Comparison of Different Fungicides for Control of Downy Mildew of Broccoli -- 1991 Field Trial

Downy mildew of broccoli, caused by the plant pathogenic fungus Peronospora parasítica, can be found every year in many broccoli fields in Arizona. The severity of the disease is affected by the occurrence and duration of weather conditions favorable for disease development. During the 1990-91 vegetable season in western Arizona, different fungicides and rates of materials were evaluated in the field for disease control. Ridomil /Bravo and Bravo, which are currently registered for use on broccoli to control downy mildew, and Aliette, which is currently not registered for use on this crop, provided significant disease control compared to untreated plants. Rovral and Topcop did not control downy mildew on broccoli.