Effect of some botanicals in management of Alternaria blight of rapeseed-mustard

Among all the extracts tested, Eucalyptus leaf extract showed significant reduction in radial growth, sporulation and spore germination. Under Laboratory conditions, leaf extracts of Eucalyptus, Ocimum and Anagallis showed maximum reduction (92.5%, 91.6%, 91.4% decrease over check respectively) in radial growth whereas Ocimum, Eucalyptus and Urtica showed minimum sporulation intensity (0.26, 0.28, 0.81X10⁵ respectively). Significantly lowest reduction of spore germination was observed with Urtica followed with Ocimum and Eucalyptus (86.6%, 79.4% and 78.9%, respectively). Studies carried out under glasshouse conditions revealed that Eucalyptus spray gave significantly lesser number of sports/leaf (2.05), minimum size of sport (1.28 mm), minimum sporulation intensity (1.22X10⁵) and minimum disease index (13.96) followed by Calotropis, Ocimum and Polyanthai extracts spray.