關鍵字： 病害；番石榴；褐枝 ；Disease；Psidium Guajava；Brown Discoloration of Twigs
摘要： 番石榴發生一新型態的病徵，農民一般稱之為「裂枝」、「黑心」、「芽枯」或「乾枝」，因其造成枝條有流汁之水浸狀、皮層縱向開裂，及枝條中軸褐化的主要病徵，且受害結果枝下位葉易黃化脫落，或於短期內乾枯褐化，但不立即脫落。由於此病徵未曾被描述，故本研究將證明其病因、感染點、感染源及化學防治方法。The project will focus on an undescribed symptom of guava disease in Taiwan. The common names of the symptom called by farmers are cleaved twigs, black pith, shoots blight, and twigs blight. The infected twigs appear water soaking or longitudinal clefts on epidermis, and internal brown discoloration will be observed after they are cut away. Leaves of infected twigs, moreover, may blight in few days, or gradually yellow from the lowest one and readily fall. The research will conform the causal organism, infection points, positions of survival inocula, and chemical agents of control.