A comparative study into the pathogenicity of four Helminthosporium spp. towards rice cultivars in Marocco

In this paper, the behaviour of four Helminthosporium species on nine rice cultivars widely cultivated in Morocco, permit the classification of this s pecies according to their virulence. Helminthosporium oryzae and Helminthos porium sativum are the most virulent and the best equipped to sporule on al l varieties of tested lesions. The level of pathogenicity of Helminthospori um spiciferum and Helminthosporium australiensis and their capacity to spor ule on host plant depend on the rice variety used. At the same time, each H elminthosporium induces characteristics symptoms on rice leaves.