|DAVIDSON, JENNY - South Australian Research And Development Institute|
|GOSSEN, BRUCE - Agriculture And Agri-Food Canada|
Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: 4/20/2020
Publication Date: N/A
Interpretive Summary: Ascochyta blight is a serious disease of pea worldwide. The disease is caused by four related pathogen species. The disease afects all above grand part of pea plants and causes significant yield losses under conducive conditions. This chapter describes the distribution, symptoms and pathogens of Ascochyta blight of pea. Photographic illustrations are provided and management options are recommended.
Technical Abstract: Ascochyta blight of pea is a serious yield constraint of pea worldwide. It is caused by four related necrotrophic pathogens: Ascochyta pisi, Ascochyta koolunga, Didymella pinodes, Didymella pinodella, The pathogens causes necrotic lesions on leaves, stems, flowers, pod and seeds under cool and humid conditions. All the pathogens, except A. pisi, survive in the soil for a number of years as chlamydospores, mycelium, sclerotia or pseudosclerotia. Inoculum from soil is particularly important in established pea growing areas where soil-borne inoculum builds up under successive pea crops. All the pathogens can be seed transmitted, resulting in infection on the basal plant parts. Conidia are produced by all of the causal pathogens. Primary inoculum of all of the causal pathogens is spread by wind (sexual ascospores) or rain splash (asexual conidia) onto field pea crops. Only D. pinodes is recorded to produce ascospores in the field. Partial resistance to the disease is available. Resistance is quantitative and affected by the environment, including leaf age, inoculum concentration and temperature. Since major gene resistance is not available, disease control often relies upon management strategies that avoid inoculum sources.