Phytophthora dieback - Phytophthora cactorum, P. nicotianae var. parasitica, P. citricola
Brown, irregular-shaped lesions on leaf margin that progresses along midrib through the petiole into the stem. Brown discoloration extending up and down the stem. Infection only on current season's growth, but slowly moves through plant.
Avoid prolonged plant wetness; do not water late in the day or evening. Prune affected shoots. Excess shade and nitrogen fertilization increases disease susceptibility. Susceptibility varies from cultivar to cultivar. Fungicides can reduce disease inicidence.
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Compiled by: Dr. Jean L. Williams-Woodward, UGA Extension Plant Pathology, Athens