Effect of Some Essential Oils against Rhizoctonia solani and Streptomycetes scabies on Potato Plants in Field Conditions

Abstract

Aim: In this study, efficacy of six essential oils (Cuminum cyminumum, Anethum graveolens, Salvia officinalis, Origanum onites, Rosmarinus officinalis and Lavandula intermedia) in control of Rhizoctonia solani and Streptomycetes scabies on potato plants were tested. Material and Methods: Essential oil solutions of each species were sprayed uniformly (10 ml for each plant) to aerial parts of potato plants with a manually operated sprayer, when potato plants reached at 15-20 cm height. Controls were sprayed with DMSO (0.5%) and Tween 20 (0.1 %) solutions. Essential oil treatments were repeated 15-day intervals for three times. Plants were harvested in September. Infection of harvested tubers by Rhizoctonia solani and Streptomyces scabies was rated in each plots. Results: Origanum onites and Anethum graveolens oils reduced disease severity of S. scabies, whereas Lavandula intermedia poorly affected S. scabies. Disease severity of R. solani was 4-4.2% for the Salvia officinalis oil. Disease development was also controlled in the field with the Salvia officinalis oil reducing infection of potato tubers significantly. However, the effectiveness of these essential oils with both the tested pathogens showed different responses. Conclusion: This study suggests that essential oils have potential as antimicrobial preservatives for the control of Rhizoctonia solani and Streptomycetes scabies on potato plants in filed conditions.