Phosphite-based Products in the In vitro Colletotrichum musae Control

Aims: The aim of this study was to evaluate the in vitro effect of different phosphite formulations and concentrations on the development of Colletotrichum musae. Sample: to evaluate the inhibition of germination, mycelial growth and sporulation of Colletotrichum musae.

Study Design: Treatments were conducted in a completely randomized design, with 4 replicates, each replicate consisting of 1 Petri dish.

Place and Duration of Study: Laboratory of Post-Harvest Pathology, State University of Montes Claros, between March and October 2017.

Methodology: Three different phosphite formulations were used: FCu1 (4% Cu + 20% P2O5), FCu2 (4% Cu + 22% P2O5) at concentrations of 0.5;1.0; 1.5 and 2.0 mL L-1 and FK (42% P2O5 + 27.7% K2O) at concentrations of 0.5; 1.0; 1.5 and 2.0 mg.L-1. Products were incorporated into the respective culture media. Culture medium alone and culture medium + imazalil were used as controls. Petri dishes were housed in BOD chamber at 25°C under a 12 hours photoperiod.

Results: Results were submitted to analysis of variance and regression, and means were compared by the Tukey test (P <0.05). Control was compared to the other treatments by the Dunnet's test (P <0.05). Among the tested phosphite formulations, copper and potassium phosphites were found to reduce the mycelial growth of Colletotrichum musae. FCu2 presents a fungicide-like effect from the concentration of 0.5 m.L-1 in the control of conidia production. As for the FCu1, a fungicide-like effect was observed in the control of germination from the concentration of 1.5 mL.L-1.

Conclusion: A significant fungistatic effect was observed between the concentrations of the products in the mycelial growth, sporulation and germination obtaining control of up to 100% of the development of C. musae. Copper phosphites were as effective as fungicide in inhibiting fungal development.