Effect of sodium bicarbonate on Alternaria solani in tomato

Considering the public concern about the use of pesticides in plant protection and the frequent appearance of pathogen resistance to pesticides, the effects of sodium bicarbonate (NaHCO3) as an alternative 'biocompatible' fungicide in the control of plant diseases, were investigated. The inhibitory effects of sodium bicarbonate (SBC) on conidial germination and mycelial growth of Alternaria solani (Sorauer), causal agent of tomato target spot were studied in vitro using four different concentrations of SBC (0.5, 1.0, 2.0, 5.0%). The same concentrations of SBC were used for spraying tomato plants before or after artificial inoculation with the pathogen. The SBC treatment inhibited the conidial germination by 72-95%. In the case of treatment with SBC before inoculation, germination was slightly inhibited. The inhibitory effect of SBC on hyphal growth was not statistically significant. The SBC provided good control of target leaf spot of tomato in greenhouse trials only when used at the highest concentration (5%). The bicarbonate treatments were more effective when applied prior to inoculation