Grub Dilemma

Kentucky bluegrass, Fescue, Rye and Bent, etc
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KBGkicksazz
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Grub Dilemma

Post by KBGkicksazz » May 15th, 2019, 1:02 pm

I seeding my new KBG lawn last year so this is the first spring. I put down the grub ex preventative product about a months ago with lots of rain the last several weeks.

Decided to add a tree and shrub bed to my front lawn.
While digging and putting in the tree and shrubs I saw several living grubs.

Should put down a grub killer as I’m surprised to see grubs so early in the season.

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HoosierLawnGnome
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Re: Grub Dilemma

Post by HoosierLawnGnome » May 15th, 2019, 1:24 pm

Some are ok. It's when you get a dozen per SF you have to worry about it.

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ken-n-nancy
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Re: Grub Dilemma

Post by ken-n-nancy » May 15th, 2019, 1:28 pm

First off, the go-to article to understand preventative and curative grub treatments, different products, and the different timing required for different products is the annually-updated article from Michigan State University: https://www.canr.msu.edu/news/how_to_ch ... _your_lawn

I believe you will find that the article will give you the information needed to help you determine how you should proceed. I highly suggest you read the article. If it doesn't make sense to you, read it again a day later -- you'll pick up more on a second reading that didn't make sense the first time through. I reread the article just about every year.

I'm hesitant to even provide my quick interpretation, as you reading what I have to say isn't a very good substitute for taking the extra time to read the article.

However, rather than seem like I'm ignoring your question, here goes...

The grubs you are seeing now are likely relatively large, nearly mature grubs. They will pupate soon, and remain as pupa (like cocoons) for a few weeks, then emerge as adult beetles this summer.

The GrubEx you applied this spring will *not* kill those nearly-adult grubs. The pesticide is not sufficiently concentrated and potent to kill the nearly mature grubs. Rather, the GrubEx you applied recently is targeted to kill the grubs in the next annual cycle -- it will kill the baby grubs that will be hatching from eggs laid by the adults over the summer. Essentially, the product you applied this spring of 2019 will kill the new crop of baby grubs that would otherwise be eating your grass roots in the fall of 2019 and spring of 2020.

In order to kill the grubs in your lawn right now (which are going to be done eating in a few weeks and becoming adults) you would need to apply a curative product. Scotts GrubEx is not that product. The MSU article provides specific guidance for products to use for that purpose. A few grubs are tolerable by a healthy lawn.

The advantage of the preventative products is that they provide relatively targeted control (affect primarily only the target pests) and can be used at lower dosages, since they are killing baby grubs, not nearly-mature adult grubs. They do an excellent job of breaking the perpetual life cycle, and are sufficiently targeted and low-impact to the environment that they can be used every year.

Rather the curative products are relatively broad spectrum and will kill many other types of insect life in the soil (even beneficial insects), and require higher amounts of the active ingredients to achieve that effect. It's kind of the equivalent of deploying a "nuclear" insecticide to your lawn.

The good news, if you decide to apply a curative product this year, is that since you have also applied a preventative product this year, you shouldn't need to apply a curative product this fall or next spring.

What I do is apply a preventative grub treatment every year, because I had grub problems about 5 years ago. I still see some grubs from time to time (the preventative products do not eliminate 100% of grubs), but have not had any problems with grubs damaging the lawn since regularly applying a preventative product.

TimmyG
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Re: Grub Dilemma

Post by TimmyG » May 15th, 2019, 1:54 pm

And then there are pheromone traps for the adults beetles, which you could certainly use in addition to a preventative treatment. I use only traps and have done so for years while keeping my grub population well in check, which it wasn't before I started. I might find a couple grubs when digging a 3-ft hole for a new tree. With the traps, you're protecting not only your lawn but also your landscape plants, avoiding the need for harmful insecticides like Sevin to protect the beetles' favorite snacks. And what I find most beneficial about using traps vs. grub treatment (besides being much cheaper) is that I'm making a significant dent in the neighborhood population, not just my own brood. Yes, the traps pull beetles from well beyond your property lines, but that's a good thing. Just place the traps at the edges of your property, away from shrubs and flower beds.

And then feed the sun-baked beetles to your chickens. ;-)

KBGkicksazz
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Re: Grub Dilemma

Post by KBGkicksazz » May 15th, 2019, 9:16 pm

I’ll just have to trust that the grub preventer is doing it’s job.

I get frogs and grasshoppers around my yard but I don’t have earthworms yet as the loam the builder brought in is only been there a year.

I don’t want to have to nuke the grubs but seeing those mature ones this early in the season was a shock.


KBGkicksazz
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Re: Grub Dilemma

Post by KBGkicksazz » May 16th, 2019, 9:27 am

Last fall I had turkeys go nuts on my lawn going the grubs or whatever insects were in my lawn.

The turkeys did the lawn damage moreso than whatever they were snacking on.
HoosierLawnGnome wrote:
May 15th, 2019, 1:24 pm
Some are ok. It's when you get a dozen per SF you have to worry about it.

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