Effect of Various Compounds on the Control of Alternaria solani and Alternaria alternata the Causal Agents of Early Blight Disease on Potato

Early blight is one of the most common and important disease that causes damage to most Solanaceos plants. At the present time, the most practicable way of control of the disease is using fungicides. Due to the importance of alternarios and excessive use of chemical compounds, this study was conducted to evaluate the effectiveness of non-toxic compounds in controlling the disease and comparing them with common fungicides. In this study, the effect of NaHCo3, CaCl2 salts, biological compound of Bacillex, clove oil, Rovral Ts and Dakonil fungicides on growth of fungal species Alternaria solani and A. alternata in vitro and the disease severity of resulting them in greenhouse have been investigated. The results showed that all the compounds inhibited the mycelium growth of two species of fungi in vitro except Daconil. The maximum growth inhibition was done with Rovral Ts and sodium bicarbonate at concentration of 30 ppm and 35 mg/ ml respectively. Greenhouse experiments indicated that tested compounds were effective in the disease severity reduction. Maximum reduction of disease severity in greenhouse due to Rovral Ts, Daconill, sodium bicarbonate, calcium chloride, Bacillex and clove oil were 33/88, 93, 33/92, 93, 33/70 and 74%, respectively.