Despite the long chemical and strange botanical names, there are a lot of products available today that are considered biorational. This means they are compatible with, or have little impact on, biological organisms. They can be useful for treating a spot flare-up with a short blast or two without sacrificing the entire biological program. Biorational pesticides, if used with care, can be an effective tool to the biocontrol practitioner. Learn more about pesticides in an integrated pest management (IPM) program, and consider our most recent feelings on the matter.
On these pages you’ll find…
Bacterial Controls
Bacillus thuringiensis or Bt
Bacillus thuringiensis [(Bt) BAH-sil-us-thur-inn-gee-en-SIS] is a pathogenic, bacterium-based, microbial insecticide which targets a specific individual or group of organisms. It is most commonly known for its use as a caterpillar pest control. Here’s some background followed by some of the more common varieties:
Some Bt Background
Bt is named after the German town of Thuringia where it was discovered in 1911 in diseased flour moths. Since that time, 35 other strains have been identified. Each strain attacks specific target organisms. Commercial marketing of Bt began in 1958 with variety kurstaki.
Bt, a substance consisting of spores and protein crystals, is a stomach poison which must be ingested by the target organism in order to be effective. Upon ingestion, the spore, which comes into contact with the highly basic (alkaline pH>7) gastric liquids and potent enzymes inside the stomach of the pest, begins to breakdown. When the spore breaks down, it exposes the protein crystal. The crystal neutralizes the enzymes which serve to protect the stomach lining of the pest from its own digestive juices. When the protective juices are neutralized, the digestive juices begin to eat holes through the target organism’s stomach wall. The stomach’s contents enter the affected organism’s body cavity and blood steam. At this point, all feeding stops — the target organism is no longer a destructive pest. This poisoning of the blood, known as septicemia, may also cause paralysis. The cessation of feeding happens in as little as a few hours post-ingestion, and biolysis or dissolution of the pest will occur in just a few days — it gets yucky. After death, the bacteria inside the host will continue to parthenogenetically reproduce in the subsequent generations — Bt is a onetime killer.
The primary, and most popular, target organisms for which Bt is used, are the destructive larvae of several moths and butterflies: caterpillars. Caterpillars affected by Bt will normally darken and hang downward at an angle of 90 from the branch to which their prolegs (pseudolegs used to support and aid mobility to their massive larval bodies) are attached.
Bt is very specific to the pest for which it is intended and labeled. In laboratory tests, toxicity in mammals and nontarget organisms is virtually nil. Therefore, Bt’s use in biocontrol or integrated pest management (IPM) program is highly recommended if the target pest, for which the formula is labeled, is one requiring control. Please note, however, that some formulations — those with a petroleum base or other adjuvant used as a spreader-sticker or surfactant, etc. — may be lethal to nontarget organisms such as some beneficials. Caution should be exercised if the possibility of physical contact with nontarget organisms exists.
Dipel 10G Sweet Corn Granules Bt var. kurstaki (Bt-k)
This strain comes in one formulation: as Sweet Corn Granules. It is used and labeled for the control of the European corn borer and tobacco budworm. Dipel 10G is a granular formulation which is used as a bait. The target organisms for which this bait is intended find it irresistible, much more than the host plants, in fact. This old, classic variety and formulation is widely used and very popular among growers of corn and tobacco.
Apply directly to corn whorls when 25% of whorls show shot hole feeding for a 1st generation kill. For a 2nd generation kill, apply when 35% of whorls show feeding. Use 0.5-1 oz. per 272 sq. ft. or 5-10 pounds per acre, depending on target pest. Repeat applications as needed.
Dipel 150 Dust Bt Berliner (BtB)
The Dipel 150 dust is used and labeled for the control of cabbage loopers, imported cabbageworms, grape leafrollers, and tobacco and tomato hornworms.
Apply when the pests are first noticed. Use 0.25-4ozs. per 435 sq. ft. or 12-50 pounds per acre, depending on target pest. Repeat applications every 4-10 days, as needed.
You may purchase Bt 150 Dust online now!
Dipel .86 WP Wettable Powder Bt Berliner (BtB)
Dipel .86W.P. wettable powder is used and labeled for the control of cabbage loopers, diamondback moth larvae, Gypsy moth larvae, elm spanworms, inch worms, leaf folders, sod webworms, tobacco and tomato hornworms, and tomato fruitworms.
Apply when the pests are first noticed. Use 1-8 tablespoons per gallon of water. Use 2-10 gallons per acre. Rates vary according to crop and target pest. Repeat applications every 4-10 days, as needed.
You may purchase Dt .86 Wettable Powder online now!
Bt Liquid Concentrate Bt Berliner (BtB)
BtB Liquid Concentrate. liquid concentrate is used and labeled for the control of alfalfa catepillars, cabbage loopers, fruit tree rollers, grape leafrollers, Gypsy moth larvae, imported cabbage worms, omnivorous leafrollers, orange dogs, red-humped caterpillars, rind worm complex, and tobacco and tomato hornworms.
Apply when the pests are first noticed. Use 1-4 tablespoons per gallon of water. 1oz. treats 680 sq. ft., or 0.25-2 qts. per acre, depending on the target pest. Repeat applications every 7-14 days, as needed. Warning: product contains oil.
You may purchase Bt Liquid Concentrate online now!
Colorado Potato Beetle Beater
This strain comes in one formulation: a liquid concentrate. It is used and labeled for the control of Colorado potato beetle larvae and elm leaf beetle larvae and adults. It is commonly called the “Colorado potato beetle beater.”
Apply at the very first sign on larval presence. Use 1.5ozs. per gallon of water. 1oz. treats 1000 sq. ft. Repeat applications every 4-10 days, as needed.
Important Notice: This product has been changed by the manufacturer (without notice). It now contains spinosad. We either be adding this info to this site or discontinuing this product altogether. We will let you know as soon as we can.
You may purchase Colorado Potato Beetle Beater online now!
Bti Mosquito Dunks var. israelensis
There is one stable formulation of this variety: a compressed briquette — Mosquito Dunks. Mosquito Dunks are used and labeled for the control of mosquito larvae. These BtBi briquettes may be used anywhere there is standing, stagnant water: puddles, birdbaths, swampy areas, etc.
These briquettes can even be used in vernal pools (pools, puddles, etc., which dry out between rainstorms — mosquitoes exploit these sites, too. Mosquitoes lay eggs in vernal pools, and when it rains, the eggs hatch. Mosquito Dunks work in vernal pools because they remain effective indefinitely when dry. However, as soon as they get wet, they are reactivated. If they dry out again, they can be stored again, and that cycle may be continued until the briquette is completely dissolved.
This is easy-to-use product which is very effective. For even better mosquito control, also try enticing bats to live on your property by placing bat houses.
Apply 1 briquette per 100 sq. ft. of standing water, regardless of its depth. Briquettes may be broken into pieces for smaller pools. Repeat applications every 4 weeks or so, as needed or when briquettes dissolve completely.
You may purchase Bti Mosquito Dunks online now!
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