The Effect of Temperature and Nutrients Upon Spore Germination of the Oak Wilt Fungus

SUMMARY

The optimum temperature for the germination of ascospores and endoconidia of E. fagacearum is within the range of 21° to 32° C; the maximum is between 33° and 36° C; and the minimum is below 3° C. The time required for the spores to germinate, the rate of growth of germ tubes and the production of secondary endoconidia were affected by temperature. Exposure to 36° C for 34 hours and to 40° C for 24 hours killed the endoconidia and ascospores.

Sucrose, glucose and yeast extract permitted high percentage germination; however, the spores germinated fairly well in rain water and distilled water. Decoctions and infusions of living and dead red oak bark and wood and various mixtures of these solutions allowed increased germination over germination in distilled water.