Management of corm-rot disease of Gladiolus by plant extracts.

A pot experiment was conducted to evaluate the efficacy of aqueous extracts of six plant species, namely Azadirachta indica A. Juss. (neem), Alstonia scholaris (L.) R. Br., Lawsonia alba Lam., Allium cepa L., A. sativum L. and Zingiber officinale Roscoe, and a systemic fungicide carbendazim 50% (w/w) WP, to manage the corm-rot disease of Gladiolus (Gladiolus grandiflorus L.) caused by a fungal pathogen Fusarium oxysporum f.sp. gladioli (Massey) Snyd. & Hans. Fusarium inoculation showed 80% disease incidence with 54 disease lesions per corm. Recommended dose of the chemical fungicide carbendazim significantly reduced the disease incidence to 13% and number of lesions to six per corm. Plant extract treatments exhibited variable effects on the incidence and severity of the disease. In general, all the test plant extracts managed the corm-rot disease to some extent. Aqueous bulb extracts of A. sativum and A. cepa and the rhizome extract of Z. officinale showed better disease management potential than that of the recommended dose of carbendazim. Fusarium inoculation significantly declined shoot growth. In general, carbendazim, as well as aqueous extracts, enhanced shoot growth to variable extents as compared to the Fusarium control.