Vol. 15—1961 - NorthEastern Weed Science Society

,veedone at 4 pounds of tL.cl per acre gave 98%control of crabgrass, with
slight discoloration after the first application, and slight to moderate discoloration
after the two later applications. ht the 6 pound rate, 99%control
was achieved, and ~uite severe discoloration occurred after the third application.
Clout gave 87%and 99%control at 2.83 and 5.66 pouzds of D}~ per acre,
respectively. Only slight discoloration resulted from either rate.
Sodium arsenite at 0.75 pound of As 2 0 3 per acre did not control crabgrass
in this,·tes.t, and caused slight discoloration of the turf.
291.
Cacodylic acid at 0.5 pound per acre gave no control, and resulted in mod­
to severe discoloration.
erate
PM2, 4-L applied at 0.8 pound per acre failed to adequately control crabgrass.
I':oderate discoloration was observed after the last two applications.
F\l 734 at 0.5 pound and 1 pound did not control crabgrass significantly and
the highest rate caused slight discoloration.
test.
Void at 4.12 pounds of ~}~ per acre produced inadequate control in this
At the end of the experiment, no permanent injury was noted from any of the
treatments. It was observed that each plot which showed adequate control also
contained little or no clover. The plots receiving the I-pound rate of FW734
also contained little or no clover.
After the second application, severe chlorosis of dandelion plants was
observed in the plots receiving SD 6623 at 2 pounds per acre with repeated
treatments and also in those receiving the single a~plications of 4 and 6
pounds with a wetting agent added.
Injury to chic~yeed occurred in plots treated with 8L 6623 at 2 pounds per
acre a9ulied twice, and with all the higher application rates of this material.
Similar inhibition of chickweed was observed after the second application in
plots receiving the following materials: Limet + 2, ~tox, iJeedone (at both 4
and 6 pounds), sodium arsenite, P}i 2, 4-L, and ~v 734 at 1 poUId per acre.
sm-iHAhY ~D CONCUJSIONS
;
Post-emergence crabgrass control tests were conducted at the University of
Khode Island during the summer of 1960. :t-Jaterials used which gave a highly significant
measure of control were:
1. Dimet + 2 at 3.4 pounds of .AMh.and 0.73 pound of 2, 4-L per acre - 95%
control.
2. Artox at 4 pounds of ~~ per acre - 100%control.