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Bacterial Wilt of Diploid Musa Caused by Pseudomonas solanacearum Race 1 in Australia. E. Akiew, Plant Pathology Branch, Queensland Department of Primary Industries, Mareeba, Queensland 4880, Australia. . Plant Dis. 76:753. Accepted for publication 20 February 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0753C.

In March 1991, race 1 of Pseudomonas solanacearum (Smith) Smith was isolated from diseased Musa shizocarpa Simm., a diploid banana species introduced to Australia from Papua New Guinea for breeding purposes. The plants were derived from tissue culture and grown among several banana breeding lines in a field nursery at South Johnston Research Station, North Queensland. Diseased plants had irregular, soft patches of black rot on the pseudostem, dark brown to black necrotic lesions in the vascular tissues, and droplets of brown, slimy bacterial ooze on cut surfaces of the pseudostem. The bacterium had high tyrosinase activity on tyrosine-supplemented medium and oxidized mannitol, sorbitol, dulcitol, cellobiose, maltose, lactose, and trehalose. Colonies were irregularly round, fluidal, and creamy white with pink-orange centers on Kelman's tetrazolium medium. These strains were not pathogenic on triploid banana (cv. Williams) but were virulent on seedlings of diploid bananas M. shizocarpa, M. acuminata subsp. banksii Simm., and M. lolodensis Chee. and on seedlings of Lycopersicon esculentum Mill., Solanum melongena L., and Arachis hypogaea L. 'Red Spanish'. The strains were considered race 1. The banana cultivars were also susceptible to a number of P. solanacearum race 1 strains from nonmusaceous hosts. On inoculated seedlings of Sucrier (AA), a cultivated form of M. acuminata, the banana isolates did not induce bacterial wilt symptoms except yellowing of leaves and stunted growth, whereas isolates from Heliconia from nurseries in adjacent localities caused severe wilt. Certain race 1 strains of P. solanacearum in Australia appear to be pathogenic on some musaceous hosts, and I believe these strains would be found in some wild diploid banana species in the region. This is the first report of bacterial wilt of diploid banana in Australia and outside Latin America (1).

Reference: (I) I. W. Buddenhagen. Aust. Cent. Int. Agric. Res. Proc. 21:95, 1986.