Weekly Field Update – 6/1/21

Posted on June 1, 2021 by Justin Ballew

Coastal

Rob Last reports, “On the whole disease pressure in most crops remains low. The exception is cucurbits where we are finding powdery mildew in cucumbers as well as downy mildew. Cucurbit bacterial wilt has been found in isolated fields. This disease is characterized by wilting of one vine or the whole plant. Once cut the stem will ooze a sticky sap from the wound. It is transmitted by the feeding activities of cucumber beetles. Strawberries are beginning to slow down while tomatoes peppers and peaches are doing very well.”

Midlands

Justin Ballew reports, “We had an unseasonably hot week last week followed by a much cooler weekend. Some places received a little rain early in the week and some places received a little on Saturday. However, the Midlands are very dry overall. Crops responded well to the heat last week. Brassicas and cucurbit crops progressed extremely quickly. Squash and zucchini are setting fruit and some are being picked. Brassica and herbs are still being harvested. Tomatoes are setting fruit, but we still have a little time before picking on a large scale.”

A bumble bee pollinating a squash blossom. Photo from Justin Ballew.

Sarah Scott reports, “Peaches are still going strong in the Ridge. Some varieties are showing more cold damage than anticipated, but there is still a good crop out there. It seems that the very early varieties and then some of the very late varieties are the ones with the most damage. Some bacterial spot is showing up but not near as bad as last season, mainly due to dry conditions. We’ve had some really hot days but this past week we finally got some relief from the temperatures and some cloudy days. Hopefully rain is in the future as growers are irrigating heavily now. Some second croppings of Camarosa strawberries are still being harvested this week. Squash, zucchini, and cucumbers are producing well. Insect pressure is starting to occur more heavily, but disease, for the most part, is still at bay.”

Pee Dee

Bruce McLean reports, “Blueberry harvest, after getting a late start, is starting to provide good quantities. Strawberry harvest is winding down for most. Last week’s heat caused much of the strawberries to become soft and unmarketable. Some varieties are still holding up though, with limited harvest. Some early blackberries are being harvested in good volume, with very good quality. Peach harvest is light and fruit is a bit small. Tomato harvest should begin late this week/early next week. Tomatoes have been experiencing some environmental stress (heat, low humidity, high UV), causing some leaf curl. This should subside with the increased moisture and lower temperatures. Squash are starting to be harvested. Cucumbers harvest isn’t far away. Peas and beans have been affected by thrips, but are growing out of that damage. Sweet corn harvest is getting near. Vegetable planting is starting to resume with the recent moisture and reduced temps.”

Although small and difficult to see, thrips (larva pictured above) can be a limiting factor for yield in muscadines. Thrips feed upon the blooms of the crop, damaging the flowers and early developing fruits. Checking for their presence during bloom is critical for their control. Placing a sheet of white paper underneath the clusters of blooms and forcefully bumping the wire or cordon with your fist should dislodge the insect, allowing it to drop onto the paper for detection. The size of the insect is small – about 0.5 – 1.0 mm in length.

Tony Melton reports, “Peppers and tomatoes are setting fruit. Harvesting pickles consistently. Applying downy mildew and pickleworm materials regularly. Finishing up first cut of collards for processing. Started 2^nd cut of processing turnips. Harvesting processing cabbage. Snap beans and butter beans are flowering. Setting sweet potatoes as fast as slips become available.”

Weekly Field Update – 5/17/21

Posted on May 17, 2021 by Justin Ballew

Check out the new podcast, “The SC Grower Exchange” featuring Clemson Extension fruit and vegetable agents. The podcast is moderated by Sarah Scott from Edgefield and covers a more detailed look at what is happening in the fields across the state. New episodes are recorded weekly, so listen weekly and subscribe through Spotify, Google, or Apple.

Coastal

Zack Snipes reports, “Everything is progressing nicely in the Lowcountry. We got some much needed rain last week. Temperatures have been cool so things are somewhat slow from a developmental standpoint. All the crops look great especially the tomato crop. We have a really nice fruit set and very little disease. I am expecting to see bacterial spot to show up sometime soon and have been getting a few calls about bacterial wilt taking down plants. I’ve also gotten a few calls about blossom end rot. That is typical on the first fruit set and will usually correct itself provided there is ample calcium in the soil AND the soil moisture is consistent. In our sandy soils the main cause of blossom end rot is allowing the soil to dry out during the fruiting stage. Folks might want to consider multiple 30 minute to 1 hour irrigation cycles on tomatoes per day.”

