Vol. 51—1997 - NorthEastern Weed Science Society

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29
EFFECT OF TANK-MIXING BASIS WITH POAST
ON SETHOXYDIM RESISTANT CORN
Bradley A. Majek t
ABSTRACT
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Three se~OXYdim resistant com varieties, Asgrow RV 620, Dekalb DK 592, and Cargill
4450 were trea early postemergence with Poast Plus tank-mixed with Basis, or 2,4-D. The
Poast Plus trea ents were also compared to more traditional treatments that did not include
Poast Plus. herbicides were applied at rates that were consistent with the label and
recommendation for com growers in the mid atlantic states. Preemergence applications of
Topnotch, and stemergence applications of Laddock, Marksman, and Accent did not cause
com injury. 2, -D applied postemergence caused slight but significant injury to all com
varieties. The i 'ury caused by the 2,4-D was typical epinastic response occasionally observed
one to two wee after application. Sethoxydim injury was not observed on any of the resistant
com varieties hen Poast Plus was added to any of the previously discussed herbicide
treatments. Bor er rows separating the plots were planted with a normal variety that was not
sethoxydim resis 1. The lower leaves of the variety that was not sethoxydim resistant in the
border rows wei sprayed and the plants exhibited moderate sethoxydim injury. Tank-mixing
Basis with Poast Ius applied early postemergence caused injury to the three sethoxydim resistant
com varieties. ,ymptoms included stunting, whitening of new leaves, and some twisting and
buggy whipping lof new growth. The injury was similar to the injury observed on the variety
that was not sethpxydim resistant and received a directed application of Poast Plus in the border
rows. Further research is needed to investigate the interaction observed between sethoxydim and
rimsulfuron and,for thifensulfuron, the two components of Basis. Additionally, the possibility
of interactions ith other sulfonyl urea herbicides needs to be pursued.
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'Bxtension ~pecialist in Weed Science, Rutgers-The State University, Bridgeton, NJ 08302-
9452 I
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