Clemson Extension Agents Provide Crop Updates

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

Statewide

Dr. Matt Cutulle reports, “With all the rain we had in August the weed seed bank is starting to pop. Nutsedge pressure can be really tough in September. For fall cole crop plantings, it is important to initiate the stale seed bed technique (allow weeds to come up and burn them down multiple times before planting). In some cole crops, such as broccoli, Dual Magnum may be used, which provides some pre-emergent suppression of yellow nutsedge (max 60% probably). Following with an in-row cultivation several weeks after planting will strain the photosynthate reserves of nutsedge, which could be lethal to the nutsedge if we get a cold snap in late October.”

Coastal

Zack Snipes reports, “I saw whiteflies everywhere last week. I saw them on just about every crop in the field: squash, zucchini, tomato, peas, eggplant, okra. We have very good options to manage whiteflies so consult with your local agent or look up the specific products for the crop you are growing in the Southeast Crop Handbook. Be careful not to use pyrethroids for whiteflies, as resistance will develop very quickly. Longer lasting, more specific options are available that are better options. I also saw a good many worms last week such as the melonworm in cucurbits and the beet armyworm in other crops.  If you have whiteflies and worms in a crop then the group 28 insecticides (Coragen, Verimark/Exirel, Harvanta) are excellent options to take care of both pests at the same time with good residual.”

Whitefly infestations are severe in some places on the Coast. Photo from Zack Snipes.
Whiteflies on tomato leaves. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Last week was extremely hot and dry, though we finally got some relief from the heat over the weekend. Crops are progressing well, though we are seeing caterpillar activity increase. We’re seeing diamondback moth and cabbage loopers in brassica crops and armyworms in tomatoes. Be sure to rotate insecticide MOA’s when treating for caterpillars. I’m also seeing a few whiteflies around but nothing severe yet. Black rot is starting to show up on some brassicas. Strawberry growers are starting to apply their pre-plant fertilizers in preparation for shaping the beds.”

Black rot getting started on a young collard plant. Photo from Justin Ballew

Pee Dee

Bruce McLean reports, “Muscadine harvest is starting to wind down. Harvest looked good and had very good yields. Brix averaged out at 13.5% to 14.5%, depending upon the cultivar and the vineyard. Now is a good time to evaluate successes and problems from this season and write them down while they’re fresh on your mind. Also, look at the overall amount of foliage on the vines. Is it too much? Not quite enough? Start planning how you need to adjust fertility for next year. A post-harvest potassium fertilizer application has proven to be beneficial to the crop (in on-farm settings), especially in wet years. Overall plant health, spring emergence and vigor, and next year’s yields should be well improved.”

A bin of Carlos muscadines ready to be loaded and delivered for processing. Photo from Bruce McLean.

Tony Melton reports, “Getting dry and need some rain. Busy planting turnips, mustard and collards. Harvesting processing sweet potatoes as quickly as they can process them (problems in the plant). Picking pickles and yielding much better with dryer conditions. Also, pickling plants having trouble with getting enough labor so very few peppers harvested. Still spraying processing peas for cowpea curculio. Watch out for southern stem blight. It is still raging havoc.”

Upstate

Kerrie Roach reports, “The last few peaches are making their way to stands and markets. Things are continuing to look good as the apple crop progresses in the upstate. Growers to the north in Hendersonville, North Carolina suffered multiple hail events, causing a large amount of damage, but South Carolina growers seem to have escaped the worst of it. Vegetable production has slowed significantly with many small growers finishing for the season over the next few weeks. Muscadines are coming into their prime and look to be highly productive this year.”

Golden Delicious apples that still have a little ways to ripen for optimum sugar content, but work great for baking. Notice the green tint. As they continue to ripen, a yellow cast & even a blush may appear. Photo from Kerrie Roach.

Andy Rollins reports, “These plants were found positive for Phytopthora root rot last week in an early upstate strawberry planting. Inspection of plants when they arrive can accurately diagnose this problem. Brown to blackish colored roots are characteristic. A small portion of this material is taken from 5 to 10 plants then placed into a pouch that accurately identifies the presence of Phytopthora within a few minutes. As in picture, one line tells you the test worked properly and two lines indicates presence of the fungus.  Early treatment with Ridomil and or any of the phosphite (Rampart/Prophyt) is very helpful but must begin quickly if plants are widely infected for the best results.”

Dark colored roots are a characteristic symptom of Phytophthora root rot. Photo from Any Rollins.
An immunostrip test can be used to diagnose phytophthora. Two horizontal red lines on the strip (right side of the bag) means the sample is positive for phytophthora. Photo from Andy Rollins.