Lawn Grubs

How and When to Kill Them?

Common in yards nationwide, lawn grubs—the larval stage of some adult beetles—do contribute to the natural order of things, but only in the proper quantities. However, you will want to know how and when to eradicate the grubs from your lawn when the populations become unmanageable.

What are Grubs?

In reality, a grubworm is an insect larva (such as a beetle or chafer) rather than a worm. What do grubs consume? Lawn grubs consume the organic stuff in the soil and eventually eat the grassroots, which is bad for your lawn.

They’re kind of natural, but the issue is that they eat the roots and crowns of turfgrass, which kills the plant if they’re eating thatch. Grubs can destroy your lovely grass, which is what they can do to your lawn.

Grubs are especially detrimental to your garden since, as larvae, they consume the roots of your plants, and as adults, they can consume the leaves of any plant they come across.

Signs of a Lawn Grub Problem

All grasses can withstand a certain amount of grub feeding, but know when it becomes excessive. Grubs are sometimes not even found until the raccoons and skunks begin to dig them up. Check your lawn for the following indications of grubs:

• Thinning the lawn every week, dead spots get bigger.

• At the roots, grass will pull out rather readily.

• Animals begin excavating in the lawn, particularly raccoons, ravens, skunks, and moles.

• In search of a location to deposit their eggs, beetles or moths fly around, generally at a low altitude.

• A springy sensation while strolling on the grass.

• Even if there is plenty of water and no drought, there are indications of it in the grass.

How to Scout for Lawn Grubs?

Scouting for grubs is the only method to be certain that they are present on your lawn:

• Take a foot of your grass and cut it in. If you suspect grub activity in an area, you can use a grass edger or a shovel.
• Remove the dirt from that cut. If there is grub damage, the grass on your lawn will peel up quickly.
• Go through the soil and count the grubs you come across.
• Count the number. A significant grub infestation is present if there are ten or more grubs per square foot.
• The grass you chopped should be replaced. You don’t want the yard harmed.
• Go through the procedure again. Be careful when scouting different areas of the grass.

Getting Rid of Lawn Grubs

Here are two methods for getting rid of grass grubs now that you know what they are and how to spot them:

• With preventative methods
• And curative methods

Preventative

The best defense against grass grubs is prevention. Use these pointers to avoid grubs in the first place and get rid of them from your lawn:

• Dethatching is key. I stress a lot on managers of sports fields and grass maintenance, in particular, [to attempt] to minimize thatch. Nitrogen fertilization of the grass should only be done once a year, and it should be done carefully and strategically, generally in late October or early November.
• Aerate your lawn. Since grubs consume the thatch of compacted soil, aerating the lawn can help prevent their spread by stimulating root development and breaking up the thatch layer.
• Think before you mow. Be careful to mow your yard properly. For efficient grub control on your lawn, use the highest setting on your mower, which may be between 3.5 and 4 inches. As a consequence, the root system will become deeper and more robust. If you fertilize in the spring and mow your lawn high, you might be able to avoid applying a grub killer.
• Choose the right turfgrass. University of Kentucky entomologist A. Potter showed that the tall [fescue grasses] are far more tolerant to grub infestations.

“Tall fescues typically need 12 to 14 grubs per square foot before they exhibit signs of damage, but Kentucky bluegrass and perennial ryegrass will only need eight to 10 grubs per square foot.”

• Deny moisture to the grubs. Ensure your grass stays dry during July and August to avoid beetle eggs drying out and dying. If your grass turns brown, you may water it more because there won’t be any long-term damage.
• Turn to chemical insecticides. The preventative grub treatments imidacloprid, thiamethoxam, and clothianidin benefit lawns. Depending on where you live, the best time of year to apply these pesticides is from mid-April to mid-June. Waiting until brown stains appear is too late.

Note: Any use of pesticides puts other insects, particularly pollinators that help lawns, at risk of injury in addition to humans. One way to lessen the impact is to mow your grass just before applying so that weed flower heads won’t draw pollinators to your momentarily poisoned yard.

