台灣發生由Acidovorax avenae subsp. avenae引起之薑黃葉枯病

Irregular browning lesions were seen at the leaf margins of turmeric plants cultivated in Minjeng and Tstun of NanTou county in the summer of 2006 in Taiwan. Water-soaked lesions first appeared at leaf hydathodes; as the disease progressed, necrotic lesions surrounded by a yellowish halo spread along the veins and eventually led to blighted plants. The same symptoms were also found on leaf sheath and finally the plant wilted. A gram-negative, rod-shaped bacterium was constantly isolated from the diseased tissues and identified as Acidovorax avenae subsp, avenae based on its physiological and biochemical characteristics, the Biolog GN MicroPlate Identification System, fatty acid analysis, and pathogenicity tests. The isolated bacteria were further confirmed by nested-PCR with Aaaf3/Aaar2 and Aaaf5/Aaar2 primers. According to the symptoms on the turmeric plants, the disease was designed as a baitenal leaf blight of turmeric. In vitro screening for the efficacy of various agrochemicals to inhibit the growth of A. avenae subsp. avenae on nutrient agar (NA) showed that all tested chemicals, including copper bacteriocides, antibiotics, oxolinic acid, and carbamates, were effective, and antibiotic tetracycline was the most effective.