University of Hertfordshire

By the same authors

View graph of relations
Original languageEnglish
Number of pages6
Publication statusPublished - Aug 2013
Event11th International Epidemiology Workshop - Beijing, China
Duration: 22 Aug 201325 Aug 2013

Conference

Conference11th International Epidemiology Workshop
CountryChina
CityBeijing
Period22/08/1325/08/13

Abstract

Phoma stem canker is a major disease problem on winter oilseed rape (Brassica napus) in the UK. The disease is caused by two closely related species, Leptosphaeria maculans and L. biglobosa. Previous epidemiology work has focused on L. maculans and there is little information on L. biglobosa. Because L. maculans is often associated with stem base canker while L. biglobosa is often associated with upper stem lesions, L. maculans is considered more damaging than L. biglobosa. Both L. maculans and L. biglobosa are present in the UK. To control the disease effectively, it is necessary to understand the epidemiology of both pathogens. This presentation reports studies on these two related species at different stages of their life cycles. Results show that there are differences between these two species in their biology and epidemiology, which enable them co-exist on the oilseed rape crop. There are differences between L. maculans and L. biglobosa in pseudothecial maturation. Pseudothecia of L. biglobosa mature more slowly than those of L. maculans at 5-10°C; pseudothecia of L. maculans are mainly produced on the surface of stem bases, pseudothecia of L. biglobosa are mainly produced under epidermis of upper stem. The differences in pseudothecial maturation between L. biglobosa and L. maculans result in differences between them in timing of ascospore release and thus in the timing of the resulting phoma leaf spot lesions in autumn. Ultimately, there are differences in timing and severity of stem cankers the following summer. The differences in biology and epidemiology between these two species at key stages of their life cycles, such as initial leaf infection, asexual production, subsequent stem canker development, survival and sexual production on crop debris will be discussed.

ID: 7168279