Vol. 15—1961 - NorthEastern Weed Science Society

529.
As an algicide we have been using 2,3-Dichloronaphthoquinone (Phygon
XL). This is a selective algicide and will not produce, in our opinion, the
clarity of water that copper sulphate does, Within the fish kill liniits.
There are certain well established critical temperatures of fresh water that
stimulate certain species of algae into activity. We watch for 68 degrees
Fahrenheit and 77 degrees Fahrenheit. However, we are not attempting to
destroy all algae, as we try to run off as much as possible in suspension.
Moreover it protects our fish life. Our costs for algae treatment l~re formerly
higher than the cost for weed treatment. Now algae control expenditures
are one-third of the present cost of weed treatment. We must advise that
we have to face up to some complaints about algae following the weed kill,
but there is an understanding acceptance, in view of the overall objective.
The dichlone is applied by the same equipment as the sodium arsenite
with minor changes. We mix fifty pounds of the powder with one hundred gallons
of lorater. The liquid is drawn from the tank by a twenty gallon per
minute pump. A "y" connection is used to direct one outlet approXimately 45
degrees off the port stem and the other 45 degrees off the starboard stern.
To produce a spray pattern two short lengths of ordinary garden hose with
adjustable nozzles are used. An effective mix is obtained ,men the spray
pattern just meets the outer edges of the propeller wash. We use one pound
per acre. Control and constant agitation is obtained by adjusting a by-pass
valve directing a percentage of flow-back to the tank.
As possibly related to our algae growth, a comment on our coliform
count is interesting. Considering the potential possibilities we have of
coliforn contamination, we are unusually low. We are told by a local
bacteriologist; who does our analytical work in this category, that we have
the ,lowest average coliform count of all northern New Jersey lakes that come
under his observation - also the highest algae count. This possible relationship
is supported by a paper presented at the American Public Health
Association on November 3rd at San Francisco, entitled II Controlled Photosynthesis
and Public Health ll , and the National Civic Review July, 1900.
The rapid production of oxygen by algae acts as one of natures most powerful
purifying agents. This is another reason why we have put limits on our
algae kill.
lVithin the boundaries of the Lake Mohawk reservation, we have a
twenty-four acre pond known as Upper Mohawk. This pond is also infected
with Potamogeton. crisp~s • Our treatment in this pond is the same as on the
main .Lake , For sqme reason the plants grow at Upper Lake with less vigor
and develop about three weeks later. In 1958 this pond was infected lrl.th
Myriophyllum ·spicatum. It spread with great rapidity. By August, 1958, the
growth could be seen under water throughout the entire t,,,enty-four acres.
On August 20, 1958, we treated with 2,4,5-TP (Kuron) at 2 PPM; The chemical
was mixed with fifty percent water in a one hundred gallon tank and was constantly·
agitated by power. Application was ~de with an ordinary adjustable
garden hose nozzle under light pressure. Every square foot was treated. The
shore linea were simultaneously treated with a hand pump from a rowboat. The
Myriophyllum was literally nipped in the bud. No evidence of this growth has
re-appeared up to 1900. To prove this control, we elim1n.a.ted all treatment
of either sodium arsenite or 2,4,5-TP in 1959. The 2,4,5-TP applied in
August, 1958 also sharply lessened the Potamogeton growth in 1959. lIowever,