Comparison of Fungicides for Management of Downy Mildew of Broccoli in 2003

Abstract

Downy mildew of broccoli, cauliflower and cabbage is caused by the oomycete pathogen Peronospora parasitica. Cool moist environmental conditions favor the development of downy mildew on these crops. Several potential new fungicides were evaluated for control of this disease on broccoli in 2003. A moderate level of disease had developed by crop maturity. Actigard, Actigard alternated with Quadris, Acrobat+Maneb and DPX-KP481 were among the best treatments in this trial. Actigard is not a fungicide, but is classified as a plant activator. When applied to plants, this compound stimulates a defense response in plants to some diseases. Actigard also has performed well in previous trials. Several other new products and some chemistries that are currently available provided significant levels of disease control as well.