ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
EFFECT OF CALCIUM SPRAYS ON CONTROL OF BLACK END, FRUIT QUALITY, YIELD AND MINERAL COMPOSITION OF 'BARTLETT' PEARS |
| Author: | J.T. Raese |
| Abstract:
Bearing 'Bartlett' ('Williams') pear trees, (Pyrus communis, L.), having a high proportion of the trees in an orchard affected with the fruit disorder, black end (hard end), were selected for the experiment. In the initial phase of the study, the trees were observed each year for those consistently having black end and for trees always void of the disorder to establish and assign experimental treatments in the orchard. Those trees having black end fruit consistently had low Ca, Mg and Mn but high N and P concentrations in the fruit when compared with normal fruit from the same trees. Calcium chloride (CaCl2) sprays applied six times each of four seasons from mid-May to late July increased fruit and leaf Ca concentrations, reduced the incidence of black end by 25 to 68 percent, lowered the development of senescent scald and internal browning and increased fruit firmness. Calcium-boron sprays increased leaf and fruit B concentrations, reduced the incidence of black end and senescent scald development, and increased fruit firmness and total acids. Trees having no black end fruit disorder had higher concentrations of leaf Ca, Cu and Mn and larger fruit than black end-affected trees. | |
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