Azadirachta indica leaf extract induces resistance in barley against leaf stripe disease

Aqueous extract of leaves of neem (Azadirachta indica Juss.), provided control of leaf stripe pathogen (Drechslera graminea) on barley that was as effective as the fungicide bavistin (carbendazim). The treated leaves exhibited significantly high activity of enzymes phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) alongwith rapid and distinct accumulation of fungitoxic phenolic compounds. The population of most phylloplane mycoflora species remained unaltered except for a few species which were inhibited by the leaf extract. Germination of spores of D. graminea was not significantly inhibited by neem extract. The results support the hypothesis that neem extract may act indirectly by inducing plant defence reactions and it may be useful in integrated management of leaf stripe disease of barley. [Copyright &y& Elsevier]