Comparison of compounds for management of powdery mildew on casaba melon in Imperial County, California

• Published in: Phytopathology Vol. 95; no. 6
• Main Authors: Turini, T, Aguiar, J
• Format: Journal Article
• Language: English
• Published: 01.06.2005
• Subjects: Podosphaera xanthii; USA, California
• ISSN: 0031-949X

Efficacy of fungicides against Podosphaera xanthii, the fungus that causes cucurbit powdery mildew, was evaluated in the field from 2000 to 2004. During this five year period, quinoxyfen and triflumizole reduced disease severity, as determined by the portion of upper leaf surface with powdery mildew colonies, by more than 90% compared to untreated plants. Wetable sulfur provided 70 to 80% reduction in disease severity. Myclobutanil reduced disease severity by only 71% in 2000, but reduced disease by more than 80% from 2001 to 2004. Trifloxystrobin was one of the best performing materials in 2000 and 2001 with more than 90% disease severity reduction but only 27 and 41% in 2002 and 2003, respectively. Azoxystrobin and pyraclostrobin provided over 70% disease reduction in 2001. In 2002 and 2003, azoxystrobin reduced disease by 39 and 40%, respectively and pyraclostrobin reduced disease by 27 and 37%. In 2004, trifloxystrobin, azoxystrobin and pyraclostrobin reduced disease severity by 79, 68 and 57%, respectively.