Beneficial Microorganisms as a pesticide

Discussion in 'Organic Lawn Care' started by ICT Bill, Feb 21, 2008.

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    Here is some information that I have gathered, most of it is cut and paste from articles I have found
    The question on another thread was whether there were certain types of Bt that harmed good guy animals like butterflies and moths.

    Some commercially available Bt varieties and target pests:

    Bacillus thuringiensis
    var. tenebrionis - Colorado potato beetle and elm leaf beetle larvae
    var. kurstaki - caterpillars
    var. israelensis - mosquito, black fly, and fungus gnat larvae
    var. aizawai - wax moth larvae and various caterpillars, especially the diamondback moth caterpillar

    Mode of Action
    The toxic crystal Bt protein in commercial formulations is only effective when eaten by insects with a specific (usually alkaline) gut pH and the specific gut membrane structures required to bind the toxin. Not only must the insect have the correct physiology and be at a susceptible stage of development, but the bacterium must be eaten in sufficient quantity. When ingested by a susceptible insect, the protein toxin damages the gut lining, leading to gut paralysis. Affected insects stop feeding and die from the combined effects of starvation and tissue damage. Bt spores do not usually spread to other insects or cause disease outbreaks on their own as occurs with many pathogens.

    Bacillus thurengiensis isreali Bti, most often sold as a hard donut, fights mosquitoes when placed in standing water. And is a bacteria that is toxic to mosquito larvae. The bacteria causes the stomach lining of mosquito larvae to rupture and ultimately killing the mosquito larvae.

    Bt is used to kill caterpillars before they have a chance to pupate into winged adults,

    Bacillus thuringiensis kurstaki (B.t.k.) is a naturally occurring bacteria found in the soil. An inactive, or spore, form of the bacteria is approved by the Environmental Protection Agency (EPA) for use as a pesticide to control the gypsy moth. B.t.k is commonly used by organic gardeners and is approved for use on more than 200 food and grain crops in the U.S. Over 100 million pounds are used each year in the U.S.

    B.t.k. is harmful to moths and butterflies that are in their caterpillar stage. Caterpillars that eat B.t.k. on trees and shrubs die when the B.t.k. spores are activated in the insects' stomachs.
  2. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    Does anyone use these regularly for their lawn program?

    Is Milky Spore the same thing, I think it is a different strain. Same effect though I believe
  3. NattyLawn

    NattyLawn LawnSite Bronze Member
    Messages: 1,643

    We use BT's on the tree side, not lawn.
  4. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,160

    Milky Spore is Bacillus popillae-Dutky. The mode of action is completely different as when grubs eat it, the spores reproduce in the grub and when the grub dies, billions of spores are released into the soil and continue to infect more grubs. It is limited to controlling only Jap beetle grubs.

    Bt does not reproduce and spread to kill more caterpillars. But it's still pretty cool for a soil microbe. :cool2:
  5. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,160

    Forgot to mention Bt controls armyworms, cut worms and sod webworms.
  6. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    Are you saying that Bt needs to find a host (grub or whatever) or it becomes part of the soil biomass? Basically croaks and is food for something else

    It doesn't just hang out for years and wait for a host to populate?

    It seems "the host" or pest depends on the species that is being applied
  7. treegal1

    treegal1 LawnSite Gold Member
    Messages: 3,911

    ????????? wasent BT bacillus thurgensus ; hope I stuck that one; originaly found in the bahmas or jamaca in a compost pile of sugar cane crush. do I have any of this rite

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