LAUSR

Symbiotic pathogenic microorganisms associated with P. colocasiae leading to the manifestation of taro mildew have been identified and studied. The experiment was carried out in an experimental set-up consisting of completely randomized blocks with three treatments (infection with the pure strain, with the unpurified strain and a co-infection with both strains). Isolation and purification of the microorganisms was carried out in the PDA medium and the identification on the analysis of the macroscopic and microscopic morphological characters. The results of the trapping revealed among several a single microorganism which has a high affinity with P. colocasiae, this microorganism named Vorticella is identified as the agent of the amplification of the severity of the downy mildew. Greenhouse studies of taro plants showed that the unpurified strain caused enough damage with 96.67% disease incidence and a severity of 70.18% compared to plants inoculated with pure strain which had an incidence of 40% and a severity of 10.48%. All these results show that P. colocasiae is the causal agent of the mildew of the taro in the infection and the development of the disease; it is accompanied by other microorganisms with which it forms a biofilm. In this biofilm there is a microorganism which plays a very important role in the spread of the disease and it is thanks to it that all parts of the plant are attacked.