Pecans. Click image for additional photo
Nickel Deficiency Causes Pecan Tree Disease
August 27, 2003
Pecan trees that don't absorb enough nickel from the soil are prone to a
disease, called mouse-ear, that causes abnormal tree growth and development,
Agricultural Research Service scientists
in Byron, Ga., have discovered.
Scientists Bruce Wood, Charles Reilly and Andrew Nyczepir at the ARS
Fruit and Tree Nut Research Laboratory in Byron found that other heavy
metals such as zinc, cadmium and copper compete with nickel for uptake channels
in the feeder roots of the pecan tree. That may help explain why the
researchers found mouse-ear disease in trees growing in nickel-abundant soil.
A severe case of mouse-ear is corrected by a timely foliar application
of nickel. The severe form of mouse-ear most commonly occurs in the southern
Georgia sector of the U.S. pecan belt, but is also found throughout much of the
Gulf Coast Coastal Plain.
Mouse-ear first appears on early spring shoot growth. It can
consistently reappear from year to year, or appear only occasionally, on the
same trees. Its occurrence is often spotty, and highly variable within affected
trees and orchards.
The scientists used two treatment strategies in their studies. In one,
they treated foliage in October with nickel sprays. In the other, they treated
foliage shortly after bud break in the spring. In both cases, the foliar spray
applications of nickel corrected mouse-ear. Fifty trees were treated in the
fall, 200 trees in the spring. In every case, nickel sprays corrected
Agricultural Commodity Commission for Pecan, and the Partners in Production
granting program of the Southeastern Pecan Growers Association, helped fund the
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.