New Diseases and Epidemics Root Rot of Bamboo Palm Caused by Phytophthora arecae. R. C. Ploetz, University of Florida, IFAS, Tropical Research and Education Center, 18905 S.W. 280th Street, Homestead 33031. D. J. Mitchell, Department of Plant Pathology, 1453 Fifield Hall, University of Florida, IFAS, Gainesville 32611. Plant Dis. 73:266-269. Accepted for publication 20 October 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0266.

Phytophthora arecae caused a blackened, water-soaked necrosis on roots and shoots (formed beneath the soil) of bamboo palm (Chamaedorea seifrizii × erumpens). Under controlled conditions, the fungus primarily infected apical portions of roots of this ornamental palm. Root rot severity and recovery of the pathogen from necrotic root tissue were reduced by both fosetyl-Al and metalaxyl fungicides. Dry matter accumulations and root:shoot ratios were not influenced by treatment with either of these fungicides, however. Watering schedules of every 1, 2, 4, or 6 days had no effect on dry matter accumulations, root:shoot ratios, root rot severities, or recovery of the pathogen. Although P. arecae may be a soilborne pathogen of only minor concern on bamboo palm, its soilborne role with palms on which it can induce a foliar disease phase may be important epidemiologically.

Keyword(s): bud rot and nut fall of coconut palm.