Vol. 15—1961 - NorthEastern Weed Science Society

58.
. .R. D. &wet' and Joseph Cia).one
])epal'tmen;t of Vegetah1e crops, Cor~ University, Ithaca, N. Y.
. *
Although cmc-.:(2-ehloroaU71
diethyld1~iocarbsmate) -has found considerable
'Isage on ve$8tablecrops in Eastern United States, it bas not reached
its fuU potential as a select1ve herbicide because of its errstic performance.
elSC somet:t.mes faUB to control, Weds, and 1ft,' certain situations ~ injure
the crop.. For best, performance _it is genere.U:y agreed that CDBCshould be
applied' at planting and that ,~1gation should be given if rain does not occur
soon after treating. In spite of these precautions, the performance ot cmc
under t1~d conditions baa b4itenvariable. ~ purpose ot these investigations
was to determine JIOre spec1t1ca1.ly the factors 1ntluenciDg C:r:£Cactivity under
field conditions in order to avoid failures due to either crop injury or lack
of weed kill. .
Revd.ewof Literature
'!'he activity of herbicides applied to the soU are known to be 1nf1uenced
by marq, env1roD1lleutal and soll factors. Obtaining COIIIIIlerCia11Y acceptable
veed control without crop inJury:trOll the proJer dosage at a presl:lD8bly selective
soll .herbicide is a function ot the total influence of emtirol'.llDel1t and
soil on the herbicide, on tbte veedJJ, and on the crop. The 1ntluencing factors
most often. mentioned in CODDectton,nth the activity of cmc are rainfall, soU
type, aDd timing. Temperature and formulation are also cited.
Dardelson (1957) stated that cmc perto~ poorly with lov soU moisture.
Irrigat::t11g great17 eDhanced·weed control. !bwver, delayed applications following
rains were poor. He 'concluded the optimum procedure was to apply at
time of seeding" and to irrigate if rains were not soon forthcoming. He did
not suggest re$So~" tOl" t~ .Y~14b1e peri'01'lDal)ceat CDICunder variations in
soU moisture conditions. It was further suagestedthat somewhat higher rates
were needed in SUllllel" than 1n the coolert1me of the year.- Be also studied
fQl'lllulationa and ~eported that 'ary granular carriers such as-vermiculite and
attaclq wereas effective aaliquid formula'tions.
otten (1957) reported 01'1 the persistence and movement of ODICin soils.
He stated that both temperature and moisture were important factors influencing
the loss of activity. His results also clearly showed that although CIIBCcould
be leached, it vas rather difficult to move appreciable quantities downward
from surface applications. This vas true even nth two inches of water on a
Dunkirk sand which contained less than l~ organic matter and less than 4~ clay
and sUt combined. lbvever I more CDECvas leached with a given amount of water,
if the chemical was added to a wt soil rather than to a dry' soU. He concluded
that microbial action vas important in rapid loss of activity at CDECunder
field conditions.
YPaper JJo. 451 of Department of Vegetable Crops.
Sold as Vegedex by ltbnsanto Chemical Co.