Vol. 15—1961 - NorthEastern Weed Science Society

490.
Idee1ly these woUld coVer' food org8l1isms, rate. of growth of fishes, their
abundance and effecti'Veness or riproductiOn. As repetition of treatment is
uSU8l~ the' case in' we'edcontrol and the changes in the fauna ms.ybe CtIII1ulnti
ve, the study" should·oo conti'nued tor sewre1 years. Each report should
include a canplete o.m].ysis of the ~ter and the determination 61' the weed
species present to a8s1s,t· the regul~tory agencies in tro.ns~erence ot the results
to the waters. in which they are interested. ' ,
MrectJ,DDPsS' of QheIl},lR§l CgpY:9J.:
Oert~inchemictlls
thnt haw been used in !lewYork do not appear to heve
been too effective.' "For example" Findley Lake' was' 'anexceedingly weedy lake'
with nearly 3/501' its araa in Weedbeds. In lC)S6e program of weed control
wes :tnstit~d. Sodi,. l1rseDite at a ?t p.p.m.d,osege as .1.8;203ws used and
was reported to give good pontrol. !henan yeor the dosage was increased to
10 P.p.m. It was. cle1me4 red ts were slightly better ~ . When it became neces­
8e~to obtain 0. permit, the dosage was cut beck to;?i p.p.m. It waS cla1lned
this failed to control the weeds. In 1959 an application was made for the
use ot pelletized 2,~D8rid8a088ge or 10 lbs. per Pore acid equivalent wss
authorized since thepro~lem w~s p~Uy J.lrri9J?AYllUlli •. Itws8 reported to
the Boord tbot the agent would not gUarantee results at less than 20 Ibs.
The permit wes amended to permit, this do~ageprovided the area treated was
cut in halt. Applicct:1onreportedly ftdledto achieve results t1ftdthe weed
situntion was the worst it ~d ever 'been.
, It has.been reported that low level arsenlc may increase, wed growth and
the same ,for applications of' plant hormones where -the concentrations ore inadequate
to kill t!i& plants. It begins to appear that such trap-tments may increase
growth greatly outside tho treatment zone ei1deven inside, after lethal
concentrations are dissipAted. Increased proliferation of. plant tissue could
so increase the total volume ottissue theteny norinal dosage is inadequate
for control. . ,
For the past two years 'tho Ohnutauquii Lake Assoc1otion has treated ex­
,tensive areas of the lnmwith arsenite. In one area, in one year, 2,4~D was
used. Cceplaints are nowbel.ng received thAt in th6 \D1treated areas the densi
ty of the weeds u.: grenter than it )md ever been previously.
:, .
This poses a question which must be anMred. Is spot treat1neDt tor .
weed control increasing the problem in the areas contiguous? Is' it possible
plants ore de'Vel6p1ng cbemico1 resistAnce? If either is so, further consideration
must be giwn to the authorizption of these chemicals for use where it
is ccn~idered undesir~'ble to allowcOmPlete elimiiu:1tion of weeds.
Pub»c
Heqlth:rmPlica'Y,gp.sl
• • ;':" c ~ .. .r ... "'. t..!:
,Possible etteets on wstersupply hasrecelved lIlUch consideration bY'
~o.lth agencies. 'l'be matter 'or possible residuals in the enimals and tish