Vol. 15—1961 - NorthEastern Weed Science Society

535.
On AUVlst 15, 1960, tht first of tnrf;c trcatmonts
wns made to a 23 aero rus0rvoir filled with Eloden,canadensis.
Trcatm0nt was ~ede at four dny intervals to minimize the
possibil~ty of fish kill anrl undesirablo odors. Control was
ostimated at 95%. No undesirable odors or tastes were exhibited.
There was no fish kill. '
SILVEX ~ TreetmJnt was made on July 27, 1960 at
tho rate of 0.5 ppm. Control of Myriophyllu~ hcterophyllum was
excellent and estimated at 100%. Floating forms, however, showed
only slight control at this rate. The species and the degree of
control were as follows: Nymphaen sp., 70%; Nuphar sp., 30%;
Brasenia sp., 30%. There was considerable regrowth of these
latter forms noted in September when the areas were resurveyod.
GRANULARFORMULATIONS
ENDOTHAL 5% QRANULAR: On June 30, two 1.0 acre plots
were treated at tho rate of 2.0 ppm. The species an~ degree
of control were as follows: Potamogeton natans 90%; Potamoguton_
Robbinsii 100%; Nvmphaea sp., 60%; Nuphar sp.,40%; Utricularia
sp., 60% and Polygonum sp., 30%.
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ESTERON 99 (2,4-D): Treatment was m~de to 1.0 acre
and 2.5 acre plots on June 27 and July 27 respectively. Application
at th~ rates of 50 lbs/acrc proLucerl results as follows:
MYriophvllumh~tcrophy~lum 100%; Nymphaea ap., 80%; NuphQ£ sp.,
60%; ££ratophyllun eem;rsum 70%; Potarnogcton natans, no results.
M-1847 (SILVEX): A 5.0 acre area was treated on
.Iunr. 29, 1960 att1k rate of 50 lbs/acrc. Granular salt of
Silvcx pro~uc~d excellont results in clcaring the area of tho
following forns: liYm,phaca sp.,lOO%; Nuphl'r sp., 100%;
Ccratophyllurn cemcrsum 100%; Utricularin purpurca 80%.
sn,MZI~~ 4G: \nlilc only one test was concucted
this mrterial, an( that being only 0.75 acro in size, it
wns felt however that the results against Piblyr;on1.!E
pcnnsylv.;:.nicum were somowh.ct significant. Control of this
species was estimotcd at 80% of the original population.
with
DISCUSSION:
Field studios of tho various herbicides tested indicate
clearly that some formulations are more effective in dealing
with one nqudtic'wcod problem thnn another. It is also
significant to point out that no one chOt"lical was effective
against all s~ccics of aquatic vegotation treated.