If you’ve spent any time doing research about lawn care, you’ve probably heard about grubs. These little creatures can wreak havoc on your lawn, often before you even realize that there’s an issue.
And when you do spot an issue, you need to act quickly, or you will find yourself replacing all of your grass in short order.
So what are grubs, anyway? In the simplest terms, they are beetle larvae; more specifically, the larvae of scarab type beetles such as Japanese beetles, June bugs, or European chafers. They usually appear in the springtime, when they awaken and begin feeding on your grass roots.
Come summer, they turn into beetles, and eat your flowers and garden foliage before dying in the fall – but not before they lay eggs in your lawn for next year’s generation of hungry insects.
Grubs aren’t only a problem because they feed on your lawn and kill the grass. Grubs are food source for critters like raccoons, voles, and birds, who won’t hesitate to dig up your lawn to find the tasty larvae.
An increase in activity from these types of creates usually indicates some type of insect infestation in your lawn, so it’s best to act when you spot signs of trouble.
Even healthy lawns can hide grubs, but if you follow these lawn care tips, you can keep them from completely destroying all of your hard work.
The good news about grubs is that there are usually obvious signs – like animal activity – that they are present. The bad news is that those signs only appear once the bugs have taken hold.
In addition to holes dug by animals, you can assume you have grubs if:
The only way to know for sure if you have grubs though, is to look. The best way to do this is to cut a one-foot square patch of grass about 2-4 inches deep. If you have a problem, the patch will easily lift up and roll like a carpet, and you’ll be able to see the root damage.
You’ll also be able to see the actual grubs in the dirt: little white C-shaped bugs throughout.
Having some grubs in your lawn isn’t necessarily an issue. Most healthy lawns have at least a few grubs, sometimes as many as nine or ten per square foot. If your visual inspection reveals fewer than five grubs per square foot (and you should check multiple patches of lawn) then you don’t have a serious grub problem.
Any yellowing or dying is due to another problem. If you have 6-10 grubs, and the lawn is otherwise healthy, you may wish to treat only if they are causing visible damage or if animals are digging to get them.
If there are more than 10 grubs present, then you have an issue and need to treat your lawn for grubs. You have two options: Preventive and curative treatments.
Dealing with a grub problem usually means using a pesticide. A preventive application in the spring will kill the grubs that have already hatched, and keep new ones from hatching throughout the season. Because preventive pesticides are typically combined with fertilizer, it’s important to apply them in the spring, so they don’t burn the grass.
Watering is also important, to ensure that the pesticide reaches deep into the soil where the grubs are hiding.
A curative application is in order if you discover a widespread grub problem. These pesticides will kill the larvae on contact, but don’t work for as long. It’s usually best to call a professional for curative pesticides.
Watering your lawn appropriately can help control the grub population. Grubs love moisture – and tend to die out in drought conditions – so watering your lawn infrequently but deeply can help keep grubs away by preventing the soil from being too moist.
Keep an eye on how your neighbors’ lawns look as well. Grubs are rarely limited to one yard, so if you see signs in your neighborhood, it’s likely you have the pesky critters as well.
Grubs are a natural part of your lawn’s ecosystem, but you don’t have to let them wreak havoc. Be alert to the signs and act when you see them, and you will keep your grass from falling prey to these pests.
I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.