Vol. 15—1961 - NorthEastern Weed Science Society

percentage of o~r trAnsmission line rights-of-way s~rayed by gr~un4 crews with
very few acres of brush skipped.. A pump with 6 full floating nylon rollers to
force the spray mixture through the pump is mounted on the truck frame under
the tank and is operated by a power takeoff. The normal operating speed is
500 rpm, and at 20 psi the pump delivers 30 gallons a minute. A pressure
gauge, strainer, And adjustable bypass valve are installed. Since no agitator
is installed in the tank, the bypass connecti~n is used t~ keep the water and
chemicals mixed.
On a lOO-foot right-of-way the truck is driven down one side with the spray
directed to the outside edge of the cl4l')a,redright-of-way. At a pressure of
20 psi ;the effeetive swath is 50 feet wide. We normally enter the right-ofway
and drive until about one-half of the mixture in the tQDk is used or until
some obstacle, such as a fence, crops, or a creek, has reen encountered. The
truck is then turned around, and the other side of the right-of-way is sprayed.
~he truck speed is 2 miles an hour, resulting in the spraying of 6 acres of
brush an hour and the application of 50 gallons of mixture an acre.
Numerous test ~lots were established with the automatic spray nozzle using
different chemicals at various rates. The best mixture for our region appears
to be 2,4,5-T esters and water, applied at the ra~e of 50 gallons an acre,
using 1-1/2 gallons, or 6 pounds, of acid.
--- In an effort to reduce right-of-way maintenance cost further and in order to
keep pace with the growth of TVA's transmissi~n system, a contract was negotiated
with a helic~pter contractor in July 1958 to spray 382 acres. A mixture
of 1 gallon of 2,4,5-T esters, conta.ining 4 pounds of acid, in 4 gallons of
oil was applied at the rate of 5 gallons of mixture an acre. Wewere concerned
about the volatility and drift of the oil; and, since all of this work
was on an experimental basis, about 1/2 of this acreage was sprayed using only
water as a carrier. One gallon of 2,4,5-T esters, containing 4 pounds of
acid, was applied in 4 gallons ~f water an acre.
This spraying was done on rights-of-way in remote mountainous areas, where
spraying by ground crews was almost impossible and the cost was prohibitive.
The mixed species present were dense and ranged from 6 to 20 feet in height,
with the majority averaging between 10 to 20 feet. ~e spraying was done
late in the season; however, we felt that. adequate moisture was in the scil
for continued plant growth to aid in the chemical translocation. In the late
summer, 2 months after application, the susceptible .~pecies were defoliated,
or the leaves had turned brown. Chemical translocation was evident in the
stems ~f tulip poplar, sweet gum, black gum, sumac, .pe~6immon, and sassafras.
We could see very little difference at this time between the reeults of the
spraying with oil as a carrier and those in which ~te~ had been used.
In 1959, after one growing season, it was observed that geod control was
obtained on sweet gum, black gum, tulip poplar,. black locust, wild cherry,
sassafras, sumac, persimmon, and the majority of the eaks; that fair control
'- was obtained -m red. oak, chestnut oak, red;bud, and hickory; and that poor
control was obtained on maple, elm, ash, sou:rwood, pine, and cedar. This
inspection showed that the oil spray had a slight advantage over the water
spray in controlling a few of the more resistant species.