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How to Stop Grubs Before They Kill Your Lawn

May 13, 2012

Grubs are sneaky. There’s no way to tell when they invade your lawn, because they do their dirty work underground where you can’t see them.

Your lawn can look fine on top, while grubs are eating away at the roots, cutting off the supply of water and nutrients to your grass plants.

The visual warning of brown grass patches can be too late. Infested lawn areas often turn yellow and then brown after the damage is already done. In severe infestations, your sod can often be peeled back like a carpet. Unfortunately, the entire lawn may then have to be replaced.

Here is how the grub cycle works:

In early spring mature grubs awaken from hibernation and begin to work their way up from deep in the soil to just below the grass surface. In late spring, these grubs change into a pupae stage before turning into beetles that later feed on roses and other shrubs and trees in your landscape.

In summer, beetles burrow into the lawn and lay eggs that will hatch into grubs.

In late summer and early fall, newly hatched grubs feed heavily on your grass roots before hibernating for winter. It is during this time that young grubs do the most lawn damage as they gorge themselves prior to hibernation.

The good news is that you can kill grubs before they destroy your lawn. You can easily protect your lawn investment with a single application of Scotts GrubEx, which provides season-long protection.

The ideal application timing is May or June prior to the time when adult beetles lay eggs in your lawn. The GrubEx protection kills newly hatched grubs before they get large enough to damage your lawn.

GrubEx doesn’t harm earthworms, which are so beneficial to your soil. Even though you rid your lawn of grubs, you may still get the occasional mole in your lawn feasting on any earthworms living in your soil.

One last tip… Be sure to water your lawn after spreading GrubEx (click here for more GrubEx info).

Grubs eat grass roots resulting in brown, dead lawn patches in fall and early spring

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55 Comments
  1. David permalink

    I have had the occasional problem with grubs but an application of Grubex seems to work well. My problem is ants. I have had ant problems in my lawn since I bought this house many years ago. I have tried Scotts Turf Builder with Insect Control and many other insect killers with no luck. I think the ants colony goes down so far that the queen is not killed and they keep coming back. My lawn feels spongy in some areas due to the many ant hills. Is there anything that can be done to get rid of them once and for all?

    • Hi David
      Try spreading Ortho Bug B Gon MAX granules on your lawn. This product is especially good at killing ants. It also takes care of fleas, ticks and other lawn damanging insects (but not grubs).

    • K. F. Barnes permalink

      This is not a commercial product, but works very well on ants. Mix one teaspoon pure borax in one-quarter cup of mint-apple jelly. After mixing, heat in almost boiling water, mix again. Place mixture on pieces of rigid material (example: small tile). Place tile in lawn where ants are seen. Ants will find the mixture, eat the borax, return to the colony, they die, other ants eat them (including the queen) and they die. Takes about a week to completely kill a colony. And the ants find the colony for you !

  2. Frankie Henderson permalink

    Can you apply different applications of pests and weed controls at the same time.If not, can you give the timetables for applications.

    • Hi Frankie
      Some products can be applied together such as GrubEx and Ortho Bug B Gon (because they are both watered after application). Weed Controls are recommended to be applied when rain is not expected (times vary by product), so it would not be good to apply a product that should be watered after application. Some products recommend waiting a week between applications. All of this info is on the packages. If you want to receive specific recommendations for your type of lawn and your area, go to this link to sign up for free email reminders of what to apply and when:
      https://www.scotts.com/smg/profile/login/anonymousLogin.jsp?login=acctSubs&&_requestid=117758

  3. Natalie permalink

    I have applied nemotodes and Scott’s Bug Be Gone, but most of my lawn is very dry and brown/yellow. At this point, is it too late to salvage my lawn?
    Help!

    • Hi Natalie
      When lawns go dormant because of a lack of rain, they can stay in the brown state for up to 4 to 8 weeks and bounce back when the grass gets at least an inch of rain. Some grasses are better at bouncing back than others. One thing that will cause them not to respond to moisture is if there was insect damage. If you were able to water some after spreading your Bug B Gon, you should be protected. If you need more of an answer, let me know where you are located so I can understand what kind of lawn you have and what lawn problems you have in your area.

  4. Geraldine Jones permalink

    Can I treat my lawn for grub prevention now in August? The reason I need to know is that my neighbor has grubs and I don’t want them!!

