Diplodia Stem Canker and Die-back of Casuarina equisetifolia in Puerto Rico

Diplodia natalensis was isolated from the diseased cankers of Casuarina equisetifolia in Puerto Rico. A stem-puncture technique was employed to inoculate Casuarina seedlings. Sunken areas or cankers appeared on the bark 3 months after inoculation. The causal organism was reisolated. Among the fungicidal chemicals tested (Dithane M-45, Thiodan, Captan, Benlate and benzoic acid), Benlate seemed to be the most promising for inhibiting mycelial growth of D. natalensis in vitro.