Evening star., 1951-08-29
PIow and Hoe Give Way
To Chemicals on Forms
Weed Killers Being Applied
To 30 Million Acres in U. S.
By Thomos R. Henry


Chemical weed killers now are being
applied to more than 80 million acres
of American crop land.
Eventually hoe and cultivator may be
only exhibits in museums.
The cost of hoeing cotton, for ex-
ample. now is about $14 an acre. Better
results at keeping down weeds. recent
tests have shown, can be accomplished
with new herbicide for $685. an acre.
This is accomplished with one Of the
pre-emergence weed killers. 1t is sprayed
just after the cotton is planted. Without
injuring the sprouting crop in any way,
1t keeps the soil free Of weeds until the
crop plant has attained good growth.
Another material of the same kind has
proved quite successful in experimental
tests with corn. This type of herbicide is
highly selective. There are q great many
possibilities. The job is to screen them
until one is found which will prevent
the growth OF most common weeds with
out inJuring the crop on which it is
used.
Still other types are the 'translocated
herbicides." Sprayed on the leaves and
stems, they are carried to the roots
by a plants circulation system. This
permanently kills perennial weeds and
bushes. The first of the weed killers,
2,4-d, which was produced during the
war, is "translocated herbicide"
Kills OFF Mesquite.
One notable development now is under
way. The range lands of the Southwest
are being invaded more and more by
mesquite. This bush has ruined thou
sands Of acres Of grazing land. Cutting
it down. or even burning it, did little
good. After cutting, the mesquite growth
the next year often has been worse than
before. Five or six sprouts came where
there was one bush previously.
But translocated herbicide has been
found which effectively kills the mesquite
roots without injuring range grass, and
there now Is fair hope of Kidding the
whole range country Of the obnoxious
bush.
third type is the contact herbicide."
It merely kills the weed growth above
ground and is of value primarily for
ANIMALS. This is the cheapest type of
weed killer and extensive tests are being
made to find chemicals to which par
ticular crop plants are resistant.
a pioneer. At least 20 herbicides al
ready are on the market. They have
been introduced for the most part by
commercial fertilizer manufacturers and
tested extensively by agricultural coll
leges and State experiment stations.
Some of the most far-reaching tests are
being carried out at the Beltsville, Md,
experiment station of the Agriculture
Departments Bureau of Plant Industry.
There also is considerable group of
soil sterilizers now under investigation.
These are intended to rid the soil Of
root pests, such as the nematodes which
cause enormous losses to agriculture
each year.
Chemicals" says DR.. r. M. Salter of
the Bureau Of Plant Industry in re-
port to the American Association for the
Advancement of Science, "are fast be-
coming as important to agriculture as
the plow and the hoe"
Fungus Killer Research.
At the same time. important research
is going on with fungus killers which
may combine the qualities of weed kill
erS. A recent discovery has been that
OF group Of complex organic chemicals
which are much more specific in their
action than any Of the older fungicides
and are often more effective Copper
and sulphur, for instance, control diseases
Of fruit trees but they sometimes cause
considerable injury, per Sc, to both fruit
and leaves. There is far less risk in
using the new organic chemicals Their
use, for example, has increased the Ma
tion's crop of Anjou pears more than
100000 boxes annually.
Most OF these new chemicals, how
ever, still are too expensive for field use
except for high-value crops, such as
tobacco, sugar beets and vegetables.
Even the cheaper ones require an ex-
penditure of about $40 an acre.
A soil fumigant which could be ap-
piled at cost Of $40 an acre probably
would be used extensively for cotton pro-
duction in California, DR.. Salter says.
If the cost could be reduced to $40 an
acre. its use would be economical all
over the Cotton Belt.