Vol. 15—1961 - NorthEastern Weed Science Society

394.
RESULTS§e PISCUSSION
In August of 1959 or 1960 the plots were rated as to percent control
of the crabgrass. The results are reported in Table 1 for all materials
except the various Calcium Arsenate compounds.
No treatment resulted in serious turf injury except the Pax at location
A. Here the bluegrass was noticably thinned out. Pax also caused
some turf thinning at location B. Granular Zytron at 20 Ibl A also caused
slight turf injury at locations C & D, as did nNo-Crab" at location D.
There was considerable variation between the various calcium arsenate
compounds. They also varied widely from one location to another. For
example, "No-Crab" resulted in 98'l control at location D, and 441. at location
E. In general, control was fairly good with the calcium arsenate materials.
Table 1. Late Summer Control of crabgrass with Various Pre-emergence Herbicides
-_ ..._..._--_ ..._.... -----_ ...---_ ...-.-------- ....-----
Tmt. Rate Av. Fall
I/A A C Tmts. B D E Av. Spring Av.
% Control Tmts.
--------~-_ ... _----_.._------.... ------------
Chlordane
10% 75 62 12 37 78 55 65 66 54
" 20% 60 27 20 24 30 25 30 28 26
" 75% 75
-­
40 55 23 39 42
Zytron-e.c. 15
-­
67 85 78 . 77 77
" " 20 89 85 84 91 81 81
It gran. 15
--
83
" " 20 13 -­ 70 95 83 83 83
72 99 85 85 82
Daethal, w.p. 5 48 20 34 83 10 75 76 14
50
-­ -­ .79
tI II
10 70 68 69 88 93 96 92 83
PAX 1080 87 -­ 80 85 83 84
Untreated CIt 0 0 0 0 0 0 0 0
------------_ ..._----------------- ......._---­
Locations A and C were treated in the fall or early winter; the others
were late March treatments. The Ohlordane treatments were somewhat more
successful when applied in the spring than when applied in the fall. The
same was even more true of the 8aethal treatments.
Over-all, the eblordane treatments were the least' successful. Deethal,
Zytron lie Pax resulted in good crabgrass control. Little difference was
found between the granular & the spray forma of Zytron. Daethal lie Zytron
treatments were more successful than Pax, in that Pax injured the turf ..