Available alternative products, non-glyphosate based products rarely generate 100% weed control. They perform better on broadleaf weeds than grassy weeds. They are best used in conjunction with optimizing cultural practices such as improving soil health, turf/plant nutrition, irrigation, cultivar election, proper moving, and seeding/plant establishment and overseeding. Avoiding conditions that favor weeds (compacted soils, overwatering, excessive or ill-timed nitrogen applications) and adjusting soil pH to favor desirable plants over weeds increased effectiveness. Most alternative herbicide products are not chemicals, so they are exempt from EPA pesticide registration.
Alternative herbicides fall into 7 product categories: Natural acids (vinegar + citric acids), Herbicidal soaps, Iron-based herbicides, Salt-based herbicides, phytotoxic oils (clove, peppermint, pine, citronella), corn gluten, and combination products (including ingredients from multiple categories).
Alternative herbicides may not be regarded as long term single application herbicides like glyphosate, but as short term “burn-down” products. An initial germination treatment followed by spot treatments later in the season is necessary to minimize persisting perennial weeds. A single application once (or twice) a year is not sufficient to keep “trim” areas (pavement, sidewalk cracks, skin surfaces on playing fields, etc) weed free. Moreover, the cost of alternative products may be higher compared to glyphosate:
higher per application and more applications per year , resulting in higher labor expenses. Alternative herbicides also require higher volumes of water, higher volume pumps and larger nozzles on sprayers.
Ways to improve effectiveness when using alternative herbicides include:
•Thorough spray coverage (to runoff); A large, flat nozzle (ie. 8006) is preferable in turfgrass production
•Add the high label amount of surfactant/adjuvant to improve control
•Treat when weeds are small (2-5 leaves)
•Repeat applications for larger weeds are necessary in most instances.
•Lower concentrations at high spray volumes (i.e. 10% concentration in 70 gallons per acre) appear to be more effective than high concentrations at low spray volumes (i.e.20% concentration in 35 gallons per acre).
From an economical perspective, alternative herbicides cost more than chemical herbicides due to the concentrations and number of applications required. For example, a lawn study in NY found that acetic acid herbicides were more than three times more costly on a square foot basis than glyphosate.
Another study by the U. Mass Transportation Center, showed that glyphosate cost ~$20/mile to control weeds along roadways. They also found that alternative materials (Citric Acid, Acetic Acid, Clove Oil, Scythe® , etc) varied in cost from $360 to $2400 per mile.
Vinegar – Acetic acid, commonly known as vinegar, but also known as ethanoic acid, affects the cell membranes of a plant, causing rapid breakdown/desiccation of foliage tissue on contact.
Herbicidal vinegar is stronger than household vinegar, the acetic acid concentration for herbicidal use is 10 -20%, compared to 5% (household) acetic acid. Acetic acids of 8% or less inert ingredient are exempt from registration by the EPA as a pesticide under EPA Minimum Risk Pesticide, FIFRA. Most states require registration for use of acetic acid as a pesticide.
•Excellent control when contacting very small annual broadleaf weeds
•Rapid kill rate (Over 90% of treated plants should die within 24 hours).
•Acetic acid products break down quickly in the environment.
•Most useful for managing weeds in gravel and on patios/sidewalks.
•These contact herbicides fit into an integrated pest management program; although weeds require monitoring for best control timing.
•Non selective, but mainly kill broadleaf weeds. Burns back grasses temporarily.
•No residual activity. Will kill or damage any plants they touch.
•Weeds must be small (timing is important – within 2 weeks of germination)
•Roots are not killed; repeat applications are needed for larger weeds and perennial weeds
•Good spray coverage is essential (70 GPA+)
•Sharp vinegar odor may be unpleasant
•Spray equipment must be cleaned after application, particularly metal equipment. Avoid using spray equipment with metal working parts such as metal spray lines or metal nozzles.
•Spray drift may damage desirable plants.
•Do not apply to reactive metals such as aluminum, tin, iron, and items such as fencing or lawn furniture. Avoid spraying the material onto masonry sidewalks and structures. If the product contacts these surfaces, staining, mottling, etching, or other harm to the finishes or surfaces may occur.
•Do not apply more frequently than every two weeks
•Treatments must be delayed 24-48 hours or more after rain
•Severe eye irritation, burns, and possible irreversible damage potential. Vinegars with acetic acid concentrations of 11% or greater can burn the skin and cause severe eye injury, including blindness.
•Severe skin irritation and possible allergic sensitization.
•Prolonged or repeated exposure may cause dermatitis, chronic bronchitis, and erosion of teeth.
Research has found that 5-10% acetic acid herbicide products can give viable control of very small, young weeds that have only 1-2 leaves (or within 2 weeks of germination). Larger weeds (with 3-4 leaves) are likely to survive treatment, but using higher (20%) concentrations of acetic acid and increasing the application volume (from 20 to 100 gpa) can improve weed control. Total crabgrass and grass weed control in a 2006 USDA study occurred with 20% acetic acid applied at 100 gpa, resulting in weed control that ranged from 28 to 45%. Multiple applications improve long term control. Broadleaf and annual weeds tend to be more susceptible than grassy weeds and perennial weeds, which show initial signs of damage but generally recover. Nonetheless, using acetic acid on weeds with tap roots (dandelions, Canada thistle), may only result in top kill unless the weed is very young.
COMMERCIALLY AVAILABLE ACETIC ACID PRODUCTS
Check with your state to determine if a product is registered to be used as a pesticide.
Bradfield Natural Horticultural Vinegar – 20% vinegar (acetic acid) + yucca extract. (Bradfield
Organics) NOT OMRI Listed Burn-out – 25% acetic acid (St. Gabriel Laboratories).
Grotek Elimaweed Weed And Grass Killer – 7.15% acetic acid (GREENSTAR PLANT PRODUCTS)
Maestro Gro’s Organic Vinegar. 20% acetic acid (Ag Organics/Nature’s Wisdom) 1 gal %15.79
Natural Weed Control – 0.2% citric acid, 8% acetic acid + water. (Nature’s Wisdom/Ag Organics).
Soil Mender 10% Vinegar – 10% acetic acid (made from grain alcohol and not from glacial acetic acid), orange oil, molasses, and a natural surfactant.
Vinagreen Natural Non Selective Herbicide- 20% acetic acid (CMC Chemical)
Weed Pharm Fast Acting Weed And Grass Killer – 20% vinegar (acetic acid) (PharmSolutions.
Things you may or may not know about Glyphosate
Glyphosate was patented by Monsanto under the trade name ‘RoundUp’ in 1974. Glyphosate is now widely available from many manufacturers under numerous trade names after patent protection ended in 2000: RoundUp, KleenUp, Accord, Imitator, Eraser, Pronto, Rodeo, etc.. There are over 750 products containing glyphosate for sale in the U.S according to the National Pesticide Information Center.
As a non-selective herbicide, glyphosate will kill most plants it contacts. Accordingly, it can be used for vegetation cleanup prior to all types of planting, e.g. field/bed/turfgrass preparation or renovation. It can be spot sprayed for general weed control or sprayed directly over top of specific crops at certain times of year (e.g. over Christmas trees/conifers in the fall). No other herbicide works as well on perennial grasses as glyphosate particularly late in the season.
Glyphosate does not leach through soil like some herbicides and has low mammalian toxicity, it has been considered to be very safe toxicologically and environmentally, with hundreds of studies showing the active ingredient to be less acutely toxic than common table salt or aspirin.
The EPA does not consider glyphosate to be a human carcinogen.
If you have a problem with the Glyphosate information above, take your concerns to the USDA, FDA, EPA or Monsanto
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