Crops Update: Clemson Extension Agents Provide Updates Across State

Clint Thompson South Carolina, Top Posts

Clemson Extension agents provide updates in the The South Carolina Grower this week about the status of various crops being produced throughout the state.

Coastal

Rob Last reports, “As we mentioned last week, cucurbit downy mildew has been confirmed in cucumber crops locally. All cucurbit growers should be applying downy-mildew specific fungicides, such as Ranman tank mixed with either chlorothalonil or mancozeb. Other pests and disease levels in cucurbits remain low. Tomatoes and peppers are developing well with good fruit development and low pest and disease pressure. A little bacterial spot is beginning to show in untreated crops. Applications of mancozeb or copper can help to hold the disease. Note: applications are unlikely to “cure” bacterial disease. Fruit crops continue to progress with good quality and low disease. Strawberries are showing a little botrytis and anthracnose, but this is at a low level. Peaches are coming to market along with blueberries and blackberries.

Midlands

Justin Ballew reports, “Dry weather has returned to the midlands. Strawberries have slowed down, and while we’re still picking a few, we are seeing very few blooms. The heat we’re expecting this week is likely to cease bloom production. The heat could be a problem for tomato and cucurbit pollination as well, as we may see some blooms die. Brassicas have been growing well. There has been an increase in diamondback moth activity over the last week. If you start seeing large DBM (diamondback moths) populations on your farms, contact your local agent about doing a bioassay to test for insecticide resistance. This is a great way to figure out which materials may work best on your farm. We don’t charge anything for this service. Don’t forget downy mildew was found this past week in cucumber in multiple places in the coastal plain, so it’s time to start preventative fungicide sprays in cukes if you haven’t already.”

An adult diamondback moth has just finished pupating and has not yet dispersed. Remember, insecticide applications should target the larval form rather than the moths. Photo from Justin Ballew

Sarah Scott reports, “We are in full swing with early variety peach harvest. Some peaches are developing a little smaller in size partly due to previous cold weather events. Something spotted in the field has been some nutrient deficiency. Growers may have been tempted to dial down nitrogen or calcium nitrate applications on peach blocks that suffered cold damage, as they thought those blocks would not produce a viable harvest. However, this could lead to leaf drop and less reserves for next year’s crop. If you skipped out on some of your fertilization, keep in mind yellowing, spotting and leaf drop could occur. A soil application of calcium nitrate at 30lb/acre now and another in late July can help those trees recover some foliage and build up a nutrient supply for next year’s reserve. Be careful if you want a quick result and try foliar applications, as this could burn the leaves and cause more drop that you may not be able to afford.”

Nitrogen deficiency on a mid season peach variety. Photo from Sarah Scott
Discoloration from nitrogen deficiency looks similar to copper burn but has smoother edges and more rounded spots on leaves. A nutrient analysis can be taken around July to determine accurate levels. Photo from Sarah Scott.

Pee Dee

Bruce McLean reports, “Irrigated vegetables are looking good for the most part. Seeing some stress to tomatoes with a heavy fruit load – likely from very low humidity and very high UV. Non-irrigated crops are starting to show some drought stress. Strawberries are starting to wind down. Blueberries are finally starting to be harvested, much later than usual. Blooming on muscadines appears to really stretched out due to the Easter freeze. Early flower clusters on growth from primary buds appears to be somewhat on time. But flower clusters developing from secondary buds are really behind… possibly 3-to-4 weeks (easily). Soil is really starting to get dry in many areas.”

Green beans are really coming along. Photo from Bruce McLean
Now is a good time to walk the fields and pull weeds. Over-the-top herbicides are limited for most vegetable crops, and often hand weeding is the only viable option. Vigorous weeds like pigweed can quickly overtake a field. Photo from Bruce McLean.

Tony Melton reports, “The higher temperatures have started to speed up crops. We will start to harvest pickles this week. Spraying downy mildew fungicides on cucurbits. Some farmers are starting to apply insecticide for pickleworm. They don’t want to put out insecticides this early, but they see the gamble of an entire field of pickles being rejected because of one pickleworm as too much of a gamble. These farmers think we need a system set-up to detect pickleworm in the southern part of the state to give them a better indication of when pickleworm arrives. Harvesting greens, cabbage, and broccoli as quickly as possible. Started planting sweet potatoes. Many farmers getting deer depredation permits for peas, beans and sweet potatoes. Also, many farmers are applying acephate and dimethoate to control thrips with the added benefits of repelling deer. Peppers and tomatoes are begin to load with fruit. Many farmers still harvesting strawberries.”

Upstate

Kerrie Roach reports, “Things in the ‘Golden Corner’ are looking up for vegetable producers, despite the dismal projection for tree fruit crops because of the cold events in April. For market growers, cool season crops are at their absolute last with 90-plus degree temps forecasted for this week. Warm season crops are starting to really get growing, and many growers are starting to see some potential harvests this week. With higher than normal temps projected, make sure irrigation is consistent, scheduled and set for early morning to avoid leaf wetness late in the day and overnight, and reduce disease incidence.”