Some observations on the economic importance of sugar‐beet downy mildew in England

Abstract

SUMMARYSugar‐beet downy mildew is most prevalent in England in the sugar‐beet and mangold seed‐growing area of South Lincolnshire and West Norfolk. The most widespread and severe recent outbreaks were in 1957, and in 1965 when 6412 acres were reported with more than 10% infected plants. The fungus usually overwinters in sugar‐beet and mangold seed crops, and in England other ways of overwintering are seldom important. Steckling beds are infected in the autumn, and the disease may increase rapidly in the seed crop in early spring. Summer‐sown stecklings get more downy mildew than stecklings sown in spring under a cereal cover crop, and direct‐drilled seed crops get more downy mildew than transplanted crops.