Resumo

RUIZ-SANCHEZ, E. et al. Systemic fungicides evaluation for downy mildew control (Pseudoperonospora cubensis Berk. & Curt.) Rost. on cantaloupe melon (Cucumis melo L.). Rev. Chapingo Ser.Hortic [online]. 2008, vol.14, n.1, pp.79-84. ISSN 2007-4034.

The effectiveness of four systemic fungicides (azoxystrobin, 150 g·ha^-1; dimethomorph, 225 g·ha^-1; fosetil-Al, 2 kg·ha^-1; y triforine, 285 g·ha^-1) for downy mildew control (Pseudoperonospora cubensis) was evaluated in cantaloupe melon early sown at the Yucatan State, Mexico. The fungicides were sprayed at 36, 52 and 67 days after transplant (dat), and the disease intensity at 43, 60, and 75 dat, yield components, and fruit soluble solids concentration, were assessed. No significant difference on disease incidence (5.6-12.5%) was observed at 43 dat. Disease incidence (73.3%) on dimetomorph treated plots was significantly lower than in the control plots at 60 dat. Disease incidence reached 100% in all treatments in the last recorded date, 75 dat. Disease severity, measured with Horsfall-Barratt scale, was significantly lower in dimetomorph treated plants in the three dates evaluated. The final disease severity was significantly lower in plants treated with dimetomorph or fosetil-Al, in which 85 and 75%, respectively, less area under the disease progress curve (AUDPC) was observed than in the control plants. These fungicides also induced the highest number of fruits per plot, mean individual fruit weight, and total fruit yield. The fruit soluble solids concentrations were not significantly different among treatments. A linear negative effect (r²=0.84) of the disease severity (AUDPC) on the total fruit yield was found.

Palavras-chave : cucurbits; severity; incidence; area under disease progress curve (AUDPC).

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