Vol. 54—2000 - NorthEastern Weed Science Society

IS TIIERE FOLIAR ABSORPTION
AND S-METOLACHLOR
OF PENDIMETIIALIN
IN CABBAGE
Xu Bin and Robin R. Bellinder I
ABSTRACT
New York State is the largest producer of cabbage for cole slaw in the United States.
A largeportionof cabbageproductioncost is weedcontrol. Herbicideuse is the major
method used by farmers to control weeds in cabbage. However, nutsedge and velvetleaf
are becoming problems in cabbage fields. Nutsedge can be controlled with s­
metolachIor, available to growersunder a Third Party Special Local Need registration,
and is usually applied post transplant. Velvetleaf is not controlled by currently registered
herbicides. The objective of this research was to explore the possibility of applying
pendimethalin POST with s-metoiachior for velvetleaf control in transplanted cabbage.
The experiment was conducted in the greenhouse with day/night tem~atures of25121
·C. Sunlight was supplemented with metal halide lamps (300 ~E m" S-I PPFD) giving a
14-h photoperiod. Cabbage was transplanted (4-5Ivs) into 16.5 cm diameter plastic pots
containinga 1:1(v/v) mixtureofvenniculite andpeat. Herbicideswere appliedwith an
air-driven,single nozzle greenhousetracksprayerthatdelivered290 L/haat 240 kPa. S­
metolachior (0.94, I.88lb ailA), and pendimethalin (0.75, I.5lb ailA) were applied 1-3
days after tranaplanting to single plants. Treatments were applied to soil only (S), leaves
only (L) and soil + leaves (S+L). Following herbicide application, the pots were divided
intotwo identicalgroupsandwereeitherbottomor topwatered. Herbicideinjury(% of
the untreated control) was evaluated 7, 14,21 days after treatment (OAT) using a 0 to
100 scale (0010~ no injury, 100% ~ total plant death). Plants were harvested 21 DAT,
dried,andweightswere recorded.Theexperimentaldesignwas a split-splitplot with
threereplications, and the experiment was repeated twice. Results showed that there was
no significantdifferencebetweenwateringmethods. No foliarinjurywas observedwith
either herbicide when cabbage plants were covered during application (S). When the
leaves were exposed(L. L+8) to s-metolachlor, transitorychlorosisoccurred. In the case
of pendimethalin,leaf exposure(L, L+S) causedseverenecrosison treatedleaves and
malformationof newly emergingones. Cabbageplantswere stuntedby all treatments,
but those where foliage was covered (S) were less so than when foliage was exposed to
the herbicides (L, L+S). Dry weights were not significantly reduced by any treatment
wherefoliage was covered(S). Dryweightswerereducedwhenleaves were exposedto
pendimethalin,butnotwhenexposedto s-metolachlor.This experimentdemonstrated
that both s-metolachlor and pendimethalin applied POST caused foliar injury and
stuntingin cabbage. However,s-metolachlorinjurywas generallytransitorywhile
pendimethalininjurycausedlong-termfoliarmalformationandgrowthreduction.
I Grad.Stud.andProf.,Dept FruitandVegetableScience,CornellUniversity,Ithaca,NY 14953.
124