Vol. 15—1961 - NorthEastern Weed Science Society

287.
Halts F-24, Halts F-26, Halts l"-29, and halts F-20a produced more than 95
ryercent control. The two remaining Halts formulations, F-25 and F-2b gave 88
and.82 percent control respectively. Only F-24 produced any discoloration and
it was slight.,
1'
! .
, '
. "Th~ crabgrass 'Olants in our plots were not as a~gressive as would be expected
in a lawn area that received supplementary water. August was a dry month
which aggravated this condition. The results are not compromised, however, becmtse
the iridividual crabgrass plants were picked out of the square foot quadrats
and control was based on comparison with the check plots.
Summary~ Conclusion
1-13489, L-31864, Lacthal, Zytron, tricalcium arsenate, calcium arsenate,
Halts (F-24, '-26, F-29, F-20a) gave a highly significant degree of control
without discoloration or injury to the basic turf.
halts F-25, halts F-2b, Ct~ordane, and Chlordane + ~~L~ resulted in 88%to
75% control which is highly significant but hardly satisfactory on the basis of
crabgrass plants per square foot.
rates
Niagara 5996 and Ohlordane CS-201 did not give significant control at the
used.
1-34314 showed no selectivity; injuring the basic grasses as severely as
the crabgrass.
Acknowledgment
Jl~preciation is extended to ~li ~illy and Co. for sup~ort in conducting this
research program.