Vol. 15—1961 - NorthEastern Weed Science Society

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306.
c) Seedling toleranqe trials
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XF-832: Seedling bent, blue and, rye grasses 'Were not injured
when treated with .3/4or l~ Ib/lOOO sq ..ft., 3 or 6 weeks after
seeding" Fescue and clover were injured somewhat at both rates.
14hile this chamical is intended as a pre-emergence crabgrass
material, it caused a significant reduction in the stand of
crabgrass llhen applied post-emergence to seedling crabgrass in
the 2-leaf (1 inch) stage. Control was a1lllost complete at the
Ii lb/lOOO sq. ft. rate.
XF-834: Seedling fescue and clover were slightly affected but
bent, blue and rye grass were not injured by either rate o This
chemical had greater post-emergence activity than Al'1A.-41on
seedling crabgrass, controlling crabgrass completely at both
rates and times of application.
XF-833: This was the most selective chemical of the three having
practically no effect on turf grasses and clover. It was slightly
less effective post-emergence on seedling crabgrass.
Zytron 1328 and 1481: The dry form (1.481) produced slight injury
onbent, blue ana fescue, while the liquid form (1328) produced
considerable injury.
Chlordane (product): This material produced no significant injury
ort'seed::i.Ing turf grasses or clover.
Dacthol (product): This material produced only very slight injury,
iiiCSt"Ol'it in the early treatment.
Conclusions
Based on 1960 fleld tests, it is apparent that XF-832, w:i.thin the
range of rates tested, most nearly achieves the objectives stated at the beginning
of this paper. ' '
Zytron and Dacthol, tlhile offering excellent pre-emergence crabgrass
control and satisfactory turf tolerance, have the disadvantage 'of preventing
growth of turfgrass seeds planted within four weeks ,after application of these
chemicals.