Chuck Bornt, Senior Extension Associate, CCE Eastern New York Commercial Horticulture Program
If you are growing cantaloupes, cucumbers or any other kind of vine crop, you know that Cucurbit Downy Mildew has become an annual pest that we have to deal with. In the last few years, a lot of effort has gone into breeding varieties of melons and cucumbers that have CDM resistance. Cornell University’s Vegetable Plant Pathologist Dr. Margaret McGrath has been evaluating several cantaloupe varieties along with Integrated Pest Management fungicide programs targeting CDM. Since it’s the season we are all pouring over our seed catalogs, I thought sharing Dr. McGraths article, “Evaluation of Downy Mildew Resistant Cantaloupe Varieties in an Integrated Program with Fungicides Applied on an IPM Schedule, 2022 Results” would be timely.
This research follows a 2021 cantaloupe variety trial in which the varieties Trifecta and Edisto 47 showed good control of downy mildew and also powdery mildew, but did not provide enough protection against downy mildew to eschew fungicide treatment during downy mildew season. Research indicates that an IPM approach to these resistant varieties is the best way to manage downy mildew. In 2022, Dr. McGrath tested these varieties, along with a susceptible variety (Ambrosia) and a third resistant variety, Planter’s Jumbo, to determine if downy mildew could be managed by applying the conventional weekly program of targeted fungicides applied on an IPM schedule, and how effective this method was for resistant varieties.
The results are summarized as follows:
- Similarly excellent control was achieved with a conventional fungicide program applied starting after symptoms found (IPM schedule) to the resistant varieties Trifecta, Edisto 47, and Planter’s Jumbo as well as susceptible Ambrosia.
- Genetic downy mildew resistance provided moderate suppression (29%) based on comparison of untreated Trifecta and untreated Ambrosia.
- Trifecta was the best variety in this experiment based on its fruit having highest sugar content (Brix) and highest average ratings for taste, texture, and internal appearance.
Dr. McGrath’s researched can be found in full at the following links: