Study on efficacy of some botanicals against Colletotrichum gloeosporioides causing anthracnose disease in brinjal

Abstract

Anthracnose disease is one of the major problems in brinjal (Solarium melongina L.) cultivations and the use of ecofriendly botanicals for the control of this disease is a better alternative to synthetic fungicides. Laboratory studies were carried out to test the effect of some selected botanicals against Colletotrichum gloeosporioides causing anthracnose in brinjal and to select the most effective concentrations. Water extracts of Garlic (Allium sativum) bulbs, Tumeric rhizomes (Curcuma domes tied), Heen Aratta rhizomes (A Ipema galangd), Guava leaves (Psidium guajavd) and Wathupalu leaves (Michania spp.), were prepared as 0.05%, 0.1 %, 0.5%, 1.0% and 1.5% dilutions while sterilized distilled water was used as the control. Separate experiments for each botanical was arranged in a Completely Randomized Design (CRD) with the above five treatments with three replicates. Solutions from each concentration were incorporated to Potato Dextrose Agar (PDA) medium by the pour plate method. Those plates were centrally inoculated with 1 cm diameter mycelial discs of C. gloeosporioides, sealed and incubated at room temperature (28 °c + 1 °c). Colony diameters of the growing fungus were measured every other day (starting five days after inoculation). Significantly lower (P ^ 0.05) colony diameter was seen in 0.5% concentration of garlic compared to other concentrations. The inhibition of fungal mycelium was highest in turmeric at 0.5%, and Heen Aratta both at 0.5% and 1.0% concentrations. All the concentrations tested with Wathupalu and Guava leaf extracts showed significantly lower mycelial growth than the control. When all those best concentrates were tested together, 0.1%, 0.5% and 1.5% concentrations of Guava leaf extract and 1.5% concentration of Wathupalu leaf extract showed significantly lower colony diameters than the other effective concentrations of Garlic bulbs, Tumeric rhizomes and Heen Aratta rhizomes