The Effects of Temperature and Relative Humidity on Germination of Spores of a New Zealand Isolate of Dothistroma Pini Hulbary

Abstract

Two New Zealand isolates of Dothistroma pini Hulbary have been studied. Sporulation was best on 3% malt extract agar although good growth occurred on potatoes dextrose agar and V-8 juice agar. Spores germinated at temperatures between 5 and 30°C. with an optimum at 17°C. Liquid water was not necessary for spore germination. Germination was severely inhibited at humidities as low as 76% R.H. The fungus studied appeared to be more-closely related to D. pini var. kiniensis than to the other two varieties described for Kenya, but further work is necessary before the varieties present in New Zealand can be determined with certainty.