Symptomatology and etiology of pear yellow. Correction through ferrous sulfate injections

Jaime R. Montealegre A.1, Jaime Auger S.1 y Antonio Rustom J.1

The research was performed, from 1982 to 1985, in an orchard located in the Metropolitan Region, Chile. Diseased trees exhibited less development, scarce foliage and severe chlorosis, on some or all the branches. The leaves, generally, were smaller and yellow and in some cases, with apical necrosis. Highly affected branches showed cortical necrosis, with insufficient growth, and death. It was determined that this problem was caused by iron deficiency, according to symptomatology, graft transmission tests, electron microscopy studies, and the response to injections with antibiotics and with Fe, Mg and Zn products. Best correction treatments were injecting 1 to 2 It/tree of FeSO4, in 1.7,2.0, and 2.85% concentrations. Some of the treatments showed a small phytotoxicity, that was recoverable.

1 Departamento de Sanidad Vegetal, Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile.