On August 17, 2017, University of Illinois pumpkin expert Mohammad Babadoost detected downy mildew in a pumpkin field in St. Anne, Illinois (Kankakee County), and warns that it could spread quickly.

Babadoost, a plant pathologist in the Department of Crop Sciences at U of I, observed heavy sporulation of the pathogen on leaves in the affected field. "With current weather conditions, the pathogen could spread very fast and affect all cucurbit crops," he says.

Farmers can protect cucurbit crops by applying fungicides, according to Babadoost.

"I suggest the following fungicides for control of cucurbit downy mildew in Illinois: mandipropamid (Revus, FRAC: 40) + chlorothalonil (Bravo Weather Stik, FRAC: M), alternated with oxathiapiprolin + chlorothalonil (Orondis Opti, FRAC: U15 + M) or cyazofamid (Ranman, FRAC: 21) + chlorothalonil (Bravo Weather Stik) or fluazinam (Omega, FRAC: 29)," he says.

As always, label recommendations, particularly pre-harvest interval (PHI), should be carefully considered when applying fungicides.