Lawn Grubs: How And When To Kill Them
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Is there anything more damaging than grubs in your lawn?
Few admire their looks. But, before dismissing them as nothing but gross menaces, grubs the larval stage of certain adult beetles are common in lawns and do play a role in the natural order of things .
David Shetlar is a professor emeritus with a doctoral degree in entomology at The Ohio State University. Hes also co-author of the comprehensive guide Garden Insects of North America, plus other pest management tomes including Managing Turfgrass Pests.
Shetlar chuckled brightly when asked if lawn grubs, commonly called white grubs, play a positive part in a lawns ecosystem. Everybody says grubs eat the grass roots, he said, but theres more to them than that. White grubs are eating the accumulated thatch and organic matter thats in the top inch of the soil profile.
Theyre sort of natures de-thatchers, he added. But the problem is, theyre eating that thatch, they do eat the roots and the crowns , which kills the plant.
Its when these de-thatcher populations grow out of control that the dreaded lawn damage takes place.
Short on time and just want to kill some grubs? Here are our picks for the best grub killers.
When To Apply Grub Control In Iowa
It is best to use grub control pesticides as soon as symptoms of an active infestation show, which is generally later in the grasses growth season. Grub control insecticides are available at most garden centers. In order to get the most benefit from a prophylactic treatment against grubs, administer it right before the grubs hatch which is often late spring or early summer.
In Iowa, the months of June and July are the best times to use a preventative pesticide to control white grubs. Home gardeners can use preventive insecticides such as chlorantraniliprole and imidacloprid, which are both available over-the-counter .
How Can I Naturally Get Rid Of Grubs In My Lawn
If youre dealing with Japanese beetle grubs, milky spore is another natural bacterium that may assist. Allowing grubs to dry out is another easy method to destroy them. They can only grow in wet soil and will perish if there is a drought. If you dont water the grass, you may be able to get rid of them.
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How To Treat Grubs In Minneapolis Lawns
Here at KG Landscape, we think of the two weeks of the Minnesota State Fair as a great time to apply insecticides for grubs. By that time, the grubs have had enough time to start feeding on the roots and be very close to the soil surface but they are still small and easy to kill. The best treatment for these grubs is a chemical called Imidacloprid. It is safe for mammals and most fish so it has a small impact on the local ecosystem but does kill the grubs damaging the grass. We use a granular treatment that only requires one treatment per year until they are completely eradicated. It may or may not effect some honeybees, but if applied to only grass areas with possible grub damage, the impact on these important creatures will be minimal.
If youre looking for lawn help in the Minneapolis/St. Paul area, look no further than KG Landscape. We have the experience and knowledge to help fix any lawn issues. Give us a call at our office 763-568-7251 or fill out a quote request and well get in contact with you. Getting that golf course quality grass shouldnt be impossible we can help make it happen.
Grub Control: How To Get Rid Of Grubs In The Lawn
Grubs are one of the areas most common and destructive lawn pests. They cause the lawn to decline or die out in late summer and early fall. Grubs feed on the roots of healthy grass, limiting the plants ability to uptake water and nutrients. The most common turf species in our area, tall fescue and bluegrass, are both potentially affected.
Damage is most severe in the sunny parts of the lawn. Highly maintained lawns, those watered regularly during the summer, are more likely to suffer damage than low input turf. Controlling grubs before they cause the below ground damage is often a challenge and confusing. Success in controlling grubs is a combination of knowing the grubs habit and proper chemical selection and application.
Identifying grubs and their life cycle
Grubs are the white C-shaped larvae of several types of beetles including June bugs and southern masked chafer. These ravenous feeders can be found almost year-round. In fact, finding a few grubs can be a sign of healthy soil.
The most common grub species is the southern masked chafer, which has a very predictable life cycle. Understanding that cycle aids in proper control strategies:
- Adults lay eggs in the lawn during early to mid-summer.
- These eggs hatch in mid-August and start to feed. It is this feeding period that damages the lawn.
- Winters arrival forces the grubs deep into the soil.
- Come spring they move back to the soil surface and prepare to emerge, starting the cycle over.
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Tips To Keep Grubs From Destroying Your Lawn
Grubs can destroy a lawn quickly. You wake up one day and a greening up lawn isn’t greening up. You might have grubs. Here are the main things you need to know to keep grubs from killing your lawn.
First I should say that some of the grub killing chemicals are thought to likely harm bees. We need bees for pollination and food. So if you don’t mind dead spots in your lawn, skip the chemicals.
The first step in proper grub control is knowing the size of your lawn. You can’t even go to the store and buy grub control products without knowing how much area you are treating. You don’t have to be exact down to the square foot. Try to get to within 1,000 square feet.
