ANTIFUNGAL ACTIVITY OF TWO PLANT EXTRACTS AGAINST Fusariun solani AND Rhizoctonia solani, THE CAUSAL PATHOGENS OF STEM AND ROOT ROT DISEASES OF POTHOS ( Epipremnum aureus ).

Abstract

Organic solvent extracts of lemon grass leaves were more effective than those of rhubarb roots in inhibiting mycelial growth of F. solani and R. solani , two fungi pathogenic to pothos plants causing root and basal stem rots. Superiority was realized as for ethanolic extracts than those extracted using hexane and ethyl acetate as organic solvents. Dipping root system of pothos cuttings in 20 % concentration of ethanolic extracts of lemon grass or rhubarb for 15 min. just before planting in soil infested with either of F. solani and R. solani recorded the lowest percentages of diseases incidence by (5 % & 10 %) and (15 % &20 %) , respectively , relative to those of their controls (40 % & 60 %). Values of physical characteristics of lemone grass essential oil such as specific gravity (0.89 %) , optical rotation (-1.6) , refractive index (1.4875) and acid number (8.3) were estimated. Also , chemical main compounds quantitatively determined by chromatography which confirmed that volatile matter of lemon grass oil represents 100 % of its composition. However , citral and myrecene constituted 77.0 % and 6.5 % of the total composition of that oil. Lemon grass essential oil at concens. of 10 % and 20 % could completely inhibit mycelial growth of the aforementioned two fungi , respectively .Besides , citral (2.5 concen.) realized the same effect , whereas, myrecene only minimized mycelial growth of these fungi by 40% and 28.6 % .

Effectiveness of some Plant Extracts as Safe Control Means against Damping-off and Root Rot Diseases in Canola Plants

“…Anju et al (2008) found that T. harzianum with 10 and 50% Neem leaf extract resulted in 100% inhibition of the growth of the pathogens Alternaria solani, Fusarium oxysporum and Colletotricum gloeosporioides [Glomerella cingulata] in vitro. EL Morsy et al (2011) found that organic solvent extracts of lemon grass leaves were more effective than those of rhubarb roots in inhibiting mycelial growth of F. solani and R. solani. Farag et al (2011) said that neem and willow aqueous extracts reduced the disease incidence of Fusarium wilt in tomato seedlings by increasing the activities of antioxidant defensive enzymes and decreasing the level of lipid peroxidation.…”