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Poster: Biology & Disease Mgmt: Integrated Pest Mgmt


Evaluation of the weather-based spray advisory program MELCAST, fungicide alternations and mulch to manage watermelon diseases in Missouri
Z. MERSHA (1), M. O'Connor (1) (1) Lincoln University - MO, U.S.A.

Melons are economically important crops in Missouri. Each year, Alternaria leaf blight (ALB), anthracnose (ANT) and gummy stem blight (GSB) cause yield losses in melons. Most commercial growers use calendar-based fungicide spray schedule. MELCAST (MELon disease foreCASTer) is a weather-based disease-forecasting and spray advisory program that allows cantaloupe and watermelon growers to schedule sprays based on weather. From 2013–2015, there were 3-6 MELCAST sites in central, east and south east Missouri. Research plots were established at one of the sites in central Missouri at G. W. Carver Farm to examine MELCAST, mulches and fungicides in reducing diseases of watermelon using variety ‘Crimson Sweet’. Fungicide sprays significantly (P<0.05) reduced diseases compared to non-sprayed plots. Alternating Bravo WeatherStik and Inspire Super or Quadris Opti and Luna Experience significantly reduced ALB, ANT and GSB. No significant difference was detected between these two plans. In 2014, total foliar biomass was significantly (P<0.05) higher with fungicide sprays (34.7 lb/plot) than without (9.1 lb/plot) for the plastic mulch plots. Disease suppression was not significantly different either between MELCAST and weekly sprays or between rye-vetch and plastic mulch. Use of MELCAST saved 1-2 fungicide sprays per season. Growers are encouraged to use mulch and to alternate fungicides in order to overcome risk of fungicide resistance and to improve productivity of watermelons.