Pineapple mealybug wilt (PMW) was first described in Hawaii in 1910 and has since spread wherever pineapple is cultivated. PMW is currently one of the most important field diseases of pineapple in Cuba, causing up to 40% crop loss. Leaves of plants affected with PMW turn bronze-red and lose turgidity, and the tips curve down. Root system size is decreased and fruits are unmarketable because the flesh is fibrous and sour. Leaves from wilt-affected pineapple plants were selected from the Experimental Station “Tomás Roig” at Ciego de Avila, Cuba. Asymptomatic plants derived from meristem tissue and cultivated under greenhouse conditions were also collected. Both samples were analyzed by several virus purification procedures and finally purified with a protocol modified from Gunashinge and German (1). Partially purified samples from symptomatic and asymptomatic plants were negatively stained and examined by a JEOL (JEM-2000 EX) transmission electron microscope at a magnification of ×30,000. Sixteen, long, flexuous, rod-shaped, viruslike particles (estimated length 1,200 to 1,450 nm; width about 12 nm) were observed in symptomatic leaves, using electron microscope micrographs. These particles were similar to those of the pineapple clostero-like virus found in Hawaii (1) and Australia (2). Particles were observed from symptomatic plants but not from plants propagated by primary meristem culture. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of viral proteins indicated that the coat protein has a molecular mass of approximately 23 kDa. This is the first report of closterovirus-like particles associated with pineapple plants (Ananas comosus cv. Smooth Cayenne) affected with PMW in Cuba. References: (1) U. B. Gunasinge and T. L. German. Phytopathology 79:1337, 1989. (2) W. Wakman et al. Aust. J. Agric. Res. 46:947, 1995.
First report of Pineapple mealybug wilt associated virus-2 infecting pineapple in Ghana