Curative

What happens, though, if you have an active grub infestation? The use of curative techniques is another aspect of grass grub control. You can address active infestations with these methods. The grubs in your lawn can be treated as follows:

• Trichlorfon and carbaryl are regarded as curative measures. When you see grubs in the grass, you apply them. These are transient products that take action right away. Reassess the lawn the week after the treated grubs turn yellow or brown to see whether the pesticides are effective.
• Milky Spore Disease: Milky spore disease is another way to combat grubs on your grass. The commercial milky spore disease is exclusive to Japanese beetles. Even yet, milky spore sickness is a weak pathogen that, at most, causes 20% to 25% infection.
• Neem oil is a safe and efficient way to keep grubs away from pollinators. To make your remedy, follow the directions on the packaging to combine neem oil with water. Apply the solution to your yard with a hose-end or pump sprayer. Apply early in the fall or late in the summer.

• Grubs are killed or weakened by naturally existing diseases (bacteria, fungus, and protozoa); these pathogens are already present in the soil, but the chemicals you use will destroy them. For this reason, you may wish to postpone any further chemical grub treatments and allow the pathogens to do their job. Beneficial insects that consume eggs and juvenile grubs include ants and ground beetles. Older grubs are targeted by parasitic flies and wasps.
• The use of insect parasitic nematodes has a very high learning curve. Only when applied curatively, and even then, only on tiny, damaged areas, may they be an effective therapy for grass grubs.

Nevertheless, Shetlar hints that the most skilled organic lawn care providers would be skilled at employing beneficial nematodes as successful lawn grub killers. “They function pretty well in that situation,” he stated. “When used properly and at the appropriate time, nematodes can usually achieve 60% to 100% control.”

When to Treat Your Lawn for Grubs

Generally speaking, in summer or early autumn when the eggs have not hatched yet or the grubs are still little, is the ideal period to use preventive grub control products—mid-April to mid-June. Should you miss this opportunity, treat grubs in the grass curatively and start as soon as first grub damage shows up.

When to Call Pest Control Pros

Should your count reveal more than six grubs per square foot, you should act and treat your grass for grubs. Do not wait till you have a major infestation.

Always laugh about [evaluating the threshold] as raccoons and skunks have not heard about this barrier. There are four to five grubs per square foot, generally plenty for them to burrow about.

It can also be sufficient for you to bring in local lawn pest treatment experts so they may eliminate grub worms and prevent further harm to your grass.

Life Cycle of Lawn Grubs

Grubs do not arrive from the skies, just as newborns do not come from a stork carrying them in a basket. Where, thus, do grubs originate? Lawn grubs go through this life cycle:

• Summertime brings insect egg-laying. There were European chafers in late June and Japanese beetles in July and August.
• The eggs hatch two to one week later, and the baby grubs start eating grass roots.
• Grub egg death falls between July and August. Dry soils produce moisture stress, which causes the eggs to perish.
• The grubs in your yard eat until autumn, then burrow far into the ground.
• Grubs dig deep in the grass and overwinter in winter.
• Grubs climb upward into the grassroots in April and start feasting once again.

Lawn Grubs: What They Look Like

Grass grubs, if you have never seen them before, resemble this:

• Though they may vary in size, white grubs have a similar look.
• Though size varies depending on the species, fully mature adult grubs may span 3/8 inch to over 2 inches.
• Grubs have brown heads and a cream-colored body. Their tiny legs count in three pairs.Usually coiled into a C form, soft bodies.
• Adult bugs have oval shapes. Their length runs from 3/16 inch to 1 inch and may be green, tan, brown, or black.
• Since most species are nocturnal, they are not easily seen. Often, they are only observed when drawn to outside lighting.

Kinds of Lawn Grubs: They All Do the Same Damage

What species it is is unimportant, of course. Their injury is of the same kind. However, the following types of grass grubs are likely to be found just outside your house:

• Widespread invading pests, such as Japanese beetle grubs, are found on lawns nationwide, thanks to their white grub larvae. Daytime mating of Japanese beetles may be seen at their feeding places.

• Like other white grubs, Asiatic garden beetles are light brown as adults and white with a brown head as grubs. In some regions, they are beginning to outnumber the Japanese beetle. At night, lights attract nocturnal Asiatic garden beetles.

• White grub infestations also result from chafer species, chief among them the masked chafer beetles (like the European chafer). At dusk, close to trees or chimneys, European chafers fly mating flights.

• May beetles: May beetles, also known as June bugs, belong to the extensive family of scarabs.

• Black turfgrass ataenius:Though usually seen on golf courses, this glossy black adult beetle may be found in grass.

No Time to Wait

Wait not for lawn grubs to ruin your grass. Take care in choosing and tending to your lawn to help you notice them before then. Should you still get them, do not delay. If you are thinking about chemical lawn grub treatments specifically, be ready to call in lawn pest experts.