COPPER TOXICITY IN WOODY ORNAMENTALS

boxwood) and Cotoneaster divaricata Rehd. and Wils. (spreading cotoneaster) grown in sand culture received a complete nutrient solution containing Cu concns ranging from 0.032 ppm to 100 ppm. Development of Cu toxicity symptoms were recorded for 8 weeks, then Cu, Fe, and Mn levels in roots, stems, and leaves were determined. Chronic Cu toxicity symptoms were interveinal chlorosis and stunted growth. Acute Cu toxicity caused wilting, desiccation, and death of all affected plants. Tissue Fe and Mn levels were not consistently correlated to the Cu concn of the treatment solu-tion. Only tissue Cu levels proved useful as an index of Cu toxicity. Copper toxicity symptoms have been recorded for a number of fruit and agronomic crops (3), but not for ornamentals. Ornamentals may also b