Foliar chlorosis in field-grown red maples

Franksred red maple (Acer rubrum 'Franksred') trees were sampled from nursery fields in 2003 and 2004 to determine the cause of a common foliar chlorosis. Plots in 21 and 39 different nurseries were identified in 2003 and 2004, respectively. A single plot from each nursery was sampled in June of each year, whereas two to four plots per nursery were sampled in September. Each plot consisted of 20 consecutive trees in a single row. From each plot, a foliar tissue sample was analyzed for the complete range of essential nutrients. Plant height, stem diameter, leaf chlorophyll content, and a subjective plant quality rating were also recorded. From each plot, a soil sample was collected and analyzed for pH, EC, organic matter, and a range of essential nutrients. The foliar chlorosis was determined to be incited by manganese (Mn) deficiency. Tissue Mn was highly correlated with soil pH. Chlorotic plants were smaller with less stem diameter than nonchlorotic plants. Sufficiency ranges for tissue and soil tests were determined and are provided for red maple nursery production.