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 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 in the presence and absence of pyraclostrobin at VT. Pyraclostrobin was applied alone at VT, and a non-treated control was 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 non-treated control. A split-application of B at V5-V6 fb pyraclostrobin at VT increased yield 0.52 kg 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 non-treated 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^-1should be applied before VT to synergistically increase yield with pyraclostrobin on fine textured soils.