Comprehensive investigation into pathogenicity, cultural characteristics, germplasm resistance and management strategies Macrophomina phaseolina causing castor root rot
CP Manjula, Sangeeta AG, Yamanura, Divyashree, G Punith, Sushmita, Harish J and Lakshmeesha R
Castor (Ricinus communis L.) is an important non-edible oil seed crop in the world. The crop is prone to many diseases, among them root-rot poses serious threat to the crop resulting in reduced crop stand and yield. It affects all parts of the plant viz., root, stem and collar region. The fungus isolated from infected region were characterized through morphological and which was identified and confirmed as Macrophomina phaseolina(Tassi) Goid. The fungus showed highest growth in Sabouraud’s dextrose agar (88.77 mm) followed by Potato dextrose agar (84.32 mm). The pathogen exhibited good growth with increase in temperature up to 40 ºC (87.00 mm) and an optimum pH range of 6.0 to 7.0. Under in vitroassessment, fungicides viz., Mancozeb and Propineb (500, 750 and 1000 ppm), Tebuconazole (50, 100 and 150 ppm) and Carbendazim + Mancozeb (100, 250, 500 and 1000 ppm) recorded 100 per cent inhibition of the pathogen. Among the fungal antagonists, Trichoderma harzianum GJ 16B (52.84%) and T. viride 8 (52.23%) and bacterial antagonists Bacillus pumilis (33.10%) exhibited maximum inhibition in vitro. Out of 54 germplasm screened, BCG-2 showed absolute resistance while MI-54 exhibited high resistance to root-rot.
