Corn Yield Response to Pyraclostrobin with Foliar Fertilizers

Strobilurin fungicides, including pyraclostrobin, protect many crops from several fungal pathogens and create opportunities to increase plant health and yields. However, corn (Zea mays L.) and many other plants’ physiological responses to pyraclostrobin include increases in processes that require nutrients. By applying foliar fertilizers, growers can adjust their nutrient-management strategy based on the plant’s reaction to pyraclostrobin. Identifying plants’ increased nutrient demands and meeting them with a foliar fertilizer at the time of fungicide application (tasselling) could increase yields. This study evaluated effects of foliar-applied pyraclostrobin at 0.11 kg ha-1 a.i. with or without 13 commonly available foliar fertilizers on yield, tissue macro- and micronutrient concentrations, severity of disease, and grain quality. Field research occurred at three University of Missouri research centers from 2008-2009. One foliar fertilizer, 0-0-30-0, caused up to 20% crop injury. Diseases affected plants in all six site-years, but overall severity was low (≤ 2%) and likely did not impact crop performance. Pyraclostrobin increased ear leaf B and Cu concentrations over all site-years seven days after treatment, and decreased N concentrations at one site-year. Grain yields increased 5% at two research sites with pyraclostrobin, and one location had increased grain moisture and grain oil at harvest. One foliar fertilizer, 30-0-0-0, increased grain yields by 10% at two sites compared to the non-treated control. However, foliar fertilizers showed no observable effects on grain quality characteristics, and none of the foliar fertilizers negatively impacted grain yield.