Treatment for Mouse-Eared Pecan Trees Now
August 30, 2007
A foliar fertilizer developed by
Agricultural Research Service (ARS)
scientists to alleviate the condition known as "mouse-ear" in pecan
trees has been licensed to NIPAN, LLC,
of Valdosta, Ga. NIPAN will produce the nickel-based treatment under the trade
name NICKEL PLUS. Mouse-ear reduces pecan trees' health and size, makes the
trees' limbs brittle, and shrinks nut yields.
The mouse-ear abnormality shows itself as rounded or blunt-tipped leaves.
Previously recognized as "little leaf," it's becoming increasingly
common in second-generation orchards when pecan trees are replanted. It can
also occur in other trees, such as river birch. One treatment of NICKEL PLUS,
sprayed on foliage about two weeks after budbreak, is usually sufficient to
correct the disorder.
ARS plant pathologist
Wood, research leader at the
Fruit and Tree Nut Research Laboratory in Byron, Ga., determined nickel
deficiency to be the cause of mouse-ear. They observed a lack of nickel uptake
by affected trees, even when there was an abundance of nickel in the soil. They
found that even a severe case of mouse-ear could be corrected by a timely
foliar application of nickel liganosulfonate.
Heavy metals such as zinc, manganese, iron, cobalt and copper compete with
nickel for uptake channels in the feeder roots of the pecan tree. Additionally,
lighter metals such as calcium and magnesium also act to indirectly limit
nickel uptake. The researchers found that nickel deficiency had usually been
induced by excessive soil or plant accumulation of other elements due to
decades of fertilizer applications.
Wood assisted with determining the liquid formulation for NICKEL PLUS, which
was developed by NIPAN, LLC. The formulation has now been approved by several
state departments of agriculture as a fertilizer for correcting nickel
The severe form of mouse-ear most commonly occurs in the southeastern
Georgia sector of the U.S. pecan belt, but is also found throughout much of the
Gulf Coast coastal plain.
ARS is the USDA's chief scientific