Essential oils, inorganic acids and potassium salts as control measures against the growth of tomato root rot pathogens in vitro.

Abstract

Evaluation the inhibitor activity of some fungicides alternatives on the growth of some tomato root rot soil-borne pathogenic fungi (Fusarium oxysporum radicis-lycopersici, F. oxysporum lycopersici, F. solani, Rhizoctonia solani, Sclerotium rolfsii, Macrophomina phaseolinae, Pythium sp. and Phytophthora sp.) was studied under in vitro conditions. The evaluated chemicals were inorganic acids and salts, i.e. Salicylic, Sorbic acids, Potassium sorbate, Potassium carbonate, as well as essential oils were lemongrass, Thyme, citral and nerol. Linear growth of tested fungi decreased significantly by increasing the concentrations of both salicylic and sorbic acids. The fungal growth was completely inhibited at concentration of 12.5 mM of both salicylic and sorbic acids. Meanwhile, potassium sorbate and potassium carbonate had inhibitory effect against mycelia growth of all tested fungi in vitro. The inhibitory effect increased by the increase in concentration used to reach its maximum at the highest concentration of 4%. Furthermore, the inhibitor activity against mycelial growth of tested fungi was also observed at all concentrations of lemongrass, thyme, citral and nerol oils. The Mycelial growth decreased significantly with the increase in concentrations of essential oils and reached minimum mycelia growth at the highest concentration used. A complete inhibition of fungal growth was observed at 1.5% of all tested essential oils. The obtained results in the present study provide that fungicides alternatives could be effectiveness in management tomato soilborn pathogenic fungi.