Manganese Deficiency in Pecan

Abstract

A low leaf Mn concentration was detected in bearing pecan ( Carya illinoinensis Wangenh. C. Koch) trees growing in an alluvial soil with an alkaline pH. Trees lacked vigor and leaves were pale in color, but there was no discernible leaf chlorosis or necrosis. Three foliar applications of MnSO 4 beginning at budbreak, then twice more at 3-week intervals at rates of 0 to 3.3 kg·ha -1 of Mn increased leaf Mn concentration curvilinearly, and alleviated leaf symptoms. Results indicated that three foliar applications of MnSO 4 at 2.15 kg·ha -1 of Mn plus a surfactant were adequate to correct the deficiency.