Effects of temperature on development and progression in rape of crown canker caused by Leptosphaeria maculans

Abstract

Aspects of the development and progression of blackleg crown canker in rape seedlings (Brassica napus and B. campestris), following stem infection by L. maculans ascospores were examined at three temperature regimes; 12/7�C, 18/11�C, and 24/15�C. Crown cankers were produced at all temperatures on seedlings inoculated one week after germination. Temperature regime was shown to be a major factor determining the time of first appearance of crown cankers after inoculation; 12/7�C being the least favourable for crown canker development of the three regimes used. Temperature regime had a significant effect upon the time taken for infected plants to die, the 12/7�C regime being the optimum for slowest plant death, Infected B. napus plants died at a faster rate than B. campestris. Temperature regime was also shown to influence the nature, or type, of crown canker that developed.