Household product could be effective weedkiller, government says

[Guest guest]

WEEKLY FARM: Household product could be effective weedkiller, government says

 

PHILIP BRASHER, AP Farm Writer Saturday, July 13, 2002

 

--

 

 

 

(07-13) 10:00 PDT WASHINGTON (AP) --

 

The solution to weeds and insects that bug gardeners as well as farmers could be

in the kitchen cabinet.

 

Agriculture Department scientists say they have shown that vinegar can be an

effective alternative to conventional herbicides for organic farmers and

gardeners.

 

Products as diverse as canola oil, thyme and red pepper already are registered

with the government as pesticides or repellants. Canola oil repels bugs by

altering leaf surfaces or irritating the insects. Thyme can be sprayed on

ornamental plants to kill aphids. Red pepper is registered as an animal

repellant.

 

Household vinegar contains about 5 percent acetic acid, the ingredient that

kills weeds, said Jay Radhakrishnan, the department agronomist who led the

research.

 

" A lot of people tried this in the past but gave up for some reason, " he said.

 

But the research found that at concentrations of 5 percent to 10 percent, the

product will kill all weeds during the first two weeks of life. Older plants

required higher concentrations. Spot spraying of corn fields with a 20 percent

concentration of acetic acid would kill 80 percent to 100 percent of the weeds

without harming the corn.

 

Canada thistle, a particularly tenacious weed, has proven to be one of the most

susceptible to vinegar, Radhakrishnan said.

 

Although vinegar is far from the first natural product to be promoted as a

pesticide, not many have been the subject of a federal study. Another natural

weed killer is corn gluten meal, a byproduct of corn milling that Iowa State

University researchers have shown to be effective in stopping weeds from

germinating.

 

" One of the problems facing the industry is how do we make people aware of these

products? " said Brian Steinwand, a spokesman for the Environmental Protection

Agency's Division of Biopesticides and Pollution Prevention. " There are a lot of

commonly consumed foods that can be used as pesticides. "

 

The EPA created the office during the Clinton administration to promote the use

of pesticides that would be less harmful to people and the environment.

 

Vinegar is sold in some places as an organic herbicide, but it is not in wide

use in commercial farming.

 

Organic farmers generally control weeds by either cultivating their fields,

which breaks up the soil, or by burning them.

 

" You get 90 percent control with cultivation. I don't think they are going to

switch " to vinegar, said Kathleen Delate, an Iowa State University scientist.

" Where it might have more of a market is with small-scale " growers.

 

Vinegar is not nearly as cheap as conventional herbicides. At $65 an acre, the

20 percent version would be cost effective only if used to treat local

infestations in fields, Radhakrishnan said. Conventional herbicides cost far

less.

 

The vinegar lowers the pH of the soil, making it more acidic, but the effect

goes away in several days, he said.

 

The scientists at Agriculture Department's Sustainable Agricultural Systems

Laboratory in Beltsville, Md., are doing additional research with vinegar to see

if it is effective against weed seeds. The researchers bought various

concentrations of vinegar directly from manufacturers.

 

The Iowa State scientists tried using corn meal as a weed killer and found that

it worked. They then discovered it was the gluten, or protein, in the meal that

made it effective. The fine, yellow powder doubles as an organic fertilizer. It

prevents weeds only if they haven't germinated, scientists say.

 

Any product marketed as a pesticide must be cleared by the EPA to ensure its

safety; household vinegar and corn gluten meal are two that have been. But that

does not guarantee the product will work.

 

The EPA checks the effectiveness of pesticides only if they are used to protect

human health, such as to prevent mosquito-borne diseases. Some states regulate

pesticides more closely, but consumers elsewhere are on their own.

 

" We figure the market will take care of the snake oil. You buy something for

pest control and if it doesn't work, you won't buy it again, " said Steinwand.

 

 

 

--

On the Net: EPA's biopesticides office: www.epa.gov/pesticides/biopesticides

Agriculture Department research on vinegar:

www.barc.usda.gov/anri/sasl/vinegar.html

 

Corn gluten: www.gluten.iastate.edu