Effectiveness of Essential Oil Formula and Silica Against Diamond Shape Leaf Spot Disease in Red Ginger

Abstract

Abstract Diamond shape leaf spot disease caused by Pyricularia zingiberi is an essential disease in red ginger. This current research aims to identify the potency of essential oil formula and silica fertilizer against the diamond shape leaf spot disease. Efficacy of clove oil, lemongrass oil, and mancozeb as a control against the colony growth was tested by inoculating the fungus on PDA medium amended with 50, 100, 150, 200, 250, and 300 ppm of the tested fungicides. Compared to lemongrass oil, clove oil (LC50: 70,79 ppm) is more effective in suppressing the growth of P. zingiberi. In a greenhouse, the leaves of five months old red ginger plants were inoculated by spraying 105 conidia mL−1 suspensions of P. zingiberi. Foliar application of clove oil base pesticide and silica was carried out a month before pathogen inoculation, arranged in the factorial randomized complete design. The disease severity was measured monthly, and the data were analyzed using ANOVA. Disease severity on the plant treated by either clove oil base pesticide or silica was 9,08% and 8,71% lower than control (20,21%). Further research is still needed. Treatment with clove oil base pesticide or silica shows potency in reducing the disease severity.