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WB01343_.gif (599 bytes)  Pesticide and Environmental Update

U.S. Town Uses Hot Water to Control Weeds

See Our Weed Control Strategies Page


  Carrboro, North Carolina, is killing weeds with water instead of
chemicals. The town is using a machine that superheats water and
dispenses it in a carefully controlled stream to kill weeds without using
toxic chemical herbicides. The equipment, which is made in New
Zealand, is in use in several other countries but is almost unknown in
the United States.

Carrboro is testing the equipment to implement the town's least toxic
Integrated Pest Management policy, adopted in March 1999. The policy
calls for phasing out use of conventional pesticides, including
herbicides, on town property, but does not apply to the local residents,
their property or businesses. City leaders hope to show how beautiful
grounds can be achieved without poisoning the environment.

To date, efforts to reduce pesticide use have emphasized alternatives to
conventional herbicides. An earlier analysis of Carrboro's pest
management practices showed that more pesticides were used on weeds
than for any other purpose. Weeds are a problem around buildings and
parking lots, along curbs and gutters and in parks. The town is using a
comprehensive approach, rather seeking a single solution, including a
biodegradable herbicide made from corn gluten, propane flamers which
kill plants by singing them, thick mulch on plant beds to smother
weeds, and now hot water.

The machine in use in Carrboro produces a steady stream of near-
boiling water that kills weeds by melting the waxy outer coating of
their leaves. The self-contained machine is mounted on a small truck
with hoses connected to long-handled applicator wands. A quick spray
on unwanted weeds kills them; the plants darken almost immediately
and turn brown within a few hours. The flow of water is low and cools
quickly. While the results look very much like that of a contact
herbicide, there is no toxic residue and the area is immediately safe for

"That's what it is all about," said Allen Spalt, Director of the
Agricultural Resources Center and a member of the Carrboro Board of
Aldermen. "We want to find ways to reduce pesticide use so that we
can eliminate the risk of any child being poisoned. Carrboro already
uses only small amounts of pesticides; we believe that this hot water
system may be part of the solution to reducing use completely."

The hot water system, on loan to Carrboro until the end of June, will be
used by town staff, who will also demonstrate it for other interested
parties. At the conclusion of the trials, a final decision will be made
whether or not the town will purchase the equipment.

Source/contact: Allen Spalt, Director, Agricultural Resources Center,
PESTicide EDucation project, 115 West Main Street, Carrboro, North
Carolina 27510; phone (919) 967-1886; fax (919) 933-4465; email:; Web site

Pesticide Action Network North America (PANNA)
49 Powell St., Suite 500, San Francisco, CA 94102 USA
Phone: (415) 981-1771
Fax: (415) 981-1991