Potential of Plant Extracts for Controlling Citrus Canker of Lime
Five plant extracts of Hibiscus subdariffa Linn., Psidium guajava Linn., Punica granatum Linn., Spondias pinnata (Linn.f.)Kurz, and Tamarindus indica Linn. were evaluated for control of canker disease on Citrus aurantifolia (lime) caused by Xanthomonas axonopodis pv. citri (XC) (synonym X. campestris pv. citri ) under greenhouse condition. Aqueous extracts of H. subdariffa, P. granatum, S. pinnata, and T. indica exhibited an inhibitory effect against XC lime strain Xci12 by reducing canker incidence vary from 18% to 52%. The extracts from T. indica was the most effective control of citrus canker which disease incidence was 48% by one spray after leaf puncture inoculation whereas the control was 100 %. In field experiment with natural infection of XC on lime, the aqueous extract of T. indica reduced number of diseased leaves. There was significantly difference in mean disease incidence between sprayed (3.59%) or not sprayed (9.46%) lime (P< 0.05).