Management of citrus canker bacterium by using botanicals and chemicals

Abstract

Citrus is the important fruit crop in the world. It occupies an important place in the wealth and economy of India as third largest fruit industry after mango and banana. Citrus canker caused by Xanthomonas citri subsp. citri is a damaging disease of acid lime. It is identified as a major threat in the region affecting leaves, twigs, petioles, branches, fruit stalk and fruits that causes considerable damage both quantitatively and qualitatively. Canker infected sample of acid lime leaves were collected from different agroclimatic regions of Vidarbha. The bacterium were isolated, identified and purified cultures were maintained on NA slants. The virulence test of causal organism was confirmed along with symptoms in pot culture experiment using syringe method. Pathogenic ability of different isolates was confirmed and observed that isolate Xac-2 was comparatively highly virulent to initiate water soaked lesion and fully developed symptoms within 15 to19 days. Efficacy of different combination of chemicals, botanicals and bio-agents against Xanthomonas citri subsp. citri was assessed. Among the alcoholic and aqueous plant leaf extracts neem (Azardiricta indica) at all concentrations found most effective in alcoholic extracts by developing 13.45 mm, 11.70 mm, 10.12 mm and 8.2 mm of inhibition zone at 20% 15%, 10% and 5% respectively. Among fruits extracts, alcoholic extract of Kokam (Garcinia indica) gives highest inhibition zones 17 mm, 15.0 mm, 6.9 mm and 0 mm at 20% 15%, 10% and 5% concentrations and found to be most effective. Among flower extracts, alcoholic extract of lakh (Lathyrus odoratus) showed highest inhibition zones 13.14 mm, 9.23 mm, 8.00 mm and 6.23 mm at 20% 15%, 10% and 5% concentrations. Among the extracts of different vegetative parts of plants alcoholic extract of garlic (Allium sativum) produced highest inhibition zones 16.20 mm, 13.40 mm, 7.23 mm and 0.00 mm at 20% 15%, 10% and 5% concentrations.