Grub insecticide harmful to Earthworms?

Recently I repaired section of my lawn by removing the soil and placing new soil and seed. I took note that I didn't see a single earthworm. I feel this is odd and not healthy... In my research I have learned to treat the lawn for grub prevention in Fall for best results. Is it possible that my grub prevention efforts in the past killed beneficial critters like earthworms?

5 Answers

  • 1 decade ago
    Favourite answer

    What insecticide did you use for grub control? Imidacloprid (Merit) is a common active ingredient used for the control of grubs for over ten years and has shown no impact on earthworms. Copper fungicides are organic yet copper in the soil is death to earthworms. It all depends on what you use. Not all pesticides kill earthworms and not all organic or home remedies are safe for worms.

    In the future, consider the use of nematodes that target white grubs. They are natural, safe (except for white grubs), and last for more than one season. Milky spore is also an effective natural control for Japanese Beetle grubs. Unfortunately milky spore will not affect other annual white grubs.

    I know that Scotts does a good job of marketing the need for yearly grub control applications, but this is seldom the truth for the average homeowner. Good Integrated Pest Management teaches that you should scout first and only apply pesticides when economic or aesthetic thresholds are exceeded. For grubs that means that if you have a density of annual white grubs that exceed 10-12 per square foot, you should consider control. Below this number and your lawn grows faster than the damage created by grubs so no pesticide application is really needed.

    "Earthworms are generally susceptible to carbamate compounds, which will significantly reduce their populations. Carbaryl, a carbamate pesticide often used for insect control, acts as a cholinesterase inhibitor, thereby producing long-lasting immobility and rigidity. Bendiocarb (Turcam) and propoxure (Baygon) are two other carbamate insecticides that cause paralysis in earthworms at normal dose rates. Carbofuran, another carbamate, is also very toxic to earthworms. Moreover, a sublethal response, characterized by weight loss, delayed clitellum development, and absence of cocoon production, has also been observed at recommended rates of carbofuran application.

    Organophosphates are the most widely used class of turf insecticides. They have been successful in controlling white grubs, mole crickets, chinch bugs, and sod webworms, to name a few. Of the organophosphates, ethoprop is the most toxic to earthworms. In contrast, chlorpyrifos, isofenphos, and trichlorfon are considered non-toxic to earthworms when applied at normal dose rates."

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  • Anonymous
    4 years ago

    For the best answers, search on this site

    The moles are being attracted to your yard because there is a food source. Most likely, that source is grubs, weevil larvae, and other types of worms. The first thing you need to do is get rid of your creepy crawlie problems. While you could apply lots of chemical insecticides, these cause problems environmentally, and to children and pets. If you truly want to be humane to not only the moles but those around you, you can use beneficial nematodes. Nematodes are microscopic worms that parasitize grubs, weevil larvae, and other harmful worms (note: they don't affect earthworms, which are very good for your lawn and would be killed by insecticides). In terms of application, you want to apply them to moist grass later in the day (4 -7 pm) and make sure that they stay moist for as long as possible. But, you do not want to irrigate or have rain because that is too much water. Instead, what I do is sprinkle the area with the shower mode on my hose's spray nozzle. The nematodes will provide not only quick results, but lasting results. They will work as long as you keep the conditions right. If you happen to have a drought or something, then you would need to reapply and start the process again. There are a number of companies that sell nematode products, but many are not worth wasting your money on. I have tried many different ones and found that the best ones are distributed by Becker Underwood in Ames, IA. They ship them overnight to you and because of how they package them, the packs are still cold (before applying, it is important that the nematodes remain cool -- most other companies don't take that much care). While they do not sell them to your common joe, you can call them and they will tell you where the nearest retailer to you is. The type that you will probably need is "Heterorhabditis bacteriophora" and it is marketed at Nemasys G. Good luck! (By the way, if worse comes to worse and you need to get rid of the moles, you can put unwrapped sticks of Juicy Fruit gum in their holes. They eat it, they get bound up, and they die. I've have never used that because I have always used the nematodes, but my grandma used to have great success with it when I was a kid.)

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  • 4 years ago

    Lawn Grub Killer

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  • 1 decade ago

    Oh yeah... Stay away from those nasty chemicals.

    Next time, use Milky Spore or beneficial nematodes. Both are organic and kill those grubs without hurting beneficial critters

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  • 1 decade ago

    Sorry to hear that, general insect/side will kill many things,try and buy a enviromentally friendly product

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