A beautiful field of tomatoes on one of the Sea Islands. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We got right at an inch of rain at my house this past Wednesday. While the rain was much needed, the moisture and cool temperatures has allowed plant diseases to get a foothold in numerous crops. Over the last week, I’ve seen bacterial blight in mustard, downy mildew in collards, Septoria leaf spot in Italian parsley, and of course botrytis and a little bit of anthracnose fruit rot in strawberries. Growers have been sanitizing, applying fungicides, and/or terminating old crops to manage disease. When selecting fungicides, be sure to rotate MOA groups (referred to as “FRAC Codes” in the SE Vegetable Crop Handbook) to avoid developing fungicide resistance in your fields.”

Bacterial blight showed up in mustard following the recent heavy rain. Photo from Justin Ballew.

Pee Dee

Tony Melton reports, “A major pickle company found cucurbit downy mildew on pickles in Calhoun County. I have seen 100 acres of pickles damaged by hail and another 100 acres damaged by Reflex carry over. Next year, please make sure you are planting the right variety of strawberry for the intended market. When markets get full like this year, buyers are picky of the variety they will buy and many acres were not harvested to their full potential. Remember to control thrips on small peas, cucumbers, and beans. Also, control thrips in the flowers of tomatoes and beans.

Weekly Field Update – 4/5/21

Posted on April 5, 2021 by Justin Ballew

Coastal

Zack Snipes reports, “Temperatures checked in at 28 F at the northern end of Charleston County one night this past week. Strawberries were covered but some blossoms are showing damage. The weather this week should really push berries and give us our first big flush of the season. Lots of acres of tomatoes are planted and before the cold were looking pretty good. Time will tell how much the cold will slow them down. It has been very windy in the Lowcountry as well which I think has slowed down development on some crops. Spring brassicas are looking great with very low worm pressure right now. That does not mean we should stop scouting. Populations can jump very quickly.”

Tomatoes were looking ok before the cold nights. Photo from Zack Snipes.

A fall seeded brassica crop beside strawberries is blooming. The thought behind this cover crop is the early blooms will encourage beneficial insects that will prey on the early season thrips which have been causing lots of cosmetic damage on strawberries the past few years. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We had a couple frosts late last week and the temperature got down to 30 degrees at my house. Growers covered their strawberry fields, so we don’t expect to see any damage there. We’re getting very close to picking on a larger scale. I’ve seen some nutrient deficiencies in a few strawberry fields, so be sure to tissue sample periodically and adjust fertigation accordingly. Now that we’re into April and the forecast looks warm, many growers will begin planting cucurbit crops this week. A few already had seed in the ground before the frost. The first plantings of sweet corn are up and growing well.”

One of the first plantings of sweet corn is up and looking good. Photo from Justin Ballew.

Pee Dee

Tony Melton reports, “Still determining damage from frost. One grower had 40 A of butterbeans emerging – sprayed with a frost control product. Sweet potatoes slips are up, covered with plastic, and beds are covered with slips (about a month out from planting). Cabbage is beginning to cup, head, and touch in the rows. Asparagus was hurt by cold and most harvest is over. Starting to plant pickles, peppers, and tomatoes. Picked all ripe fruit and sprayed for disease before frost – this coming weekend will be a good harvest for most growers.”

Upstate

Kerrie Roach reports, “With some very cold nights last week in the upstate, the apple and peach crops took a significant hit. With extreme differences in topography, each grower has different severities of loss, but the overall consensus is not great. It will be another week to tell for sure on the apples and a little over a week to tell on the peach crop with certainty. One orchard recorded a low of 25 degrees F on the first night and 26 the following night. Night one was actually less damaging because of a persistent wind, where night two was calm and allowed the cold air to settle in. As we assess damages in the orchards, here is a great explanation of how it is done: https://extension.psu.edu/orchard-frost-assessing-fruit-bud-survival

Weekly Field Update – 8/17/20

Posted on August 17, 2020 by Justin Ballew

Statewide

Dr. Tony Keinath with a word on crop rotation. “To keep the soil on your farm productive over the long term, do not replant the same vegetable, or a related crop, in the same field “too often.” How often is “too” often depends on the crop and the pathogens present in the soil. Almost always, “too often” is less than 12 months between disking the old crop and planting the new crop. A general rule of thumb is 24 months between related crops, and in some cases, 36 months (3 years) is needed.

