Effect of climate on development of mango bacterial black spot and chemical control.
Ann P. J.
Author Affiliation: Chia-yi Agricultural Experiment Station, Chia-yi, Taiwan.
Plant Pathology Bulletin 2 : 12-19
Abstract : During 1977-79 young green leaves of the cultivars Irwin and Keitt were inoculated with Xanthomonas campestris pv. mangiferaeindicae every week by puncturing with needles that had been dipped in a suspension containing 108-109 bacterial cells/ml. The incubation period was 5 d in Apr.-Sep. and ?10 d in Oct.-Feb. Rainfall, high RH (>90%) and high temp. (>25°C) favoured disease development. New spots appeared on mango leaves more frequently in summer than in the winter but they were observed in the orchards throughout the year, indicating that the bacterium survived on the mango tree. Spots were most frequent on young and mature green fruits. Among 12 chemicals tested, copper oxychloride, tetracycline, cuprous oxide, Bordeaux mixture and streptomycin inhibited growth of the pathogen on PDA. Only 8-8 and 10-10 Bordeaux mixtures, applied before inoculation, were effective in reducing disease incidence to 30-40%.