Weekly Field Update – 9/8/20

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 preplant 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, NC suffered multiple hail events causing a large amount of damage, but SC 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 5-10 plants then placed into a pouch that accurately identifies the presence of Phytopthora within a few min.  As in picture, 1 line tells you the test worked properly 2 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.

Field Update – 7/27/20

Coastal

Zack Snipes reports, “It has been a hot week in the Lowcountry. Most spring and summer crops have finished up. Ground is being prepared and planted for fall crops. I have received a few texts from growers that have yellow dots on their zucchini plants, which is downy mildew. Even in this heat downy can still be an issue. I have also had some reports of green-colored squash in fields which is an indication of a viral pathogen. The crop handbook has recommendations for cultivars that are resistant to these viruses that cause this discoloring. Fall is notoriously bad for cucurbit viruses so plan accordingly.  I have also seen some flea beetle damage on crops as of late.”

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Downy mildew looks a little different on zucchini and pumpkin than it does on cukes. Photo from Zack Snipes.

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Flea beetle feeding damage on blackberry foliage. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “It’s been hot in the midlands and we’ve gotten to the point where there isn’t much relief at night. We had some scattered rain throughout the week, but overall we’re still quite dry. Lots of land is still being prepped for fall crops. We’ve had some fall brassicas and cucurbits planted already and they’re looking good so far. Last week I got to watch a pecan grower in Lexington thin some pecan trees. Without thinning, he would have seen a massive yield this year, which would result in a significantly diminished yield next year. Pecan growers aim for nuts on just 70% of the terminal buds.”

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Fall squash seedlings just beginning to emerge. Photo from Justin Ballew

Thinning pecans with a mechanical shaker. You can see the nuts fall as the tree vibrates.

Pee Dee

Tony Melton reports, “Pickles are still being harvested and planted. We still have hundreds of thousands of bushels in contract to be planted and harvested.  Peas for processing are being rapidly harvested and replanted, some seed is short.  Sweet potatoes are starting to swell and size.  Processing peppers are being harvested but we have a shortage of labor and multi-millions of lbs. left to harvest.  Processing tomatoes will be finished harvest this coming week.  Spring planted fresh market butterbeans and peas are mostly harvested but seed is short to plant the fall crop. Still have some flooded fields and drowned crop.”

Upstate

Kerrie Roach reports, “Spotty rain across the county again last week has led to continued issues for growers without irrigation. Fall planting for vegetables is in full force. Peaches are looking good, and apples are coming along. Most growers will be putting on a fungicide cover spray this week before significant rains are forecasted.”

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Reverted apple rootstock (believed to be M7) volunteer tree with aborted fruitlet. Photo from Kerrie Roach.

Andy Rollins reports, “Bacterial speck and bacterial spot of tomato are major problems in plum tomato varieties in the upstate right now.  They were not able to control this disease even with a vigorous spray program using mancozeb + copper on several farms.  In nearby plantings of large fruit varieties, the disease is present but not a problem.  Samples have been sent to researchers at Auburn University where the have confirmed the presence of copper resistant isolates from other farms.  Call on your extension agent for assistance with identifying and controlling this problem.”

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Bacterial speck on a tomato leaf from the upstate. Photo from Andy Rollins.

Field Update – 5/18/20

Statewide

Dr. Tony Keinath reports, “With the cooler-than-normal spring weather, two cool-season pathogens also may be active longer than normal. Downy mildew on brassicas, especially kale and collard, mainly affects the lower leaves. Sometimes it will move up onto the larger leaves in the middle of the plant. With a hand lens, you can see white mildew growth in lesions on the bottom of the leaves. In my spring 2020 trial, Presidio, potassium phosphite, and Zampro rotated with potassium phosphite worked well. Organic growers can use Badge X2 copper, which also performed well.

Fusarium oxysporum f. sp. niveum, the soilborne fungus that attacks watermelon, infects roots when soil temperatures are below 82F. At Coastal REC, I am still seeing new plants showing wilt symptoms. Remember that all control measures, and I want to stress all of them, must be applied before or at transplanting. There is nothing that can be done at this stage of crop growth. It is too late to apply fungicides, which will be a waste of money.”

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Tiny dark flecks of downy mildew on the bottom of ‘Blue Dwarf’ kale. Photo from Dr. Tony Keinath.

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Sporulation of downy mildew on the underside of ‘Tiger’ collard. Photo from Dr. Tony Keinath.

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Wilting and yellowing of lower leaves due to Fusarium wilt on watermelon 6 weeks after transplanting. Photo from Dr. Tony Keinath.

Coastal

Zack Snipes reports, “Things are coming along in the Lowcountry.  It has been very windy and I’ve had several farmers tell me that crops are using more water now because of the wind than if it were hot and humid.  Squash, zucchini, cukes, potatoes, and greens are coming off in good volume right now. Tomatoes are just a few weeks away and are in the sizing up stages right now. I have not seen any major pests or diseases as of late.  The conditions are ripe for the development of Powdery Mildew so be on the lookout when scouting watermelon, squash, brassica, and tomato.”

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Tomatoes are looking good and are just a few short weeks away. Photo from Zack Snipes.

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Powdery mildew on the shaded side of a collard leaf. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “It’s dry in the midlands. It’s been great because we haven’t seen much disease lately (especially on strawberries), but we need some rain. The forecast looks like we may get some this week. Strawberries are still yielding fairly well, though we’re starting to see fewer blooms. Fruit size is getting smaller, but taste has still been great. The first few plantings of sweet corn are tasseling now. Brassicas are still growing well, though there is some black rot out there.  Tomatoes, peppers, and cucurbits have been growing fast the last few days also.”

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The earliest plantings of sweet corn are tasseling. Photo from Justin Ballew.

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Black rot symptoms on the margins of cabbage leaves. Photo from Justin Ballew.

Sarah Scott reports, “Peach season is here! Picking several early varieties now and running packing lines. The crop looks good for this season. Bacteriosis started to show up on leaves and fruit in fields. Still picking strawberries. Summer crops like bell pepper and squash are progressing nicely.”

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Phomopsis or twig blight in a peach orchard. Lesions on twigs cause dieback, gumosis and curling at tips. Remove damaged wood and burn. Photo from Sarah Scott.

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Twig dieback from Phomopsis twig blight. Photo from Sarah Scott.

Lalo Toledo reports, “Cool temperatures have slowed down the growth of many vegetables, but most vegetable plants are looking great. Please be aware of possible diseases coming in this week. Wet and hot conditions will be conducive for pests and diseases. Please spray accordingly and scout every two days, if possible.”

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Grasshopper damage on eggplant. Photo from Lalo Toledo.

Pee Dee

Tony Melton reports, “Hail has destroyed at least 10 A squash, 200 A peaches, 30 A strawberries, 8 A blackberries, many acres of field corn, tobacco, rye, and wheat.  Damaged another 35 A strawberries, 300 A peaches.  Thank goodness that the wind has let up for a while and temperatures have risen on tomatoes, peppers, peas, beans, and sweet potatoes.  Thrips have been awful and imidacloprid is only partially controlling them. If labeled use dimethoate, acephate, etc.   More herbicide damage than usual this year because of cool temperatures and wind, even on labeled crops and drift to non-labeled crops has been awful.”

Upstate

Kerrie Roach reports, “With a week of good growing conditions, things are looking great in the Upstate for fruit & vegetable producers. In higher elevations, there were some losses of young tender plants during isolated frost events early last week. With rains expected most of this coming week, things should start to really push for our market vegetable growers. Peaches and apples are on track for a good season.