IN VITRO EVALUATION OF SOME PLANT EXTRACTS AGAINST Alternaria alternata CAUSING LEAF SPOT OF Aloe vera

Aloe Vera (L.) Burn f. is a perennial succulent plant grown worldwide mainly for medicinal and cosmetic uses. During a routine survey a leaf spot disease of Aloe vera having infected plants with large necrotic, sunken, circular to oval, dark brown spots present on both surface of leaves was observed at SHIATS and neighboring areas. Microscopical examination revealed the presence of Alternaria alternata in the infected areas. Pathogen was isolated and cultured on Potato Dextrose Agar medium. Leaf extracts of six plants viz, Jatropa curcas, Datura strumarium, Azadirachata indica, Moringa oleifera, Calotropis gigantean and Morus Alba @ 50% were evaluated In vitro by food poison techniques against the fungus. The results revealed that all plant extracts @ 50% significantly inhibited the mycelial growth of pathogen. However leaf extract of J. curcas demonstrated maximum mycelial growth inhibition of A. alternata (62.9%) followed by D. strumarium leaf extract (55.6%) and was significantly superior to all other tested extracts. A. indica extract (51.9%) also inhibited its mycelial growth followed by M. oleifera (46.9%), C. gigantea extract (23.45%) and M. Alba (13.6%) as compared to control.