Azadirachta indica leaf extract induces resistance in sesame against Alternaria leaf spot disease

Induced resistance is an important component of disease-resistance response of plants, and is accompanied by increased capability for activating defense responses upon pathogen ingress or elicitor treatment. Aqueous leaf extract of neem (Azadirachta indica Juss.) provided the control of Alternaria leaf spot pathogen (Alternaria sesami) of sesame (Sesamum indicum L: Syn. S. orientale L). Treatment with this extract led to the changes in plant metabolism as leaves of the treated plants exhibited significantly high level of enzymes phenylalanine ammonialyase (PAL), peroxidase (PO) and content of phenolic compounds. Further more, germination of A. s e s a m i spores was not significantly inhibited by neem extract. It is therefore, suggested that, protection of sesame plants against A. s e s a m i by neem extract might be due to stimulation of plants natural defence response.