Weekly Field Update – 7/18/22

Check out Clemson Extension’s new weather data website! Last week, state weather station technician Christopher Thomas introduced the new site at the Watermelon Field Day at the Edisto REC. Christopher has been working hard installing weather stations in all 46 counties of South Carolina over the last year. Eventually, the site will be able to give reports on historical weather data to help growers make better planting, harvesting, and disease management decisions.

A big congratulations to Sidi Limehouse of Rosebank Farms for winning the SC Big Melon Contest at the Edisto REC Field Day this past Thursday. Sidi weighed in a 124-pound melon. This was the inaugural SC Big Melon Contest, and we hope to keep this event going for years to come. Start preparing for next year’s contest…Sidi says, “I would like some good competition next year.”

Be sure to scroll all the way to the bottom to see this week’s Question of the Week and check back on Thursday for the answer!

Statewide

Plant Pathologist Tony Keinath reports, “With the wet weather the past 2 weeks, gummy stem blight is spreading rapidly on watermelon. Because of widespread resistance to tebuconazole and the need for systemic fungicides, growers should rotate Miravis Prime with Inspire Super until harvest is finished.”

Gummy stem blight symptoms on watermelon leaves. (T. Keinath)

Coastal Region

Rob Last reports, “With increasing rainfall, disease pressure is building rapidly in crops. Gummy stem blight is very active in cucurbit crops. As we approach the end of the picking season in places, it is still important to maintain fungicide programs up to 1 week of harvest. Once harvest is over, prompt destruction of the previous crop residue will also be important to help reduce inoculum levels for fall crops. Downy mildew is active in most cucurbits, and we are finding anthracnose in tomatoes, peppers, and eggplant. Insect activity is also increasing in crops from aphids, cucumber beetles, armyworms, and stink bugs. While a pyrethroid may be the more inexpensive application initially, reducing beneficial insects can be more costly in the long term. Selective products, while more expensive initially, may help preserve beneficial insect populations. The net result in the longer term is an increase in sustainability.”

Zack Snipes reports, “It seems like it rains every afternoon lately. Fields are sloppy wet. Those that aren’t finished up will be by week’s end. For those growers out there that aren’t planting fall crops, it is extremely important to mow your fields, get the plastic out, and get the field disked up or planted with a cover crop. Leaving crop residue in fields post-season can really build up populations of pathogens, insects, weeds, weed seeds, and nematodes.”

Orange Cane Blotch on blackberry. I’ve yet to see a field without this disease in the Lowcountry. (Z. Snipes)

Midlands

Justin Ballew reports, “While the forecast showed a good chance of rain every day last week, we didn’t receive nearly as much as the week before. What we did get was very scattered. The temperatures were a little cooler, but it has been humid. We’re still seeing plenty of disease. Powdery mildew has exploded in some cucurbit crops. Growers are managing it the best they can, but all the moisture and humidity we’ve been having is making it tough. Some green peanuts were dug this week, and folks are still finishing up with spring crops. Lots of field prep for fall crops happening now.”

Small, yellow spots on a watermelon leaf from powdery mildew. (J. Ballew)
Freshly dug green peanuts. (J. Ballew)

Sarah Scott reports, “Temperatures have been cooler, and we have still been getting rain in the area. Growers are harvesting varieties like Julyprince and Scarletprince. Both of these varieties performed well and were not hit as hard with cold damage, so there are a lot of peaches right now. Scale crawlers are our, but the population does not seem to be crazy right now.  Disease issues have been hit or miss, but we will monitor this closely with all of the wet weather. 

Nice-looking peaches are coming out of the Ridge. (S. Scott)
Bacterial spot is heavy, in spots, in highly susceptible O’henry. (S. Scott)

Question of the Week

For this week’s question, take a look at the photo below. What’s going on with this watermelon?

Answer in the comments below and check back on Thursday to see the answer.

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