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How do pyrethroids work?

Discussion in 'Pesticide & Herbicide Application' started by whoopassonthebluegrass, Jul 19, 2008.

  1. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Posts: 4,214

    Bifenthrin, permethrin, deltamethrin, etc...

    I read the facts. I get that they're an axonic poison that keeps the sodium channels open in the neuronal membranes... which leads to paralysis... (wikipedia...)

    Here's my question: how does the chemical transfer to the insects brains? How does simply walking on the chemical get it into the insect's body? I NEED to understand this, b/c I believe it's key to why some bugs die readily enough, while others aren't seemingly affected at all...
  2. Ric

    Ric LawnSite Fanatic
    Posts: 11,956

  3. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Posts: 4,214

    Ric:This explains how the chemicals KILL. I know that already. I want to understand how the chemicals translocate through the pest to the brain. Is it actually absorbed through the feet? Is it rubbed across spiracles? Is it cleaning themselves with their poison-coated legs? Etc.

    I google first. I try to avoid looking ********... as uphill a battle as that may be...
  4. Ric

    Ric LawnSite Fanatic
    Posts: 11,956

    OK I didn't read the site, only did a fast Google to avoid Typing. Different Insecticide have different modes of Action and different ways of contaminating the target. Pyrethroids are ingested and also adsorbed by the Exoskeleton But they don't have to travel all the way to the brain. Pyrethroids stop nerves from firing so the brain sends a signal but the body doesn't receive it. Kind of like cutting a wire and your tail light doesn't work but the battery is still good. Therefore causing Heart and Respiratory function to cease. Permethrin works the quickest but has little persistence's Bifenthrin is a little slower but has longer Persistence's
  5. PHS

    PHS LawnSite Senior Member
    Posts: 724

    Whoopass, I think "cleaning themselves" is a way they can ingest materials. The cleaning is to clean off the chemoreceptors that are located on different parts of the insects body. Those receptors get covered with other substances which interfere with proper function so they have to clean them constantly.

    I suppose materials could enter their nervous system directly through those chemoreceptors as well. Their are tons of them all over their feet. Insects don't "look" for food per se. As they're walking along if they step in food that's edible for them, those sensors fire and if it needs food it starts eating. In a simplistc way that's how it works.
  6. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Posts: 4,214

    Very informative, thank you.

    As I consider this, I think of insects that don't die when on the chemicals. Boxelder Bugs are this way. People will spend big money to kill them, but I'm often reticent to spray b/c I've seen over ands over again that, unless I spray them directly, the residual chems don't do a darned thing.

    Any speculation as to why some seem immune, vs others?
  7. LawnTamer

    LawnTamer LawnSite Gold Member
    Posts: 3,988

    Not that this answers your question, but I know you have Paintbrush lane to do still, so you should be out working anyway.

    Back in the day when OrganoPhosphates, (OPs) were plentiful, I would use them on Box Elder bugs, very effective. Malathion would always make short work of them. It is interesting because OPs are also nerve toxins. I have had good knockdown of BoxElder bugs with Orthene too.
  8. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Posts: 4,214

    Just got back from that BS...

    But did you get a residual? I can kill them directly with no trouble. I just want to see something that I can spray across someone's entire house and actually have it deter the little buggers for more than the 30 minutes till it's dry...

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