Proceedings of the Sixty-first Annual Meeting of the Northeastern ...

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HOT WATER SYSTEMS FOR VEGETATION MANAGEMENT. R.G. Prostak and A.V.
Barker, Univ. of Massachusetts, Amherst.
ABSTRACT
In recent years, the requests from the general public for non-chemical weed
management strategies have increased. Two experiments were conducted at
University of Massachusetts Crop Research and Education Center in Deerfield, MA to
evaluate and compare two hot-water, weed-control systems.
The AQUACIDE Environmental Weed Control System Model 665 by E.C.O.
Systems Inc. delivers 5.6 gpm of super-heated hot water on demand at an operating
temperature from 232 to 253 o F. Four types of wand-end applicators are available. The
Waipuna Organic Hot Foam Weed Control System by Waipuna Systems Ltd of
Auckland, New Zealand delivers 3.1 to 3.6 gpm of hot foam at an operating temperature
from 203 to 208 o F. A plant sugar extract from corn and coconut is mixed with water at
0.4% v/v to produce the foam. Three types of wand-end applicators are available for
the Waipuna. Both systems heat water with a number 2 oil burner.
Experiment 1 was treated was treated on June 13, 2006. Four by twenty foot
plots were treated with each machine at 1, 2, 3, or 4 minutes. Control of vegetation was
assessed at 2, 17, 30, and 43 days after treatment (DAT). Experiment 2 was treated on
July 11, 2006. Four by twenty foot plots were treated with each machine at 3, 3.5, 4.5,
5.25, 6, or 7 minutes. Control was assessed taken at 2, 15, 20, 35, and 52 DAT. The
test site was a mixed stand of tall fescue (Festuca arundinacea Schreb.), quackgrass
(Elytrigia repens Nevski), sweet vernalgrass (Anthoxanthum odoratum L.), orchardgrass
(Dactylis glomerata L.), and timothy (Phleum pretense L.).
The Aquacide and Waipuna machines provided similar levels of control at a
given time interval treatment in each experiment. In experiment 1, Aquacide or
Waipuna treatments at 2, 3, or 4 minutes resulted in mean control of 88% at 2 DAT, and
the 1 minute treatment provided 69% control. At 43 DAT, mean control decreased to
10% at 1-minute time of treatment, 14% at 2 minutes, 24% at 3 minutes, and 42% at 4
minutes. In experiment 2, all treatments resulted in a mean of 98% control at 2 DAT and
80% control at 20 DAT. Percent control decreased to 41% at 35 DAT and 3% at 52
DAT. Control of vegetation by hot-water treatment lasts for about 5 weeks, and choice
of implement may be based on convenience and costs of operation.
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