Vol. 15—1961 - NorthEastern Weed Science Society

539.
A Study of the Effect
of the Weed-Killer,
2, 4-D Aqua Granular on Six Experimental
Plots of Long Pond, DutChess County, N. Y.
Madelene E. Pierce, Vassar College, Poughkeepsie, New York.
The purpose of this study was to compare the results upon six
experimental plots after each had been treated with different
conoentrations of 2, 4-D Aqua Granular. Observations were made
not only of the effect upon the pondweeds, but also of.the effect
upon plankton and the benthic forms. The duration of this
study was from May 25 to September 20, 1960.
Again I wish to thank Mr. John Gould of the New York State
Department of Conservation for his continued encouragement and
practical aid. For the third summer, Mr. Otto Johnson has
graciously given me the use of his boats. The Dow Ohemical
ex­
Company prOVided me with a small grant whioh covered mileage
pense, stUdent help, and the purohase of 2 new pieces of apparatus.
Thanks to this grant, the Zoology Department of Vassar
College did not need to stretch its bUdget so far for me this
year, but it always helped when necessary. The Diamond Alkali
Company prOVided the 2, 4-D Aqua Granular or Crop Rider.
Sinoe the conditions in Loni Pond have been desoribedin
detail (Pierce 1958, 1959, 1960) only a brief comment upon the
plots studied during the summer of 1960 will be made. A series
of six plots (50 X 50 ft.) was staked out along the west shore
with intervals of 25 feet between the plots. The series was
located within the shallow littoral zone (1-3 feet) Which, for
the most part was choked With a dense growth of floating and
submerged pondweeds. The bottom consisted of a deep (oar 1s
length and more) layer of soft mud and deoomposing plants. The
dominant floating plant was N~Phaea odorata, which covered completely
the surface of two plo s. The most abundant submerged
plant was undoubtedly Utricularia purpurea Which formed a thiok
mat over the bottom of the plot. Included in this dense and
tangled mat in scattered patches were, Chara, several speoies
of potamo~etons, and the moss Drepanocladus which formed a
thick bor er very olose to the shore line.
* Pierce, 1958. 12 Ann. Meet .. Northeast. Weed Oontrol Conf.
338-343.
1959. 13 Ann. Meet. Northeast. Weed Control Conf.
310-314.
1960. 14 Ann. Meet. Northeast. Weed Control Conf.
472-475 and 483-487.