In vitro SENSITIVITY OF Pseudocercospora fijiensis (MORELET) TO SYSTEMIC FUNGICIDES

Abstract

Banana (Musa spp.) is affected by various diseases that reduce yield and quality. Black Sigatoka (Pseudocercospora fijiensis) is the main phytopathological problem in this crop; thus, the sensitivity of P. fijiensis to five systemic fungicides (Tebuconazole, Bitertanol, Pyrimethanil, Trifloxystrobin and Tridemorph) was studied in three Banana Production Units (BPU). Germ tube length, efficacy and EC₅₀ were evaluated. In BPU 1, 2 and 3, Tebuconazole inhibited the germ tube of P. fijiensis with 86 % efficacy, Bitertanol with 87 %, Pyrimethanil with 100 %, Trifloxystrobin with 97 % and Tridemorph with 95 %. Tebuconazole had an EC₅₀ of 0.05694 ppm, Bitertanol of 0.0001 ppm, Trifloxystrobin of 0.00332 ppm, Pyrimethanil of 0.15099 ppm and Tridemorph of 0.00166 ppm. The fungicides Tebuconazole and Bitertanol had the best results in BPU 1, Pyrimethanil in BPU 1 and 2, Trifloxystrobin and Tridemorph in BPU 3, due to the fact that they inhibited the growth of the germ tube P. fijiensis to a greater extent. The fungicide Pyrimethanil allowed lower germ tube growth of P. fijiensis ascospores in all three BPUs, resulting in higher germ tube inhibition efficacy than the other fungicides.