The main risk in replanting “too often” is building up root pathogens that survive in soil for years. Even in the heat, diseased roots and stems take several months to decay enough so they are not a source of pathogens. Thicker tissue, like the crowns of cantaloupe, can take 2 years to decay.

Another risk is foliar diseases that start on volunteers from the previous crop. The pathogens may be in or on some of the seed that sprouts, for example black rot on leafy brassica greens or gummy stem blight on cantaloupe and watermelon. A small number of infected volunteers means the disease has a head start right at the beginning of the crop.

Controls for soilborne pathogens (fungi, water molds, and nematodes) are limited.

Many vegetable crops have no resistance to these pathogens.
Fungicides do not penetrate soil well, or they are quickly inactivated.
Fumigants have many restrictions that require time-consuming record keeping and air monitoring.

Root-knot nematodes are a special problem, because they form galls on many vegetables and some field crops (cotton, for example) grown in rotation with vegetables. Summer cover crops of sunn hemp can lower nematode numbers. See https://edis.ifas.ufl.edu/in892 for a list of other warm season cover crops that help manage nematodes.

Without crop rotation, more fungicide sprays will be needed, which raises the risk of fungicide resistance. Fungicides and fumigants are not a substitute for good crop rotation.”

Midlands

Justin Ballew reports, “Many areas got a little more rain last week and we had a break from the heat over the weekend. We have a lot of the fall crop planted now including squash, zucchini, tomatoes, and brassicas. So far everything is mostly growing well. We are seeing bacterial wilt develop in some of the fall-planted tomato fields. Bacterial wilt loves hot soil temperatures, which is typical this time of year. Be sure to follow a proper crop rotation plan (at least 3 years) to help manage bacterial wilt buildup in fields. Since the heavy rain we got a few weeks ago, we’ve also seen plenty of bacterial spot in what’s left of the spring tomatoes.”

To test for bacterial wilt in tomatoes, place the cut stem in a jar of clean water. If the plant is infected, within about 30 seconds you will see milky, white bacterial ooze begin to stream from the stem. Photo from Justin Ballew.

Bacterial wilt commonly causes discoloration of the tissue within the stem. Photo from Justin Ballew.

Pee Dee

Bruce McLean reports, “Most summer vegetable crops are starting to wind down. Peas, okra, watermelon, cantaloupe still harvesting at some volume. Late summer/fall squash, cucumbers and tomato harvest are a couple weeks away. Fresh market muscadines are being harvested now. Juice and wine muscadines are getting close – maybe 7-14 days away, depending upon location. In most juice and wine muscadine vineyards, Carlos is around 40% colored (ripe), Noble is around 60%, and Doreen is around 25%. Grape root borer (GRB) flight is still occurring, with moderately high moth counts in traps.”

‘Noble’ muscadines getting close to harvest. Photo from Bruce McLean.

Tony Melton reports, “‘Another Crop Bites the Dust’ from spreader/stickers. I have seen too many farmers sing this sad song. Be careful and know what you are doing when adding a sticker/spreader when spraying vegetables. Short season, tender vegetable crops will burn very easy in our heat and do not have time to come back like long season row-crops. Our state’s second major watermelon/cantaloupe season is in full season in Chesterfield County. Harvest is in full swing and will continue until frost. Curculio sprays are beginning to be applied to the fall pea crop. Looks like pickle harvest will continue until frost.”

Field Update – 7/20/20

Posted on July 20, 2020 by Justin Ballew

Statewide

Dr. Matt Cutulle reports, “It is always good to control goosegrass even if it is past the critical period for competition with the crop. Lack of late-season control made hand-harvesting tomatoes difficult in the field pictured below. Also, there will be a huge deposit of goosegrass seeds into the soil seed bank for next year unless the seeds are destroyed after the harvest.”

