Vol. 16—1962 - NorthEastern Weed Science Society

In contrast to the damage noted in EJ.ba from applying either CDAAor CDEC
at planting, itI Oswego CDAAwas not toxic at any t:l.llle of appJ.ication. C~,
however, gave some damage at all thx'ee times of application, with the crook
stage being most severe. A heavy shower followed the crook stage application.
It is believed to be the cause of damage, just as in the first application at
Elba.
At both EJ.ba and Oswego combipations of CDAAand CIPC followed the general
pattern of CDAAalone with respect to both crop response and timing. This is to
be expected because experience bas shown onions in the early stages to be much
more tolerant of CIPC than of CDAA.
CDAA-tlrCBC (Randox T) was similar in per:(ormance to CDAAat both locations.'
Treatment at the flag stage generally gave less CrQP inJury than, did treatments
at other times. Much of the data Obtained follow the CDAAresponse. It is .
difficult to evaluate the effect of TCBCsince this, chemical was not appJ.ied
separately.
At both locations, weed control (see table 4) was best at the last two applications.
This probably was due to several factors. First, in the periodl)etween
planting and the third time of treatment, temperatures were quite low and weed
development slow. In this same period rainfall was heavy and soil fixation and
other forces were active which tend to reduce the effectiveness of herbicides.
Later with higher temperatures when weed activity did reach its maximum, many
of the chemicals were probably below their maximumlevel of activity.
!a£.l~ ~._ ~!.s!.~_C~n~r~l_a~d_w~i~ ~f_w~e!!sJ~~v~d_b;r, !!a~d.L ~uq3.L Q.s~~o:.. _
!,t ]!.a~t!n~ £r2.0~ ~t~! :El!g_S~8§.l!
Chemical lbs/ 1bs. lbs. lbs.
!r~t _']l~n~ __ A__ !!.e~d~ _ ~u!.s!.an~ W~e!!s_ .Jl~~~n~ __ y~e!!s__ ~U!.s!.~e_
105
CDEC
CDAA
6
6
19.33
14.96
1
2
CDEC 4 15.33 1
CDAA 4 10.40 3
CDEC+CDAA4+2 9.20 2
CDEC+CDAA3+3
CDEC+CDAA2+4
5.10
16.23
3
2
CDEC+CDAA4+4 11. 40 3
CIPC 4 29.20 2
CIPC 6 29.83 1
CDAA+CIPC 6+4 8.65 6
CDAA+CIPC 6+6 11.25* 7*
CDAA+TCBC4+10 6.33 9
CDAA+TCBC6+15 ,5.03 . 9
CK 34.97 3 "
1P oory -two -replicates. - - - - - - -
9.36
6.46
9
2
6.53
4.53
7
2
15.76 6 22.40 7
8.0 3 8.2 5
7.06 4 10.07 4
5.30 6 6.63 6
5.70* 5* 6.96 5
4.46 6 2.93 6
24.36 2 26.30 2
21.30 1 14.93 1
3.30 7 3.16 7
6.60 6 4.36 7
3.10 9 4.10 9
1.46 '9 1.03
__ 3!!:,.2,7 3 3~.2,7
'9
:1 _
At both locations regardless of timing CDAAgave more effective weed control
than did CDEC. Where the two chemicals were in combination at Oswego both
the 4+4 and 3+3 lb. rates gave effective weed control regardless of timing.
The 4+2 and 2+4 combinations of CDAA+CDEC were not consistent in weed control
performance.