The next important thought is put down the correct product. Grubs go through a few life cycles. Different chemicals kill grubs at different life cycle phases. If you put the wrong product down for the current grub life cycle, you will have wasted your money and not killed the grubs.
Imidacloprid is the most reasonably priced grub control, but it only works on the early life cycle of grubs. Imidacloprid has to be applied in July to possibly early August. The experts advise applying it in the first two weeks of July. The chemical will remain in the roots through fall, and kill any small grub. That takes care of your grub control until the next July.
If you are just starting with grub control, I’d start with chlorantraniliprole.
Do I Need To Apply Grub Killer Every Year
You dont need to treat for grubs every year because a preventive pesticide application should kill a majority of the grubs that are likely to cause damage the next year. Grubs in your neighbors lawn are unlikely to spread to your lawn every year, so only treat when you see the signs of grub damage.
In fact, a healthy lawn can tolerate a few grubs here and there without showing any signs of damage. You only need to start treating the lawn with a grub killer when you see irregular patches of dead grass and also put down a grub preventer as a precaution for the next year.
For prevention purposes, put down lawn insecticides with either thiamethoxam, imidacloprid, or chlorantraniliprole as the active ingredients once every 2 years early in the spring. Follow the instructions on the product label to guide you on the right time to apply the grub control pesticide because some products last longer in the soil than others.
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White Grubs What Are They
White grubs are the immature phase, or larvae, of beetles in the scarab family. In Minnesota, white grubs are typically the larvae of May-June beetles and Japanese beetles.
Like all beetles, white grubs undergo complete metamorphosis. Adult beetles lay their eggs in the ground, where the eggs hatch and the beetle larvae live. The beetles progress through the egg stage, several immature stages, and a non-feeding intermediate stage to the adult stage.
The bodies of white grubs grow considerably throughout their life cycle and they move within the soil. White grubs cant tolerate freezing temperatures when temperatures cool in the fall, larvae move lower in the soil, below the normal frost line, to survive winter. When the weather warms, they move up to feed on roots.
Different species of white grubs look similar to one another but can be distinguished by the arrangement of hairs and bristles on the underside of their abdomen at the tip called a raster pattern. Raster patterns are challenging to see and recognize an expert should identify any pest grubs.
Management will differ based on what species of white grub is present in your yard because they have different timing for their life cycles, which means different timing for management.
Recommended Practices As You Use Pesticides
1. If you decide to use a pesticide to kill the grubs, it will probably be toxic to good insects like bees and other pollinators as well. To protect them from harm, mow your lawn before you apply the chemical to get rid of flowers that may attract them. 2. Water your lawn after you apply the pesticide to avoid burning your plants and to enable the soil to absorb it.
3. Dont apply too much pesticides as it will run off your lawn and into the environment. Use only the recommended usage on the back of the bottle.
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How To Check For Grubs In Lawn
Before you start treating, it is important to check to make sure that indeed there are grubs damaging your lawn. Irregular brown patches of dying grass are the first sign. If you see the patches, lift the turf to check for the grub worms.
Take a shovel and dig a square foot about 3 inches deep and lift the turf to check for grub worms. If you find one or two grubs is normal and healthy, but if you find 5 or more grubs, you have a grub worm infestation that needs treatment to prevent further damage to your turfgrass.
Is It Too Late To Treat For White Grubs
Damage from white grubs in lawns can show up anytime after mid-August. However, our experience in the recent past has been that grub damage does not become obvious until September or even into October. Damage from white grubs is usually localized. It is typical to have severe damage in irregular and isolated spots where there were enough soil-dwelling larvae to eat the grass plant roots.
White grub damage may first appear as drought stress . More severe damage causes the turf to die in large irregular patches that can be rolled back like a loose carpet. High populations of grubs may go unnoticed until discovery by raccoons or skunks. Raccoons, skunks and crows will turn over large patches of loose turf, eat the grubs and leave behind a torn-up mess.
Rainfall and soil moisture are critical factors affecting the extent of grub damage. Adequate moisture in mid-summer will favor beetle activity and grub development. If plentiful rainfall or irrigation continues through August and September damage may not be noticeable because the grass continues to grow and masks the root injury symptoms. Healthy turf can sometimes tolerate 20 or more grubs per square foot before showing signs of injury. The onset of dry weather can lead to sudden” appearance of grub damage symptoms.
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How To Apply Grub Control
Having identified the most active months for grubs, its time to hit them hard with effective strategies to keep them at bay.
First, youll need to wait for visible signs. However, we all know that grubs are root feeders and wont be easily seen as they are below the ground surface.
