Vol. 16—1962 - NorthEastern Weed Science Society

Because of the lush growth of quackgrass, nutgrass and annual weeds in
some plots, all plots were cultivated with a tractor on May25, June 19 and
August 1. Counts of quackgrass and nut[rass were made in June and September
by taking four one-square-foot samples from each plot. After the ratings were
made in June and July, weeds were removed from all the plots, including controla.
All of the plots were weeded, cultivated and seeded to oats in September.
The nursery plants were evaluated by three persons in August and the new
growth of forsythia was measured in September.
Air temperatures were slightly below normal and rainfall was above normal
in April and Mayof ·1961.
Results
and Discussion
Control of Nutgrass As shown in Table 1, only EFTCat 5 lbs.A controlled
nutgrass appreciably on June 14. At that time nutgrass control was almost
complete with some small and deformed plants remaining. The rating of 9.2
is the better measure of control on June 14, because the counts included
the stunted plants. Had the plots not been weeded and cultivated at that
time perhaps EPTCwould have continued to control rnrtgrass , The ratings on
July 18 and the counts in September show that EPTCno longer was effective.
Although simazine as a fall or post-planting treatment had no effect
on the first crop of nutgrass in the spring, the data clearly indicate a
suppression of the second 'crop of nut.grasa with all of the simazine treatments.
In nursery plantings, where hoeing every three to four weeks is a
rule, arv suppression of nutgrass such as that by simazine would be of
c.efinite value.
The final counts of nutgrass in September indiuate that none of the
herbicide treatments had any lasting effects on the development of nutgr3ss
from tubers. All of the treatments, in fact, had more nutgrass thAn the
oontrols, most likely because the treatments all controlled quackgrass which
appears to suppress nutgrass germination.
COntrol of Quack~rass The data for quackgrass are given in Table 2. Fall
applicat~on of s~zine at 3 oro5 lbs./A, atrazine at 4 lbs./A and propazine
at 4 lbs. provided about 90 percent or better control at all counts and ratings.
Amitrol and dalapon alone were somewhat less effective. The pre-planting
treatment with EPTCprovtded 93 percent control of the first crop of quackgrass
but later evaluations indicated a reduction in control, whereas most
other treatments provided better control at lat&r evaluations.
Although granular simazine alone at 3 lbs./A provided relatively poor
control ef quackgrass, it greatly increased the eff£ctiveness of all treatments
except EPTC. The combination of fall applications of atrazine at
4 lbs./A or simazine at 5 lbs./A with a post-planting treatment of simazine
resulted in almost complete control of quackgrass fbr the season.
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