IN VITRO EVALUATION OF ESSENTIAL OILS AGAINST RHIZOCTONIA SOLANI (KUHN) THE CAUSAL OF SEEDLING DAMPING OFF DISEASE.

Fourteen fungal isolates were isolated from infected tomato roots from Jazanrejion, Southern of Saudi Arabia (KSA) on potato dextrose agar (PDA) medium and corn meal agar (CMA). Among the isolates the most serious soil and seed-borne fungus R. solani,wildspread fungus of seedling damping-off disease for many field, horticulture crops alover the world.Five essential oils of different medicinal plants were evaluated for their effect on the suppression of R. solani.The oils were Eucalyptus (Eucalyptus globulus), Lemon Tea Tree (Melaleucaalternifolia), Peppermint ( Menthapiperita ),Lemon (Citrus limonum ) and Angelica (Angelica archangelica) .A reduction in the mycelium linear growth by increasing the oils concentrations was observed. The tested oils inhibited the mycelium growth of R.solani at different concentrations. Oils at higher concentrations gave an inhibitive effect while lower concentrations had a static action on the mycelialgrowth. Obtained results clarified that,peppermint (Menthapiperita ),and Lemon ( Citrus limonum ) oils at 2% caused 100% suppression of the fungal growth for all tested essential oils .Also, a clearfungistatic effect was recorded at the higher concentrations.