The influence of mineral nutrition on the susceptibility of apple trees to infection by Trametes (Polystictus) versicolor

Abstract

Trametes (Polysticus) versicolor is shown to be highly pathogenic to apple trees grown in sand culture with a nutrient deficient in phosphorus. Less vigorous attack occurred on trees deficient in magnesium, potassium or calcium; but nitrogen deficient trees, or those receiving complete nutrients, developed no macroscopically visible symptoms following inoculation. The fungus penetrated all inoculated limbs irrespective of treatment, but in complete and nitrogen deficient trees no attack on woody tissues developed. Phosphorus deficiency had only a slight effect on phosphorus content of leaves, but a very marked effect on bark and wood phosphorus. Analytical data presented in the paper demonstrates several interactions between elements.