In vitro antifungal/fungistatic activity of manganese phosphite against soybean soil-borne pathogens

Soybean root and stem rots caused by soil-bornepathogens are diseases commonly found in soybean fields, and oneof the most important causes of crop losses. In the present study, themycelial sensitivity of Fusarium virguliforme, F. tucumaniae, Sclerotiniasclerotiorum and Macrophomina phaseolina was evaluated on potatodextrose agar media (25 mL) supplemented with different concentrationsof manganese phosphite (MnPhi) diluted in water (0, 25,37.5, 50, 100, 200, 300, 400, 500, 800 and 1000 μg/mL). Mycelialgrowth sensitivity was analyzed using logarithmic linear regressionanalysis. The MnPhi concentration needed to inhibit 50% of the mycelialgrowth (IC50) ranged from 105 μg/mL (Fusarium spp.) to 409μg/mL (M. phaseolina). Sclerotia were completely inhibited at 500μg/mL. The results of our study represent the first report on the directin vitro fungicidal/fungistatic action of MnPhi against fungi thatare causal agents of soil-borne diseases.