Vol. 16—1962 - NorthEastern Weed Science Society

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WKEDOONTRQI, IN. TRANSPIANTEll O~l ,
S. 'L. Da~ and R. L. sa;q.;;ti:' ,
""
Blght years .,when tranaplanted_et Spanish type
oniQl1$weretiret groll1'1on eastern:~ Island, the main weed pests were,,,
ohiokweed and puss1ey~ Some orabgrass and barnyara-gi-ass would oome in .l&~r
in the season 'bv.t presented no signifioant ,probl,~ Four Pounds per, ~ore:' ',,
of OIPOapplied in direQted sprKyS at apprOXimately three: week interTa1s', '>
togethllr with a relatively smal~ allDunt of hand weeding,g~ve growers good
seasonal control. " '. .
ChangeS have: occurred during the past three to four
years which have requil'ed a rs-&y.aluation of our--eerUerresults. ElrC&l~t·"
weed oontrol is still adhieved up until June 20-25: when the grasses begirt"
to ell18rge. Th1-"date of emergenpe is apparently at least a week earlier, .'
than :1t used t.Obe, possibly bec~use of higher soU tsmpe;rature due to llic'k
of :weedoover, and in addi;tion, J.coentuated by a IIIljIchhigher infestation pf
grass seed. The grass problem, particularly barn;y-.rd, hall multiplied man1i'old.
With PIPO pro'Vi,ding little if ant,oolllllElroial cont~l, growers have had to ."
use oonaidezoable hand labor to k~thei1' fieldsFeHeMbly ol~through ,
harVest.' , ' , ",' , ' ,
Methods. . The two majot'varieties grown ~ EarlY Harvest and
SWeet,Spanish,' and though the latter is deoreasirli:in importanoe'the weed
problem in it is greater beca~e,,.t matures later. Seasonal and layby
exper1Jllents wereoonduoteli,therW:OI'e, on both.,,A,lthough OIPCis still _:liisfaotory
through IIDst of June, it,~s felt that other materials should be',',
tried to determine if the,y woutd:provide better early oontrol of germinat~
IftSs. This in tarn would allow 1&ter appl:icationof SOmelayby' materials
known to be effective against gra,ssbut injurious to onions if applied too
earJ:9'.· , " .. ' ,',' '
Early Harvest~ transplants Weresei in the field APr:l.~ 12,
treated May 8, .JUne1.3, July 5, J(1ly 28, and harvested August 8; Sweet Spanish
were set April 25, treated May 1$, June 1.3, July 5 end '26, and harvested
August 17. Theherbioides were applied with a t'WO-llOw,uaotorlllOunted "
sprayer and directed towards the base of the plants. Prior to each application
all plots were rated, and established weeds re1iPved .;.- by hand in the
rows and shallow oultivation between ron. 0"', '" '
Onions used in the layby experiments were treated at
three week intervals during the first part of the growing season with OIPC.
All plots were clean cultivated and weeded before the layby treatnrants were
applied -- June 29 on Early Harvest, July 18 on Sweet Spanish. The liquid
fomulations were handled as described above; the granulars were applied
directly over the row and the foliage brushed with a trailing rope.
Additional experinrants were conduoted in cooperation with a commercial grower
where the grass problem was much more severe than on the Researoh Farm.
The Early Harvest test, the only one reported here, was applied June 28 and
July 6, and the crop harvested August 10.