Seedling blight of sugarcane - A new disease caused by Drechslera state of Cochliobolus spicifer.

Sugarcane nurseries raised from fluff were found to be infected with a deuteromycetous fungus namely Drechslera resulting in seedling blight. The causal organism was later identified as Drechslera state of Cochliobolus spicifer, The disease incidence varied from 10-30% and the seedling mortality ranged from 50-95%. Studies were conducted on isolation, symptomatology, etiology. varietal reaction, morphology and identification of the pathogen including some control aspects under laboratory conditions. Etiological studies revealed that there was 8-16% infection of the fluff obtained from different crosses and open pollination. Artificially infected seedlings exhibited the same symptoms that were observed on diseased seedlings under natural conditions. The seedling mortality under artificial inoculation varied from 85-100%. All the four sugarcane varieties tested for their reaction to artificial inoculation were observed to be susceptible but the degree of susceptibility varied. Among 10 chemicals tried for control dithane-M 45, thiride, brassicol, zineb and ziram proved the best in inhibiting more than 50% of the conidial germination and also the growth of the mycelium. Kasumin proved very poor in its fungitoxic property. [ABSTRACT FROM AUTHOR]