Field Update: 6/22/20

Coastal

Zack Snipes reports, “A week of unseasonably mild temperatures and damp conditions slowed things down a bit. The warmer weather this past weekend and this week should put things in gear again. Starting to find some armyworms on smaller farms particularly the southern armyworm. Tomato spotted wilt virus has been showing up on tomato fruit in the Lowcountry. The disease is vectored by thrips. Early and mid-season symptoms include stunted plants that will never make fruit and brown/purple mottling on the leaves. Some plants are asymptomatic, meaning that they show no symptoms of the disease. I have been finding plants that are asymptomatic until they fruit and then symptoms appear on the fruit. Using tomato varieties that are resistant to the disease is the best management technique. The Crop Handbook has a list of varieties that have resistance. Using silver reflective mulch will also help with disease management as the mulch will repel thrips which vector the disease.”

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Characteristic symptoms of Tomato Spotted Wilt Virus on tomato fruit. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Last week was very cool and cloudy. Though there was a decent chance of rain most days, we got very little and it remains dry in the midlands. The cool, cloudy weather really slowed things down and growers weren’t able to harvest crops as often as usual. Since there was little sunlight to dry up the dew each morning, powdery mildew really started showing up in cucurbits. It warmed back up over the weekend and plants seem to be growing faster already. Downy mildew still has not shown up here. Keep scouting and applying protective fungicides.”

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Powdery mildew growing on acorn squash foliage. Photo from Justin Ballew.

Lalo Toledo reports, “Squash bugs are active and laying eggs. Please scout for eggs on the underside of leaves and spray as soon as signs are visible. Squash bug nymphs, are gray and have black legs. Refer to the vegetable handbook for proper chemical control. Downy Mildew has been diagnosed in Orangeburg County. Please refer to the vegetable handbook regarding fungicide applications. It’s recommended to stay on a fungicide schedule and to apply protectants even before we start seeing symptoms.”

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Squash bug eggs laid on the underside of a squash leaf. Photo from Lalo Toledo.

Pee Dee

Tony Melton reports, “Cool temperatures making everything late especially peas and okra. Most sweet potatoes are planted. Things are drying out quickly with the heat.”

Field Update – 5/26/20

Statewide

Dr. Tony Keinath reports, “Powdery mildew was found late last week on watermelon at the Coastal REC, Charleston. All watermelon growers should look at the photo below to be sure they can identify powdery mildew in the early stages. The spots are pale yellow, and, unlike squash, may not have white powdery growth under the spot on the bottom of the leaf. See Powdery Mildew on Watermelon Land-Grant Press 1019 for spray recommendations (https://lgpress.clemson.edu/publication/powdery-mildew-on-watermelon/).”

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Light yellow spots on watermelon leaf from powdery mildew. Photo from Dr. Tony Keinath.

Coastal

Zack Snipes reports, “I saw a good bit of powdery mildew last week on all cucurbit crops. I have had several questions this spring about injury to watermelon. I think the strong winds, sand, and spraying damaged the crowns of melons. They are growing out of it now but have had some folks concerned. Bacterial wilt is showing up in tomato as temperatures climb and fruit is loading up in the crop. Keep up with scouting for insects and diseases. Overall things look great.”

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Crown injury on watermelon due to high winds and sandblasting. Photo from Zack Snipes.

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Conditions have been perfect for the development of powdery mildew on cucurbit crops. Photo from Zack Snipes.

Rob Last reports, “Watermelons generally look very good with great color and potential with early fruit set occurring.  Fusarium wilt is active at low levels in some places, as to be expected in areas of impaired drainage.  Also, I observed a little hail damage to watermelons and cantaloupe in Bamberg County.

Midlands

Justin Ballew reports, “It’s been raining a lot in the Midlands, but we really needed some rain. I’ve had almost 6.5 inches at my house since last Monday (5/18). This has slowed down strawberry picking and we have a ton of water damaged berries. Botrytis is loving all the moisture. Most fields look like they will keep producing for a few more weeks,  just stay on top of fungicide programs. The moisture and warm temperatures have most other crops growing rapidly and looking good. Keep an eye out for disease.

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These strawberries sitting in water will be damaged and need to be removed from the field before botrytis begins to develop. Photo from Justin Ballew

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Tomatoes are loving the warm weather. Photo from Justin Ballew.

Pee Dee

Tony Melton reports, “Anyone have an ark?  Many fields are flooded. Nutrients are washing away and strawberries are water-soaked.  Some strawberry farmers have stopped picking.  Water-logged soil causing crops to stop growing and we have to rely on airplanes to spray crops.  Weeds are enjoying the rain.”

