Vol. 15—1961 - NorthEastern Weed Science Society

315.
~UACKGRASS
S. M. Raleigh
CONTROL
The quackgrass control studies reported in this paper were
conducted under very adverse conditions. There were 2.58 inches
of rain from october 22 to October 28. 1959. and 5.85 inches
from May 8 to May 24. 1960. The plots were plowed May 27 but
not planted until June 7. with a total of 7.30 inches or rain
between treatment and planting.
The results given in Table I are rated with 0 given to
fall plowing without chemical treatment and a rating of 10
b'e I ng complete control. No treatments give comp-lete control.
There were 4 replications in each treatment. A strip, 20 feet
wide, in each plot was plowed and another strip was disked on
October 22 before any chemicals were applied. The disking on
October 29, was immediately after the last fall treatment.
Another 20 foot strip was plowed November 13. The spring treatments
were applied May 5 and another 20 feet were plowed that
day. The fall disked area and another 20 foot strip was plowed
May 27, 1960.
Heavy dlsking in the fall was rather effective in controlling
quackgrass without chemical treatment. The quackgrass
roots were all near the surface of the soil. Plowing November
13 was much better than October 22 without chemical treatment.
Amitrol-T (ACP 569) at 4 pounds per acre applied October 29 was
much better than 6 pounds Amitrol-T applied october 22, apparently
because of the slow drizzly rain. Fall treatments plowed
May 5 were generally much better than May 27 plowing. This is
especially true of Atrazine, also Atrazine plowed the day of
treatment in the spring (May 5) was poorer than plots plowed
~'lay 27.
In Table II. the results are given where plots were
logged sprayed May 4. 5. and 6. 1960. when the quackgraas was
4-6 inches tall. also the results are given with Atrazine
applied pre and post emergence to the quackgrass. All plots
were plowed May 27 and planted June 7.
The excessive amount of rain appeared to reduce the
effectiveness of dalapon and ~mitrol-T. The benzac plots were
much poorer than expected. A commercial field near these plots
treated with Amitrol-T at 4 pounds in mid ~pril, plowed and
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1. Professor of Agronomy, Penn state ~niversity.