Airspora measured in a paddy field in West Bengal, India

Abstract

Aeromycoflora studies above an “Aman” variety of paddy (Oryza sativa L.) were carried out for two consecutive seasons, in 1990 and 1991, in the vicinity of Barrackpore, West Bengal, by means of the culture plate exposure technique. A more or less uniform spore concentration was observed during the early part of the vegetative stages in 1990 with an abrupt increase and peak during the maximum vegetative growth period. In 1991, a uniform spore count was found up until the flowering stages. A gradual increase in spore count after flowering was recorded in both seasons with the highest peaks during harvesting, followed by a sudden decrease after the harvest. The dominant genera isolated were Aspergillus, Curvularia, Cladosporium and Penicillium. Aspergillus appeared in high concentrations from the very beginning of the crop season up to the flowering stages, with a gradual fall after flowering, while Cladosporium showed the reverse pattern. Curvularia and Penicilliun occurred regularly through­out the crop season. Phytopathogenic types were represented by Helminthosporium oryzae, Fusarium, Alternaria and Nigrospora. Helmmthosporium oryzae appeared in the air when the plants attained appreciable vegetative growth, being seen as “brown spots” on the foliage, and reaching peak concentration during harvesting. Fusarium in contrast to Alternaria appeared regularly in the air except during the later part of vegetative growth. Nigrospora was recorded only occasionally. A considerable number of “Sterile Forms” were present throughout both seasons. © 1995 Scandinavian University Press.