Bruce McLean reports, “Last week was rainy in most locations, and this week looks like more of the same. Disease pressure is elevated due to excessive moisture. Seeing gummy stem blight showing up in cucumbers and bacterial spot in tomatoes. Thrips pressure had been high going into last week (especially on beans, peas, and cucumbers), and could still be high in the few locations that missed the heavy rains. But everywhere else, the heavy rains likely reduced thrips activity. Strawberries are finishing up. Heavy rains damaged most of the remaining red fruit. Blueberry harvest is starting to increase. Prior to rains, fruit was looking really good. The excess moisture did cause some fruit splitting, but no long term damage to the crop. Haven’t seen much thrips activity in muscadines yet, but now concerned with increased problems with calyptra release, a condition known as stuck cap. It’s a little early to tell, but could reduce yields.

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Thrips damage to southern peas. Photo from Bruce McLean.

Upstate

Kerrie Roach reports, “We are building the ark to send down to Tony in the Pee Dee!  Lots of flooded fields last week (and today) with many places seeing 4-6 inches of rain over 3 days. Strawberry growers halted picking and worked around the rains. Vegetable producers are replanting washed out crops and draining fields.  Peaches and apples continue to be on track for a good season. Localized hail damage is showing up on apples in Mountain Rest from one of the storms a few weeks ago.”

Field Update – 6/3/19

Statewide

Dr. Tony Keinath reports,”Powdery mildew was found on watermelon at the Coastal REC on May 30. Typical symptoms of powdery mildew on watermelon are distinct yellow spots, although the spots may be indistinct yellow blotches rather than round spots. The symptoms seen this week included more browning than is typical for the size of the spots, perhaps due to unusually hot weather.  To manage powdery mildew on watermelon and other cucurbits, click here. Powdery mildew-resistant cultivars of cucumber and cantaloupe are holding up well, but squashes with partial resistance to powdery mildew should be sprayed.”

Yellow spots include more browning than usual for powdery mildew. The hot weather probably contributed to this. Photo from Dr. Tony Keinath.

Coastal Region

Zack Snipes reports, “Another week without rain for most of the Lowcountry.  The irrigated crops that have gotten enough water and look great including tomato, watermelon, cantaloupe, cucumbers, and squash. We are at the beginning of tomato, melon, rabbiteye blueberry, and blackberry harvest.  Blueberry growers will want to look out for anthracnose fruit rot in harvested berries.  There is nothing that can be done this year but we can work on spray programs for next year.  The tomato crop looks great except for the usual bacterial wilt and southern blight.  I heard of a few hot spots of spider mites last week so scout regularly especially during this hot and dry period.”

Cantaloupe looking good in the Coastal region. Photo from Zack Snipes.

Anthracnose in blueberries. The photo on the right shows berries that were just picked. The berries on the left were picked 3 days prior to the photo being taken and stored at room temperature. You can see the orange spore masses on some of the berries. Photos from Zack Snipes.

Midlands

Justin Ballew reports,”Last week was another hot, dry week. It’s been 23 days now since we’ve had rain that amounted to anything more than a brief sprinkle. Irrigation systems are not getting much rest. Squash and zucchini yields have suffered some, most likely because bee activity decreases when it is extremely hot and dry. We have some blueberries that are suffering because the drip system is not able to keep up with the water demand. Other irrigated crops like sweet corn, tomatoes, peppers, and eggplant are looking fine. We need rain pretty badly, though.

Collards just outside of the reach of the end gun are wilting and the bottom leaves are drying out. Photo from Justin Ballew
Blueberries are showing signs of drought stress in the Midlands. Photo from Justin Ballew

Sarah Scott reports, “Things are busy and man has it been HOT! I’ve been speaking with Brett Blauuw, entomologist from UGA,  about what to expect when the temps dip back down to “normal” as far as the pest outlook is concerned and here are some notes from our conversation:

  • Scale insects tend to become inactive at temperatures greater than 90, but they will continue to develop at night when the temperatures dip back down. The activity should decrease compared to a ’normal’ spring where it’s in the 80s. We still have a couple of weeks before we see another peak abundance of scale crawlers.
  • Stink bugs don’t mind the heat much. The adults that emerged from overwintering are dying right now, so the numbers are declining but, they have laid eggs and the nymphs will be developing. In a couple of weeks we should expect another large number of BMSB adults. 
  • Plum curculio is also more abundant and active this year. Still catching adults down in Fort Valley, so that is another concern.
  • Thrips, unfortunately love hot, dry climates, so right now is the perfect weather for them. For organic producers, Entrust is an affective product.”
Squash bugs showing up on cucurbits in the Midlands. Photo from Sarah Scott.

