Vol. 15—1961 - NorthEastern Weed Science Society

1
CHEMICAL QVACKGRASS CONTROL
Jonas Vengris 2
This is a progress report of work done in 1959/60 with herbicides
for quackgrass (Agropyron repens) control.
Amherst.Mass.
Experiment:
Trials were conducted on a fine sandy loam with fair drainase. The
experimental area had a good uniform stand of quackgrass.It was also
infested with nutgrass (Cyperus, esculentus); however, the stand of nu~grass
was not too uniform. Plots were 12x'25 feet in size. Two repl1cat~, were
used. In the fall of 1959 treatments were applied on October)5 on-4; lush
8 inch growth of quackgrass. In the fall treatments, dalapon, atr~~ne
and simazine were used. In all tables, rates are expressed as acid equivalent
or active ingredient per acre. Five days after the application of
herbicides, the experimental area was irrigated with 3/4 in. of water.
By December 3, quackgrass plants treated with dalapon andatrazine
were stunted and chlorotic. Simazine was less effective. On May 6, following,
quackgrass stands were again surveyed. The results are shown in,
Table I. In general all treatments were effective in suppressing quackQrass.
Spring treatments ofdalapon and Fenac were applied on April 28 on
8 in. growth of quackgrass. On May 16 the whole experimental area was
plowed, disked, fertilized and the seedbed prepared for planting corn.
EPTAM,Atrazine and Simazine were applied as spring treatments on May 20.
Three days later, May 23, Ohio M-15, silage field corn was planted. On
some treatments (Table I), the applied herbicides were immediately it.ked
in 4-6 in. deep. The followiog night 1/2 in. of rain fell. To control
annual weeds, the whole experimental erea was treated on June 2 with
3 lb/A of DNBP. No cultivation was done. Quackgrass stand estimates were
made on July 28 and again on September 15 (Table I) following corn harvest.
The treatments applied in the fall of 1959 gave excellent quackgrass
control with Atrazine being the most effective. There was little observable
difference between the different rates used. During the growing
season all the fall treatment~ became infested with nutgrass. The lush
growth of nutgrass suppres8e~ quackgrass and thus indirectly increased
the effectiveness offall treatments in controlling quackgrass. No one
herbicide applied in the fall significantly controlled ~~ut -grass. Of
the spring treatments, the best qu&ckgrass control was obtained with
Atrazine. Mixing the applied Atrazine immediately with the soil slightly
increased its effectiveness. The best nutgrass control was obtained with
both rates of EPTAMand Atrazine, end the poorest with dalapon and Feoac.
Corn was slightly stunted by Fenlltc and 6 Ib/A of EPTAM. Later on
corn in these plots regained normal growth.
1. Contribution No. 1283 of the University of Massachusetts a College of
Agriculture, Experiment Station, Amherst a Massachusetts.
-- 2. Assistant Professor of Agronomya University of Massachusetts. Amherst.
Massachusetts.