider,” adds Dill. “First, you must be sure that grubs are the problem. Browning lawns can also be caused by drought, poor soil, disease, or other organisms. And, even if the grubs are positively identified, are they in sufficient numbers to really cause significant damage? Sometimes, reseeding the brown patches is all that can be done. There are also biological controls, like beneficial nematodes, that may be successful. If you contact us at the Pest Management Office, we can help you identify your problem and provide many options for how to solve it.”
Grubs, which are the white, immature, C-shaped form of beetles, most notably Japanese beetles and European chafers, feed on the roots of grass, killing it and causing the brown patches, according to the UM press release.
From beetles emerging from the ground in early summer, through three distinct stages of grubs ending in the fall, keeping track of grubs can be difficult. The lawn damage you see in the early spring is actually the result of late summer, fall, and winter feeding. When the grubs are fully grown in the spring, with the largest appetites, they continue to add to the fall-feeding damage, but it is usually far less noticeable.
It may be a good idea to hire a professional lawn care company to deal with the problem.
“When grub-control products are applied at the wrong time, not only do they not work, but many, many pounds of pesticide products are being applied that don’t need to be and they can end up where they shouldn’t,” Deven Morrill of Lucas Tree Experts, a Portland-based company that also does lawn care, said in the press release. “As we professionals do, when homeowners apply products to their lawns, it is most important to read the label carefully, follow it exactly, and be sure it’s the right product for the problem at hand, applied at the most effective time. Licensed applicators must also stay tuned to the latest research and apply it when it’s proven effective.”
For help with a grub problem, contact the Pest Management Office at 800-287-0279. The office also maintains the website http://extension.umaine.edu/homeowner-ipm/. Another resource for additional information on grubs can be found on the Got Pests? website, http://www.maine.gov/agriculture/pesticides/gotpests/bugs/grubs.htm.