Erysiphe pisi var. pisi on faba beans and other legumes in Britain

Abstract

The powdery mildew Erysiphe pisi var. pisi, complete with its teleomorph, has been observed on faba beans (Vicia faba cultivars) for the first time in Britain. It appeared in a glasshouse on Syrian lines of fodder bean and English cultivars of broad bean. It also infected tare (Vicia sativa) and sweet pea (Lathyrus odoratus), but not edible pea (Pisum sativum), ornamental lupin (Lupinus polyphyllus), French bean (Phaseolus vulgaris) or sainfoin (Onobrychis viciaefolia). Inoculations in a glasshouse showed that another strain of E. pisi var. pisi found on outdoor everlasting pea (Lathyrus latifolius) was also capable of affecting faba bean, and was distinguished by its ability to infect edible pea. A third strain found on outdoor ornamental lupin infected only lupin. E. pisi var. pisi was shown to be morphologically and pathogenically distinct from the Erysiphe sp. newly affecting tomatoes in Britain.