Foliar Boron and Pyraclostrobin Effects on Corn Yield

Corn (Zea mays L.) response to boron (B) on fine textured soils has had limited research, and no research has evaluated interactions between B and crop protection chemicals such as pyraclostrobin. This research evaluated effects of foliar-applied B at 0.56 kg ha(-1) and pyraclostrobin {carbamic acid, [2,[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy] methyl] phenyl] methoxy-, methyl ester} at 0.11 kg ha(-1) a.i. on yield, tissue B concentration, severity of disease, and grain quality. Field research was conducted at four locations in Northeast Missouri from 2008 to 2010. Boron was applied at V5-V6, V5-V6 followed by (fb) pyraclostrobin at VT, and with or without pyraclostrobin at VT. Pyraclostrobin was applied alone at VT, and a nontreated control was also included. Over the 12 site-years, pyraclostrobin alone at VT increased yield 5% and B at V5-V6 fb pyraclostrobin at VT increased yield 6% compared to the nontreated control. A split-application of B at V5-V6 fb pyraclostrobin at VT increased yield 0.52 Mg ha(-1) compared to B plus pyraclostrobin at VT. Pyraclostrobin increased grain moisture 3 to 7 g kg(-1), decreased starch 1 to 2 g kg(-1), and decreased extractable starch 3 to 4 g kg(-1) concentration compared to the nontreated control. However, no difference in the number of barren stalks, grain with diplodia (Stenocarpella maydis) symptoms, oil, or protein concentrations was detected among treatments. Disease severity was reduced most consistently with B at V5-V6 fb pyraclostrobin or pyraclostrobin alone. Boron at 0.56 kg ha(-1)should be applied before VT to avoid antagonism with pyraclostrobin on fine textured soils.