Effect of temperature, osmotic potential and pH on the growth of the turf pathogens Gaeumannomyces wongoonoo and Magnaporthe griffinii
The effects of temperature, osmotic potential and pH on the linear growth rates of two isolates of Gaeumannomyces wongoonoo and three isolates of Magnaporthe griffinii were studied. G. wongoonoo and M. griffinii grew maximally at 20-25°C and 25-30°C, respectively, which may explain their disease activity in the field from late spring to mid-autumn. The growth rate of G. wongoonoo was more than halved at about 15°C, and growth ceased at 10°C. Growth of M. griffinii was negligible at 15°C and ceased at 10°C. There was negligible growth of both fungi at 35°C. In response to osmotic potential, G. wongoonoo grew maximally at an osmotic potential of -0.12 MPa, while M. griffinii grew fastest at -1.0 to -2.0 MPa depending on the isolate. The growth rates of both fungi decreased linearly as the osmotic potential decreased, that of G. wongoonoo and one isolate of M. griffinii being minimal at -5.0 MPa, while the other two isolates of M. griffinii were capable of growth at -6.0 MPa, albeit very slowly. In response to pH, G. wongoonoo grew maximally at a pH 6.5-7.0, and the growth rate was halved at pH 5.0. In contrast, all three isolates of M. griffinii grew maximally at pH 5.0 and their growth rates were more than halved in the alkaline range (pH 7.0-8.0). These in vitro results provide a basis for more research into the activity of these fungal pathogens in field situations.
Evans, B.J., Wong, P.T.W. and Martin, P.M. (2016). Effect of temperature, osmotic potential and pH on the growth of the turf pathogens Gaeumannomyces wongoonoo and Magnaporthe griffinii. Acta Hortic. 1122, 49-54
turfgrass, Magnaporthe griffinii, Gaeumannomyces wongoonoo, temperature, osmotic potential, pH