IDENTIFICATION AND MORPHOLOGICAL CHARACTERIZATION OF PATHOGENS INFECTING MELIA DUBIA IN TAMIL NADU

Melia dubia in Tamil Nadu were surveyed for the association of foliar and root fungal pathogens were recovered from infected plants. Cultural and microscopic characterization of Fusarium moniliformis, Phoma sp., Rhizoctonia solani Lasiodiplodia theobromae and Pythium sp, were obtained. Fusarium moniliformis produced basal cells of macro conidia with prominent and the length ranged from 19.631 μm to 20.624 μm, foot shaped and elongated micro conidia length ranged from 6.648 μm to 7.250 μm. Phoma sp produced grey in colour mycelium, septate branched, pycnidia is colour black and it produced the spores in concentric circle. The length of the pycnidia was 68.906 μm and breadth was 103.61 μm. Rhizoctonia solani showed complete full growth in Petri dish, initially the mycelium aggregated and form ball like structure later it changed brown colour sclerotia. Pythium sp Showed hyaline, non-septate with granular cytoplasm and oospores like bodies much in number and sporangia pores length was 7.18 μm. Lasiodiplodia theobromae showed a fast growth and attained full growth within five days after inoculation in 9cm diameter Petri plate. Aggregation of grey coloured mycelium and production of pycnidia in the centre of the colony were observed eight days after inoculation. Among the media tested, the potato dextrose agar medium supported the growth of all fungal pathogens in terms of mycelial extension, mycelial density and sporangia production compared to oat meal agar and malt extract agar medium