Effect of trifloxystrobin and azoxystrobin on the control of black Sigatoka (Mycosphaerella fijiensis Morelet)on banana and plantain

Trials to determine the efficacy of trifloxystrobin (75 and 100 g ai/ha)and azoxystrobin (100 g ai/ha), on the control of black Sigatoka disease caused by Mycosphaerella fijiensis Morelet (M. fijiensis), in small randomized plots of banana and plantain treated from the ground and in commercial banana fields treated from the air, were carried out between 1997 and 1999. Trifloxystrobin at 75 g ai/ha showed a similar efficacy to propiconazole at 100 g ai/ha and benomyl at 150 g ai/ha and was superior to azoxystrobin (100 g ai/ha). Azoxystrobin show a similar efficacy to propiconazole against M. fijiensis populations sensitive to DMIs. The ED50 (ascospore germinative test)of five wild type M. fijiensis populations of different localities to azoxystrobin were between 0.03 and 0.8 mg/ml. Results suggest that monitoring for strobilurin resistance may be conducted using 5 mg/ml as the threshold concentration.