Technical Abstract: Most U.S. pecan orchards would benefit from one or two annual applications of Ni as a foliar spray. Such sprays should be applied at Ni rates of 25 to 100 ppm, depending on degree of Ni deficiency. Sprays can be applied in early spring within about 10 days after bud break or, in the case of severe deficiency, in the autumn. Autumn treatment ensures Ni is present in buds at time of spring bud break. Most orchards are thought to experience chronic (hidden hunger) Ni deficiencies. Acute deficiencies (those showing visual symptoms) are relative few, but the number is increasing as soils accumulate metals that reduce Ni uptake by plants (i.e., Zn, Cu, Ca, and Mg).