Weekly Watermelon Update – June 3

Bob Hochmuth, Regional Specialized Extension Agent- Vegetable Crops, with input from Suwannee Valley Extension Agents: Mark Warren (Levy), Tyler Pittman (Gilchrist), Tatiana Sanchez (Alachua), Luke Harlow (Bradford), Dan Fenneman (Madison), Keith Wynn (Hamilton), Emily Beach (Lafayette), Jim Devalerio (Union), De’Anthony Price (Jefferson), Raymond Balaguer(Suwannee), Kevin Athearn (RSA-Agri- business), Shivendra Kumar (RSA-Agronomic Crops), and Jay Capasso (RSA- Water Resources)

Disease Update

Well, there is not much new to report, except that this past week we saw gummy stem blight continue to be very difficult to control. There is plenty of disease pressure and from several pathogens, but by far, gummy stem blight is causing the greatest concern. Downy mildew and powdery mildew are relatively easy to find in some fields, but grower spray programs seem to be working much better on downy mildew and powdery mildew.  Many farmers are reporting using the maximum amounts of both Inspire Super (Group 9 and 3) and Aprovia Top (Group 7 and 3). Both of these materials have similar Group 3 chemistries, so the only other option for a rotation after these two with some level of control of gummy stem blight may be Switch. So, the bottom line is that gummy is appearing to be very difficult this year. This difficulty in “running out” of options points back to the importance early in the season to stay with chlorothalonil (Bravo and others) and mancozeb (Manzate and others) as long as we can. If you switch away from them too early, you set up the situation for certain Groups of chemistries to be “used up” with maximum amounts per season.

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If you plan to keep fields going for two or more weeks, I suggest you keep up with a good fungicide program. Once you get near that final cutting, you can greatly reduce your investment.

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If you know someone who wants to be added to this weekly notice, contact your Extension Agent or Mark Warren (352-949-8288) if you want to be added to the regional watermelon group text app.

We have initiated a more formal way to support our watermelon growers with a rapid diagnostics system through Suwannee Valley Regional and County Extension Agents. This industry-funded program allows Extension Agents to submit and pay for watermelon grower’s plant disease and other diagnostic samples. This SV Rapid Diagnostic Watermelon Program will help us to get quicker diagnostic results, helping to give early alerts to everyone, and not have to charge the growers directly. Plant disease samples are typically $40 and leaf tissue analyses are typically $20. We are currently extending our solicitation of those industry reps interested in sponsoring this effort. The past year’s sponsorships have ranged from $200 to $2,000 per company. Sponsors will be recognized every week beginning this week. Those interested in being added as a sponsor can contact Bob Hochmuth at bobhoch@ufl.edu or 386-288-6301.

Current 2024 sponsors of our Watermelon Rapid Diagnostics Program include Valdosta Plant Company, Mayo Ag Services, Gowan USA, Harrell’s Fertilizer, Triest Ag, Syngenta Crop Protection, WestRock Paper Company, Orbia Netafim, and Super Sweet Farms. Others are still welcome to join.