Anonymous asked in Home & GardenGarden & Landscape · 8 years ago

Using Beneficial Nematodes on lawn after putting Triazicide "Once and Done" Insect Killer?

I had a really bad grub and ant problem. My whole lawn pretty much died. Last week I put out Triazicide Once and Done Insect Killer by Spectracide. I am still having ant problems arround themy foundation, but it seems like the grubs are more under control as my St Augustine has been growing out in new places that had been dead for months. I'm wondering if I can still put out beneficial nematodes even though I put out the bug killer? Does that bug killer kill off the nematodes, or would they still thrive? I'm still seeing june bugs and spiders around to, that's why I'm not sure.


Also, is it safe to use a lot of the bug killer around the yard? like 2 bags?

4 Answers

  • 8 years ago
    Favorite Answer

    I don't think the chemicals would be kind to the nematodes. Most nematicides are organophosphate or carbamate pesticides, probably what you have used with the insecticide. The question is how long with the pesticide remain active in the soil? Once it begins to break down then I'm thinking the nematodes could go down. I'm wondering about nematode application time. Without knowing what grubs are you are attacking and their life cycle in your area, you could be applying the nematodes.....and the insecticides for that the wrong time.

    Some species of grubs at this stage are so large, control with chemicals is best done by hitting them over the head with the container instead of applying to the soil. The grubs are too large to be affected or are entering into pupal stage so they can emerge in their adult form...beetle? Usually control is better when applied with the insects are in their first few instars......young, very young.

    You might what to contact your country Cooperative Extension agent and if they don't know they would consult with the state entomologist who is far more knowledgeable about your specific grub species and life cycles.

    • Login to reply the answers
  • 8 years ago

    Use any insecticide according to the label. Never use more than is recommended. Use only to control pests on label. I would say it is too early to tell whether the insecticide is killing off grubs. You lawn will not have had time to react yet even if you did kill off the grubs. If it is recovering it is because of weather or other conditions. I would not put out nematodes at this time. Read the Triazide label to see if it mentions nematode control. Also read any info on these nematodes and see what under what conditions they should be released. I would not expect to see any June beetle adults at this time of year. The adults fly in the summer months only.

    Edit--Where do you live? In the SE US?? They have a lot of grub problems there but not in other areas of the country where St Augustine is grown. Also St Augustine is a summer grass and usually goes dormant during the winter and is just starting to put on green growth now. Another way to ck for grubs is to take a large one gallon can cut the top and bottom out, place it in the middle of a damaged area. Tap it in a quarter of an inch and fill with water. If you have grubs there they will come to the surface after a few minutes.

    Source(s): forty years experience as an agricultural biologist
    • Login to reply the answers
  • windy
    Lv 4
    3 years ago

    Beneficial Nematodes For Grubs

    • Login to reply the answers
  • 8 years ago

    Don't waste your money on beneficial nematodes after a heavy application of insect killer--nematodes and other soil organisms are much more sensitive to insecticides than higher insects. Don't use more than the recommended application of bug killer.

    I would skip the insecticides altogether. They do a lot of collateral damage to the ecosystem of your yard. The target pests evolve resistance to the pesticide, but their natural enemies don't develop the same resistance. The pests bounce back quicker, and thrive because you've killed off all their natural enemies.

    Pesticides kill off parasitoid wasps before anything else, and these tiny wasps lay their eggs in the eggs and bodies of insect pests. They help control pests before they get out of hand, and any time you use insecticides you wipe them out before putting a dent in the pest population.

    • Login to reply the answers
Still have questions? Get your answers by asking now.