Submitted to: HortScience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2004
Publication Date: 10/1/2004
Citation: Wood, B.W., Reilly, C.C., Nyczepir, A.P. 2004. Mouse-ear of pecan: a nickel deficiency. Hortscience. 39(6):1238-1242. Interpretive Summary: Tree replant problems have become increasingly common in pecan orchards. They have been associated with a growth disorder called "mouse-ear". It has been discovered that a plant deficiency of nickel is the cause of mouse-ear. Nickel application to affected trees provides a means of controlling the problem. This information supports the role of nickel as an essential plant nutrient element and indicates that nickel deficiencies may be far more common in agricultural crops than supposed.
Technical Abstract: Mouse-ear (ME) is a potentially severe anomalous growth disorder affecting pecan [Carya illinoinensis (Wangenh.) K. Koch] trees. It is especially severe in second generation sites throughout much of the Gulf Coast Coastal Plain of the southeastern U.S., but can also occur in potted nursery trees. Orchard and greenhouse studies on trees treated with either Cu or Ni indicated that foliar applied Ni corrects ME. ME symptoms were prevented, in both orchard and greenhouse trees, by a single mid-October foliar spray of Ni (nickel sulfate), whereas non-treated control trees exhibited severe ME. Similarly, post budbreak spring spray applications of Ni to foliage of shoots of orchard trees exhibiting severe ME prevented ME symptoms on subsequent growth, but did not correct morphological distortions of foliage developed prior to Ni treatment. Foliar application of Cu in mid-October to greenhouse seedling trees increased ME severity the following spring. Post budbreak application of Ni to these Cu treated MEed seedling trees prevented ME symptoms in post Ni application growth, but did not alter morphology of foliage exhibiting ME prior to Ni treatment. Thus, high leaf Cu concentrations appear to be capable of disrupting Ni dependent physiological processes. Foliar application of Ni to ME prone trees in mid-October or soon after budbreak, is an effective means of preventing or minimizing ME. These studies indicate that ME in pecan is due to a Ni deficiency at budbreak. It also supports the role of Ni as an essential plant nutrient element.