Control of Bacterial Leaf Spot of Zinnia with Captan. D. L. Strider, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Plant Dis. 64:920-922. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-920.

In dense plantings in the greenhouse, bacterial leaf spot of zinnia caused by Xanthomonas nigromaculans f. sp. zinniae (= X. campestris) was reduced from 100 to 2% diseased plants when infected seeds were treated with captan. Control was best using a 30-min seed-soak in 360 g a.i. captan per liter of water containing the wetting agent Tween 80. Dry treatment with captan 50 WP was not as effective, but the percent diseased plants was reduced from 100 to 12.4. In plant beds outside the greenhouse, spread was reduced by weekly foliar applications of captan (4.8 g a.i./L of water). Streptomycin was effective but moderately phytotoxic.