OBSERVATIONS ON APPLE CANKER

I. THE DISCHARGE AND GERMINATION OF SPORES OF NECTRIA GALLIOENA BRES.

Authors


  • Read before the Association on 9 December 1938.

Summary

  • 1The fungus causing apple canker is described and its identity with Nectria galligena Bres. is confirmed.
  • 2The methods of dispersal of the spores of Ngalligena have been examined. The ascospores are discharged forcibly from the perithecium, the eight spores of each ascus typically being ejected simultaneously.
  • 3Field investigations have shown that spores are discharged during wet periods at all times of the year. Ascospore discharge reaches its maximum in January-February and falls to a minimum in the summer months.
  • 4The dispersal of conidia occurs during wet periods in the spring and autumn.
  • 5Germination both of ascospores and conidia occurs over a range of temperature from 2 to 30°C, the optimum being at 20°C.

Ancillary