Alternative oxidase reduces the sensitivity of Mycosphaerella graminicola to QOI fungicides.

Forty-six (1.5%) of nearly 3000 isolates of Mycosphaerella graminicola assayed in vitro were resistant to the QOI fungicide azoxystrobin, but on sub-culturing only ten remained resistant. Cross-resistance extended to other QOIs, but varied between different isolates.