  5. Liz permalink

    We just found that we have grubs. The lawn looks OK but is not as great as it was earlier in the year. Can we treat as it’s almost October? We live in north Florida and don’t expect it to get cold for several more months.

    thanks!

    Liz

    • Hi Liz
      Our GrubEx product needs to be applied before grub eggs are laid in late summer. Your young grubs should be controlled now if you have more than several per square foot. Since we do not have a product that I can recommend for active grubs, I suggest you check with your local garden center and ask for a grub control that will kill them now. Sorry we could not be more of a help with your problem.

  6. chris permalink

    i noticed in late October that I had grubs. A few people i talked to at the local box stores said it was to late to lay grub ex. My lawn i pretty bad and peeling back in a few spots. When is the earliest time i can lay it this year or is it to late and i need to reseed?

    • Hi Chris
      GrubEx works best when you put it down prior to grubs laying eggs… which means your April to June application protects you for grubs hatching out in late summer and early fall. So now the most important thing to understand is grubs do not feed on grass roots much in spring prior to turning into beetles. This means your grass could root (much like new sod) if it has good contact with your soil. About the time of your first mowing you might feed with Starter Lawn Food to encourage new roots. If your grass is too far gone to root, then you will need to seed this spring. Let me know if you need anymore info.

  7. Fred Reynolds permalink

    I had trouble with grubs last year. It’s early April in Chicago. Is it too early in the year to use a GrubEx type of material?

  8. Rob permalink

    Since GrubEx appears to kill only hatched grubs, why is it important to put it down before the eggs are even laid? Since the product works for up to four months, I’m worried that if I put it down in May that it’s effectiveness will end by September, i.e. late summer/early fall when the grubs are hatching.
    Also, when Scotts refers to applying a product during a certain season (say Spring) does this mean meteorlogical Spring (March 1st through May), astronomical Spring (March 20th through June 21st), or ecological Spring (using biological signposts e.g. the forsynthia bush begins to flower)?

    • Hi Rob
      A May application of GrubEx allows the time to get the most active ingredient absorbed into your grass plant to provide the protection from and killing of young feeding grubs in late summer. This timing also helps with Billbugs, Sodwebworms and other insects. My thoughts on your second question about the seasons are more in line with the biological signposts.

  9. Hello, I just discovered grubs in my planter beds. Does this product kill all stages of the weevil or just the larvae stage? Also, if they are in my planter beds, is it safe to assume they are in my lawn soil as well? Is there any harm in applying it everywhere to get rid of them?

    • Hi Courtney
      You are looking at grubs just prior to going into the pupae stage (when they do not feed on roots). The next stage is an adult beetle. (This is like a caterpillar turning into a butterfly.) This means that at this stage you generally do not worry about trying to kill them. Fishermen love this stage because they are great at the end of a hook. Now to your question, GrubEx is best applied prior to eggs being laid and then it does a great job of killing young grubs. So, an application next month takes care of the grubs that hatch from eggs in mid summer. Hope this helps answer your questions.

      • Thank you! So there is no way to kill them now before they become beetles? Aren’t they harder to kill once they are beetles because they can fly? Thank you!

      • Hi Courtney Ortho does not make a product to kill mature grubs just before they go into the pupae stage. You may be able to get a product at your local garden center that claims to this, however most folks ignore them at this stage. Adult beetles, like Japanese Beetles, can be killed with a variety of products. The best defense is to treat your lawn with GrubEx in May to stop the next generation.

  10. Ok Ashton, thank you so very much! They creep me out! :) I will be glad to get rid of them in May!

  11. Where do you buy Scotts Grub Ex

    • Hi Sharon
      GrubEx is commonly available at most Scotts retailers. Check with the Scotts Help Center: 800-543-TURF to find a retailer near you.

  12. sean permalink

    Is it ok if I have already spread new grass seed to affected areas while applying the Grub-Ex to the rest of the lawn?

  13. Helen permalink

    Hello all ,
    i live in ontario , just outside of toronto , we don’t get grub ex up here but we do have nematodes , i noticed the grubs and sprayed last week , will this be ok for my lawn ? and as of yesterday i still have grubs , my lawn looks like hell and i did put grass seed down , does anyone have any suggestions

    Thanks Helen

    • Hi Helen
      Any grubs you are seeing now will soon go into a pupae stage to turn into a beetle. They do not feed during this pupae stage (this is much like the cocoon stage that a worm goes thru to become a moth or a butterfly). I do not have a suggestion for you to prevent the next generation of grubs as we do not have GrubEx registered to sell in Canada. If you were in the states, you could put down GrubEx this month to prevent the next round of grubs in late summer/fall. You can try the nematode treatment for grubs, however I do not have any experience with it… Sorry.

