Bioactivity of Allium sativum L. and Datura stramonium L. Extracts on Rhizoctonia solani in tomato.

Abstract

Rhizoctonia solani is one of the most destructive pathogens causing damping off disease on tomato. This pathogen can survive in soil within diseased plant material as mycelia or sclerotia during unfavorable environmental conditions for several years. The pathogen is transported in infested soil or through movement of diseased plant tissues. Potential for seed borne inoculum also exists. Currently, no tomato varieties with resistance to damping-off are available. In addition, the agriculture industry is striving for sustainable and biological methods of control plant pests and pathogens. Therefore, affordable safe biological controls that are capable of effectively protecting plants from pathogens are needed. The synergistic effect of plant extracts is a combined integrated disease management approach for management of disease which has the efficiency to increase the plant growth. In this study, the antifungal activity of different concentrations (5%, 10% and 25%) of aqueous crude extracts of Allium sativum, Datura stramonium and a combination of Allium sativum and Datura stramonium mixture were assessed in vivo against Rhizoctonia solani in tomato. The objectives of the study were to determine the following: (i) bioactivity of A. sativum and D. stramonium crude extracts against R. solani in tomato. (ii) Comparison of the bioactivity of A.sativum with D. stramonium crude extract against R. solani in tomato. (iii) Comparison of the bioactivity of a combination of A. sativum and D. stramonium crude mixture with A. sativum and D. stramonium crude extracts against R. solani in tomato. Results from the analysis showed that the bioactivity of A. sativum was significantly higher than that of D. stramonium at all concentrations. Also, the bioactivity of D. stramonium and A. sativum crude mixture at [5%] on R. solani was significantly higher than that of individual crude extracts and significantly the same as the copper fungicide. A. sativum was not significantly different from the synthetic fungicide at 25%. It also showed that higher concentrations of the mixture (combination) reduced plantlet survival significantly. These results confirm the activity of the extracts against R. solani. The use of a mixture yields better results in ameliorating the soil-borne pathogen.