Field Update – 5/20/19

Statewide: Dr. Guido Schnabel reports, “Green fruit rot is starting to show up in commercial peach orchards. This disease is caused by the fungus Monilinia fructicola. In spring we had an extended period of bloom with lots of rain. That led to blossom blight caused by the same fungal pathogen. Growers must take this disease very seriously as it can cause significant preharvest and postharvest fruit rot. Many take advantage of our lab service to determine potential weaknesses in fungicide spray programs. For more information contact your local county agent or Dr. Schnabel directly at schnabe@clemson.edu.”

Green fruit(Monolinia fructicola) rot on a peach. Photo from Dr. Guido Schnabel.

Coast: Zack Snipes reports, “We have had nice warm weather that is helping the development of irrigated crops.  We are starting to get dry and could use some rain for dry land crops and to settle dust. We are in the middle of squash and cucumber harvest.  We are starting to see powdery mildew show up on cucurbit crops. The tomato crop looks promising this year despite the usual bacterial wilt common in fields.  To test for bacterial wilt, select a wilting plant, cut it through the stem, and put into a jar of water.  If the pathogen responsible for bacterial wilt is present (Ralstonia solanacearum), you will get what’s known as bacterial streaming which is a milky white stream coming from the cut end of the plant.

Bacterial wilt ( Ralstonia solanacearum) on tomato. Photo from Zack Snipes
Powdery mildew on squash leaf. Photo from Zack Snipes.

Midlands: Justin Ballew reports, “The weather this past week was pretty mild, but dry. Thrips have become a problem in strawberries in some areas, but we are so close to the end of picking that most growers would not benefit from a treatment. Production has really decreased and some growers have already begun redirecting picking labor to other crops. Spring planted squash and peppers are starting to come into production and everything is looking pretty good. Keep an eye out for spider mites on tomatoes as it gets hot and stays dry this week.

Thrips damage on developing strawberry.
Peppers are developing well in the midlands. Photo from Justin Ballew

Sarah Scott reports, “We have begun picking early varieties of peaches across the Ridge. Things are looking good for a nice crop this year. Green fruit rot (Monilinia fructicola), also known as brown rot, has shown up in a few spots around the Ridge. We are continuing to monitor stink bug populations in orchards. Traps have shown high numbers of insects but damage has been scattered in this area.

Peaches are looking great on the Ridge. Photo from Sarah Scott.
Stink bug trap on the edge of a peach orchard. Photo from Sarah Scott.

Field Update – 4/29/19

Statewide: Dr. Tony Keinath reports finding powdery mildew on Hale’s Best Jumbo cantaloupe in Charleston last week. “Anyone growing heirloom varieties of cucurbits should spray for powdery mildew, because open-pollinated varieties do not have the resistance found in hybrid varieties. All cucurbit growers should be on the lookout for powdery mildew starting now and be ready to spray when it shows up on their farms.”

Dr. Guido Schnabel reports, “2019 promises to be a great peach season despite the one late freeze we had late March. Still, some remnants of this late freeze can still be observed on many cultivars. They include peach buttons next to well developing fruit. The embryo of those button peaches are often damaged. These buttons will soon fall off the tree. Most cultivars do have enough normal fruit, however, for a full or nearly full crop.”

Freeze damaged peaches and healthy peaches. Photo from Dr. Guido Schnabel.
Peach button with dead embryo due to freeze damage. Photo from Guido Schnabel.

Coastal: Zack Snipes reports, “Beautiful weather last week really helped the progress of spring crops like tomato, pepper, and squash. We should be harvesting the first flush of squash this week. Spring onions, broccoli, radishes, carrots, beets, turnips, and greens are continuing to be harvested. Have seen some major issues with the diamond back moth this spring on greens.”

Tomatoes are growing well in the Coastal Region. Photo from Zack Snipes.
The first squash harvest is getting close in Charleston. Photo from Zack Snipes.

Midlands: Justin Ballew reports, “Strawberry harvest has picked up this week and disease is very low since the weather has been dry. Spring and Summer crops are growing fast. A few spidermites have been seen and could increase quickly if it stays dry. Keep an eye out for those.”

Sarah Scott reports finding high numbers of brown marmorated stink bugs in traps along the Ridge. “While scouting the orchards I saw a few peaches that had some stink bug damage as well. Not wide spread but it is showing up so be mindful when you’re scouting in the coming week.”

Stink bug damage on a young peach. Photo from Sarah Scott.

Upstate: Andy Rollins reports, “Strawberry production is finally in full swing after a very delayed start to our year.  Early picking resulted in some knotty fruit but fruit quality and flavor are excellent now across all of the upstate. Slug problems show up when we have high moisture conditions as in the below picture from a neighboring state. Deadline pellets are a very effective control should they show up here, but caution is needed to keep the pellets from directly contacting fruit when applying.”

Strawberry harvest is in full swing in the upstate.
Slug damage on a strawberry. Photo from Andy Rollins.