|Container grown pecan tree displaying "mouse ear" symptoms|
|Mouse ear leaf vs. normal pecan leaf|
Mouse ear is a nutritional disorder caused by a lack of the micronutrient, nickel. Nickel is an important component of an enzyme used by pecan trees to transport of nitrogen from the roots to leaves. Nickel deficiency can be prevented by adding a nickel containing fertilizer to the potting media before planting or by making foliar applications of nickel during the growing season. A product called Nickel plus has been developed for use on pecan trees.