SYMPTOM DEVELOPMENT AND TISSUE CONCENTRATIONS OF CHLORIDE AND BORON TOXICITY IN KIWIFRUIT
Chloride and boron toxicity symptoms and tissue concentrations were characterized and distinguished in kiwifruit. Dormant cane, bud, emerging leaves, blade and petiole samples were taken from February through October 1989 from three vineyards - a high chloride, a high boron and a low boron, low chloride control. Chloride toxicity symptoms started showing in early summer on basal leaves. By late summer, necrosis symptoms were on mid-shoot and leaves near the shoot terminal. In boron toxicity, interveinal chlorotic areas appeared first followed by marginal necrosis. Symptoms were seen on basal leaves in early spring, progressively affecting upper leaves by harvest. The high chloride vineyard accumulated chloride from early spring with the petiole concentrating more chloride than the blade. In the high boron vineyard, boron increased greatly in the blade but not in the petiole. Another sampling procedure other than mid-season leaf samples could be emerging leaves for detecting high chloride and dormant cane tips, buds or emerging leaves for high boron.