Youll have to wait for signs of their feeding activity. This is usually seen when your lawn grass begins to look drought-stressed or brown patches begin to emerge.
To further confirm grub presence, you may have to tug at certain sections of your lawn grass.
If there are signs of slight movement, lifting or pulling the grass out will reveal grubs. Youll always find these destroyers lying in a C shape and looking innocent. You may want to also introduce a natural predator onto your lawn.
Common grub predators include birds and other small animals who will have a field day fishing out grubs from their hiding/feeding spots. Combating this problem can be achieved using a variety of ways.
Some of the common methods include the use of detergent solutions or Dawn dish wash soap among other natural techniques. If youre not specific about the strategy used in getting rid of grubs, consider using insecticides.
These are applied to the lawn following the use instructions which accompany the insecticide.
Controlling Grubs In The Lawn
Beetles, like Japanese and chafer beetles, emerge in early summer, feed on plants in the garden, and lay their eggs in the soil in the lawn. Later in the summer, the grubs hatch and immediately begin to feed. They will continue to eat and grow until mid-fall, when they move deeper in the soil so they can survive through the winter. When the soil warms up again in the spring, the large, mature grubs move back into the upper soil levels, where they transform into adult beetles that emerge in early summer and start the whole process over again.
The key to controlling grubs is to kill them before they hatch and begin to cause damage to your lawn. In spring or early summer, apply a preventative grub control product, such as Scotts® GrubEx®1 to your lawn, following label directions. This is especially important if youve had problems with grubs in the past. One application of Scotts® GrubEx®1 can kill and prevent grubs for up to 4 months.
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Is It Too Late To Apply Grub Control
Preventative measures work best before the fall season. But if perhaps fall meets you unprepared, you could still take your bet at saving your lawn.
For lawn owners, Imidacloprid is one of the most common grub control treatments. Usually, products with Imidacloprid are usually most effective when applied during summer, probably at the end of July or at most early August.
However, there are other newly emerging products that could control the damage of late application. These products still work just fine even right into September.
Even if you couldnt take your shot at grub preventative treatments, you could always go for curative control.
The Best Time To Apply Grub Killer
The question of when to put down grub control can be answered only after defining the type of pesticide being used.
If you know your lawn already has a pest problem and this year, you want to nip it in the bud, and you might choose a grub preventer.
- Grub Preventer should be applied shortly before the grubs hatch you may have noticed in previous summers when this was, due to sudden brown patches and lawn damage. As a rule, this is usually early summer, but take a look at our chart below for a more accurate timeline.
However, if you find yourself well into the growing season and have started to notice damage to your lawn due to grubs, it is too late for a preventative. At this point, you will need to apply a regular grub killer.
- Grub control, when applied correctly, will get rid of the pests it comes in contact with and therefore, can be applied anytime you notice the grubs are active. This usually coincides with your lawns growing season.
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To Deter Lawn Grubs Dethatch
But what are the most effective options for sustainable-minded lawn owners?
Preventive methods top Shetlars list for fighting grubs nonchemically. I emphasize a lot especially to lawn care and sport field managers to keep the thatch down to a minimum, Shetlar said. His key to this: fertilizing ones lawn with nitrogen only once per year, and doing it very strategically and judiciously, to quote Shetlar, usually in late October, early November.
He also mentions research from a University of Kentucky entomologist suggesting you should choose one species of turfgrass over another.
Professor Daniel. A. Potter has conclusively shown that the tall are much more tolerant of grub populations, said Shetlar, who then added, Where Kentucky bluegrass and perennial ryegrass will be damaged with eight to 10 grubs per square foot, the tall fescues usually require somewhere around 12 to 14 grubs per square foot before showing damage.
What about those common organic recommendations for killing lawn grubs online, such as milky spore disease or beneficial nematodes? The commercial milky spore disease is only for Japanese beetles, Shetlar warned. Even then, milky spore disease is a weak pathogen that results in 20% to 25% infection at best.
As for beneficial nematodes, Shetlar said, Theres a very steep learning curve to using the insect parasitic nematodes. They can only be effective when used curatively, and even then, only on small affected areas.
Are Grubs Taking Over Your San Francisco Bay Area Yard Were Here To Help
Grubs can do severe damage to your yard. Fortunately, you dont have to accept those brown, dead patches any longer.
Here at Smiths Pest Management, our team knows how to get rid of grubs in Bay Area yards, gardens, and flower beds.
Using traditional and eco-friendly techniques, well solve your grub problem and restore your beautiful, green yard.
Contact us today to schedule your pest control inspection or to request a free quote.
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