Arrested Ear Development in Corn Caused by a Component of Certain Surfactants
2011
Schmitz, Gary L. | Fassler, Nicholas T. | Fellows, Gary M. | Shirley, Amber M. | Chamblee, Rick W. | Finch, C. W. (Charles W.) | Storr, Mark A. | Vassalotti, Paul M. | Klingaman, Troy D. | Thomas, Walter E. | Rathmann, Duane P.
A phenomenon was noted in 2007 in the U.S. corn (Zea mays L.)–producing regions where ears failed to properly develop after postemergence pyraclostrobin {carbamic acid, [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3 yl]methyl]phenyl]methoxy-, methyl ester} applications. Field experiments were conducted in 2008 and 2009 to evaluate the effect of pyraclostrobin, non-ionic surfactant (NIS), alkylphenol ethoxylate (APE), and crop stage on arrested ear (AE) development. Results indicated that pyraclostrobin did not promote AE development and the cause of these malformed corn ears was APE, a common component of NIS which is routinely added to pyraclostrobin applications in corn. Alkylphenol ethoxylate or APE-containing NIS at 0.5% v/v applied to corn at V12 (12 leaf collar stage) and again at V16 (16 leaf collar stage) caused 36 and 21% AE development, respectively, compared to no AE development in the untreated control or when three different pyraclostrobin formulations were applied without additives. In five application timing experiments, pyraclostrobin plus APE-containing NIS caused maximum AE development (10–62%) when applied at the V10 (10 leaf collar) to V14 (14 leaf collar) growth stage. Pyraclostrobin applied alone at any corn growth stage or pyraclostrobin plus NIS applied at V8 (eight leaf collar stage), V18 (18 leaf collar stage), VT (tasseling stage), R1 (silking stage), or R2 (blister stage) did not cause AE development. The risk of AE development under field conditions can be alleviated by removal of APE-containing NIS when pyraclostrobin is applied to corn at growth stages after V8 and before V18.
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