  14. Josee Leger permalink

    Hello,

    I’m also from Ontario where we used to use Merit for grub control. It has since been banned. Quebec still allows the use of Merit but only by professional lawn care companies.

    Now, our ONLY option is the nematodes but I have had several applications and unfortunately the skunks, raccoons and crows love the juicy little guys dead OR alive! My lawn is a complete write-off :(

    I started looking at white clover as a grass alternative but the flowers attract bees and a friend who owns a lawn and pond care company suggested that grass is best.

    And this is why I love winter! LOL :)

    Josee Leger in Ottawa

    • Hi Josee
      I wish I had some suggestions for you. I am not familiar with the best timing and approach to use nematodes to control grubs. Some turf professionals establish the Turf-type Tall Fescues with the thought that grubs are not as much of a problem as with other cool-season grasses. Just look on the bright side… there are many good things about living in Ontario! Good Luck!

  15. Kjands permalink

    I have a well in the area of the grub and ant problem. Is grub x poisonous?

    • Hi Kjands
      I don’t think GrubEx will take care of your ant problem. Ortho Bug B Gon MAX will kill ants (however not grubs). I do not have a well, however if I did, I would not hesitate using these two products on my lawn.

  16. Lisa permalink

    Hi,
    I have cats that I let out in the back yard. We have grubs & ants and plan on using Ortho and Scotts on the lawn. Are these products harmful to my pets?

  17. Susan permalink

    Hi, my dogs eat grass when their tummy is upset, will it harm them? I’m afraid to put anything down for fear of poisoning. Also, I live in dry hot climate, do I need to water deep when I apply? My grass was fantastic up until two summers ago, I noticed spongy dry yellow areas. I’m so frustrated.

    • Hi Susan
      Our cat also eats grass. Before I answer your question about your dog, I am not sure you have had a grub problem based on your description. Let me know the city, state where you live and any info you know about your grass type. Also, if you can tell me what you have put on your lawn so far this spring that would be a big help. GrubEx is ok to use if you have pets. Keep pets off the lawn while you are spreading. Water after application (around a quarter to half inch). Then when the lawn is dry your pets can return to the lawn.

  18. Terry permalink

    I live in Michigan. This year seems like much of the community I live in has experienced a population explosion of grubs. So many lawns look so terrible this year with the same brown patches as mine. I’ve never had any grubs before this year. It became apparent in late May – mid June that i noticed the patches and I dug around in them and found white grubs curled into a “C shape” with brown heads. They were about the size of a nickel or even larger.
    The “patches” I found were only in one area of my yard and I fear next year it will be worse. There were about 8 – 10 in that area that I found and got too grossed out to look for more!

    I am wondering what type of grub they are and what method best to cure this problem overall. I understand there is a cycle I need to break. It is now almost August and I need to know what I should use and when.to break this cycle. I hear it depends on what type of grub they are. Can you lend me some advice on how to handle this?

    • Hi Terry
      The most common white grub in many areas of Michigan is from Japanese Beetles. GrubEx takes care of grubs from 11 different kinds of beetles. If you have not applied GrubEx yet this year, you still have time. Put it down ASAP and you will get protection from the grubs that will hatch in late summer and early fall. Water your lawn after spreading.

  19. Nicole Brereton permalink

    Hi I had the black beetle in my seeded lawn last year and have just poisoned the lawn as I am wanting to turf the lawn.I have taken up the dead lawn and it is now all just soil but have noticed some black beetle in the soil what should I do?Should I treat the soil with the GRUBEX?am I going to be able to turf?I live in Australia and the we are currently in spring and summer starts in November here?Any suggestions would be great?

  20. Holly permalink

    We just laid 3200 square feet of sod and noticed about 10-20 baby grubs in the sod. Is that enough to worry about? I do not want our money spent on sod completely destroyed before it even has a chance to root! We live in bakersfield, ca so we are extremely dry and water three times a day right now.

    • Holly permalink

      The baby grubs we saw are about 1/4 inch long.

