BACTERIAL BLACK SPOT OF MANGO – A NEW DISEASE IN MALAYSIA

The total hectarage of mango in Peninsular Malaysia is about 7200 ha, and most of this is found in the states of Perak, Perlis, and Kedah.
In February-March, and September-November, 1988, many orchards ;in these states were afflicted by a new bacterial disease which inflicted the fruits and foliage.
More than 50% of crop losses were reported in some orchards.
The bacterium was isolated on sucrose peptone agar and SX media, and identified as Xanthomonas campestris pv. manqiferaeindicae through a series of 15 confirmatory physiological tests, and a pathogenicity test on the fruits and leaves of MA 162, a highly susceptible cultivar.
Based on the assessment of a disease severity index, the cultivars were categorised into various susceptibility classes:

1. highly susceptible – MA 162, MA 165, MA 152 (Kent), MA 151 (Keitt), MA 150 (Irwin), and MA 146 (Haden);

2. moderately susceptible – MA 128 (Harumanis), MA 173 (Alphonso), and MA 203 (Bombay Green);

3. tolerant – MA 125 (Siam Panjang), MA 217 (Karutha Kolumban), MA 200 (Apple mango), and Intan Safinas.

Based on a preliminary fungicide trial in September-November, 1988, a wettable formulation of copper oxychloride was found to be more efficacious than similar and micronised formulations of other copper fungicides.

III International Mango Symposium

T.K. Lim, K. Sijam, E.T. Ong

https://doi.org/10.17660/ActaHortic.1991.291.36