Brown rot of potato is a worldwide disease that causes huge agricultural and economical losses. Using synthetic chemicals like antimicrobial pesticide may have adverse effects on consumers and on the environment. The recent trend of control plant disease is the application of eco-friendly tools to control disease. In the present investigation, and this study streptomycin, Pleurotus columbinus spent wheat straw (PCSWS), wheat straw (WS), three bacterial species (Bacillus subtillus, B. polymyxa and Pseudomonas fluorescens), plant essential oils of anethole, mustard, caraway and neem were tested to control brown rot disease of potato cv. Spunta in Baramoon Research Station, Dakahlia Governorate, Egypt under field conditions, during the two winter seasons of 2013/14 and 2014/15.
The vegetative growth parameters, tuber yield, tuber grading, tuber dry matter, specific gravity and infected tubers were investigated. PCSWS led to significant increase in all studied criteria, compared to check or other treatments. Furthermore, PCSWS or caraway oil gave the best results in reduction of infected tubers in vitro. The direct antibacterial effect of studied treatments against the causal pathogen of brown rot of potato; Ralstonia solanacerum. Only streptomycin, anethole and caraway oil affected the growth of R. solanacearum. Pots experiment was carried out to study the ability of the tested treatments to induce systemic resistance (ISR).
Conclusively, Bacillus subtillus, caraway and neem oils significantly increased the production of total phenols, polyphenol oxidase and peroxidase, respectively, which enhanced potato plant health, increased chlorophylls and plant height as well as, decreased disease rating that increased tuber weight after 70 days of planting.