      • Hi Holly
        I do not think you are finding enough grubs to be concerned about. Keep your sod watered until you can feel root resistance when you try to pull it up. Ask your sod installer if they fed it when they installed. If not, feed about a month from now with Scotts Turf Builder Lawn Food for New Grass. If they did feed when installed, feed a month from now with Scotts Turf Builder WinterGuard. You are living in an area that can grow many kinds of grasses, however I would suspect that you have Bermudagrass. If so, only one more feeding this year will likely be enough.

  21. Carmen permalink

    Help My grass was dying and sure enough I have Grubs so I went to home depot got grub x I borrowed a hand spreader and it went to fast so back yo home depot and got another one and my own spreader. well its been like 3 weeks and I was pulling some dead grass and yikes baby grubs Help!!! I am women and not good at this lawn stuff Please help (MI)

    • Hi Carmen
      GrubEx is best applied between April and August to prevent grubs from becoming a problem in fall and next spring. It knocks off the grubs as they hatch from the eggs in late summer so they do not destroy your lawn’s roots. I am sorry to say that an application this time of year will not do the job on grubs. We do not have a product to use this time of year on grubs that are already in your lawn. You can check with your garden center to see if they have a grub control that will work this time of year. It is generally sold as controlling grubs fast, however it does not provide longer lasting prevention.

  22. Deepa permalink

    I have these grubs eating my whole backyard . They just cAme a month ago. Anything I can do before my whole yard is destroyed. I am in tears

    • Hi Deepa
      I am very sorry to say that I do not have a recommendation from Scotts or Ortho to kill active grubs this time of year. Our best approach is to prevent grubs from getting to the stage you are experiencing by spreading some GrubEx anytime between April and August. There may be some product options that provide quick grub kill this time of year…. check with your local garden center. Sorry I could not provide a solution.

  23. Mike permalink

    Anyone needing a FAST ACTING for grub, should use BAYER 24 hour, if they missed the GRUB X and grubs are starting to eat,. If you put it down before a light rain ( 1/2 inch predicted) you will find LOTS of DEAD grubs after it. It kills them dead NOW.
    Be sure and use the GRUB X in May as told here, and you won’t need this info!

    I happened to catch grass turning one year in about August, and dug down a little with my fingers and found lots of grubs. They were dead in 24 hours as described, but I put it down right before a good 1/2 inch rain. Grass immediately started comong back.

    Now I just use Scotts in May and let them go away.

    (moderator- delete my last post!)

    • Hi Mike
      Thanks for your input. Grubs are a lot harder to kill in spring than in August as you experienced. In many cases they do not need to be killed in spring as they do very little feeding prior to going through the pupate stage to become beetles. Your advice to put down GrubEx in May is right on!

  24. Danielle permalink

    Hello, I live in Massachusettes and my neighbor who has a beautiful lawn has been overrun by grubs this year and has distroyed his lawn. I am now worried about them coming over to our yard. I have been reading your comments about the Grub Ex, do you think I lready have them? And I know the gGrub Ex is preventative but would help me now if I do have them? Thank you for your advice!

    • Hi Danielle
      Grubs are about to move into their non-feeding stage as they go through the process of becoming adult beetles. If you had a big infestation now, you would have seen the damage last fall and this spring. A healthy lawn with a robust root system from regular feeding can tolerate a few grubs per sq. ft. Your best approach is to put down GrubEx sometime in the next few weeks when a rain is forecasted so it gets watered in good and then you will be protected from the next generation of grubs that will hatch from eggs laid by beetles this summer.

  25. Arthrup J permalink

    I have been very happy with milky spore for organic grub control.

    http://matthewgustke.com/2014/04/02/organically-controlling-tomato-hornworms-white-grubs/

    • Hi Arthrup J
      Thanks for passing along your experience. Sounds like you are one of the lucky ones based on this report from Michigan State Extension Service this spring:
      http://msue.anr.msu.edu/news/what_are_the_alternatives_to_grub_control_insecticides
      I think one of the difficulties is that Milky Spore is only for Japanese Beetle grubs and not other white grubs. Japanese Beetle Grubs need to be present in the soil to ingest the milky spore bacteria and then die from it to inoculate the soil and this takes several years. During that time nothing can be put down to kill grubs as that would mean the soil would not be inoculated. After all that, one could have one of the other kinds of white grub species wipe out their lawn even though the Milky Spore is present.

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