Influence of different calcium materials and spray timing on mineral composition, yield, fruit quality, and control of fruit disorders of ‘anjou’ pears

Abstract

Abstract During a six‐year period (1980, 1985–1989), 20 different calcium (Ca) materials were sprayed at an early (3X; June to July), late (3X; July to August), and an early plus late (5X; June to August) timing on 25‐year‐old ‘Anjou’ pear (Pyrus communis L.) trees. Calcium chloride (CaCl2) sprays increased fruit Ca in the cortex by an average of 10.5% greater than in unsprayed controls and cork spot was reduced by an average of six‐fold. Yield from trees sprayed with Ca materials averaged greater than 13% more crop load than the unsprayed control trees. Leaf and fruit injury from CaCl2 sprays in 1980 were near borderline acceptability, but injury was reduced slightly by halving the spray concentration rate to 681 g CaCl2 per 379 liters of water in 1985 to 1989. Due to temperatures above 26°C, leaf and fruit injury from Ca sprays, particularly calcium nitrate [Ca(NO3)2], were more severe for the late or early plus late sprays than for the early sprays. Fruit size was slightly larger on trees sprayed only ...