The Effectiveness of Rhizosphere Bacteria in Inducing the Resistance of Maize to Downy Mildew Peronosclerospora philipinensis NURASIAH DJAENUDDIN, MUHAMMAD AZRAI, TUTIK KUSWINANTI, BAHARUDDIN PATANDJENGI
1. Program of Magister, Department of Plant Pests and Diseases, Faculty of Agriculture, University of Hasanuddin
2. Indonesian Cereals Research Institute
Abstract
Downy mildew caused by Peronosclerospora philipinensis is a major disease of maize. The disease is currently managed by seed treatment with metalaxyl fungicides, but the development of pathogenic fungi resistance towards synthetic fungicides is a great problem affecting significantly the future of chemical control by fungicides. The use of microorganisms for induction of systemic resistance against pathogens on maize is well known. Therefore, this study aims to determine the efficacy of bacterial isolates from the rhizosphere in influencing the resistance of maize to downy mildew by measuring accumulated concentration of salicylic acid. Treatments were based on a fully randomized 2-factor design with 3 levels of- factor I (bacteria) 3 levels (b0 = no bacteria, b1 = Bacillus paramycoides Ga-3, b2 = B. cereus Si-4) and factor II (salicylic acid) 2 levels (as0 = 0 g/L and as1 = 2 g/L). The research was carried out at the screenhouse and plant pathology laboratory, Indonesian Cereal Research Institute (ICERI), from March to July 2020. Each treatment combination was tested on three varieties of maize, namely Anoman, Bima20, and Bima3, hence there were 18 treatment combinations. Furthermore, the results showed that the use of rhizosphere bacteria and salicylic acid has the potential to control downy mildew in maize. In the case of the Bima20 variety, the combined treatment of B. paramycoides Ga3 + salicylic acid had the lowest incidence of disease. Meanwhile, treatment of B. cereus Si4 + salicylic acid in Bima3 variety had the lowest incidence of disease, namely 13.9% and 26.1%, respectively. Considering the results, the enrichment of salicylic acid content was highest at 9.6 ppm on maize which were applied with the rhizosphere bacterium B. paramycoides Ga3 + salicylic acid.
