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Evaluation of a Warning System for Early-Season Control of Grapevine Powdery Mildew

January 2012 , Volume 96 , Number  1
Pages  104 - 110

Tito Caffi, Sara E. Legler, and Vittorio Rossi, Università Cattolica del Sacro Cuore, Institute of Entomology and Plant Pathology, I-29122 Via E. Parmense 84, Piacenza, Italy; and Riccardo Bugiani, Plant Protection Service, Regione Emilia-Romagna, Bologna, Italy

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Accepted for publication 22 August 2011.

In several grape-growing areas of the world, including northern Italy, powdery mildew epidemics, caused by Erysiphe necator, are mainly triggered by the ascospores produced in overwintered chasmothecia. Growers in northern Italy usually control the disease with fixed-interval fungicide applications. A warning system was developed for early-season powdery mildew control based on (i) short-term weather forecasts, (ii) a model that simulates the severity of each E. necator ascosporic infection, and (iii) a mobile phone short-message system. This warning system was evaluated in six vineyards in northern Italy from 2006 to 2008, between bud break of vines and early berry development; an unsprayed control was compared with “low-risk” and “high-risk” model-driven sprays and a calendar-based “grower” spray program. Use of the warning system reduced disease severity on leaves and bunches compared with the unsprayed control and resulted in the same level of control of powdery mildew as the grower's spray program, with reduced fungicide applications and costs. On average, 5.7 sprays were applied following the grower's spray program (with an average cost of 221 €/ha/year); use of the warning system reduced fungicide applications by 36% (low-risk program, saving of 56 €/ha/year) or 75% (high-risk program, saving of 161 €/ha/year).

© 2012 The American Phytopathological Society