Late season goosegrass growth can make harvest difficult and contribute lots of seed to the seed bank, which will have to be dealt with in future crops. Photo from Dr. Matt Cutulle.

Coastal

Zack Snipes reports, “We experienced a nice hot week of weather in the Lowcountry. Most crops are finishing up with the heat and recent rains. On later season tomato I have seen bacterial leaf spot on the fruit which makes fruit unmarketable. I am seeing this on the second cluster of fruit set and not on the first or third clusters. Hemp seems to be off to the races and looking pretty good so far. There are within every hemp field occasional wilted, stunted, and yellowed plants. These plants always have a weak root system and most of the time have girdling and interveinal discoloration. Peppers and eggplants are loving this heat and are producing in high volumes.”

Bacterial leaf spot showing up on the second set of fruit on the tomato plant. Photo from Zack Snipes.

Wilting of hemp is very common and often sporadic throughout fields. Photo from Zack Snipes

Midlands

Justin Ballew reports, “Last week was hot and mostly dry, though we did have some scattered thunderstorms come through over the weekend. Field prep for fall crops continues. We’ve had some fall tomatoes, peppers, and brassicas transplanted already and more to come this week. Everything is growing pretty fast right now and we’re still picking spring crops. Keep an eye out for spider mites, as they love the hot, dry weather we’ve had lately.”

Fall tomatoes transplanted in Lexington this past week. Photo from Justin Ballew

Sarah Scott reports, “We are still ahead of schedule on peach varieties being harvested. Early August Prince and August Prince are being picked now which is over a week earlier than usual. The fruit quality is still good with slightly smaller than ideal fruit. With the extreme heat and lack of rain in the past week, summer crops like tomatoes and cucumbers are looking rough. Bell peppers are doing well.”

An Edgefield County grower assessing his Early August Prince orchard. Photo from Sarah Scott.

Pee Dee

Bruce McLean reports, “Sweet potatoes are looking good. Establishment seems to be very good for the most part. Long green cucumbers, yellow squash, zucchini, cantaloupe, peas, okra, and sweet corn are harvesting well. Condition is good to very good. Sweet corn will be wrapping up shortly. Blueberries are pretty much finished, with only a few remaining fruit on Powderblue. Fruit condtion is fair to good. Muscadines are coming along nicely and appear to have an excellent crop. Fresh muscadines should be beginning harvest soon, with wine/juice grapes still a few weeks from harvest. Be on the lookout for Grape root borer moths. They are starting to emerge. They were being caught in traps placed in vineyards in Marion and Horry counties.

Grape root borer moths being caught in a bucket-style trap. Photo from Bruce McLean.

No, this is not a paper wasp. It is a grape root borer moth. Photo from Bruce McLean.

Tony Melton reports, “Harvested first crop of processing peppers. Continuing to pick and plant pickles. Processing greens are over for the spring crop. Harvesting the first crop of processing and seed peas and planting fall crop. Getting processing tomatoes out of the field as quickly as the plant can take them. Things are drying out, hope we don’t go into drought with the heat.”

Upstate

Kerrie Roach reports, “Spotty rain and high temperatures have left many small growers scrambling for irrigation options throughout the Upstate. Peaches and nectarines are still being harvested. Blueberries are just about finished, and farmers’ market produce is starting to wind down with the heat. Apples should begin next week with early varieties like ‘Ginger Gold’ and ‘Golden Supreme’.”

Andy Rollins reports, “Plenty of early blight, bacterial spot/speck on tomatoes this season, but some of the more troublesome problems have been various tomato virus problems. When diagnosing virus problems it is important to get lab verification because herbicide injury can look very similar when just going by visual symptoms. If you suspect herbicide drift from a neighboring farm. Look for damage to other broadleaf plants in the area in between the suspected source and the damaged plants. Follow the wind direction. You should have more severe damage on the leading edge. Also, herbicide residual from a previous crop like sunflowers can also give you herbicide damage that you did to yourself. Read and follow all pesticide label directions. There are plant back restrictions on some herbicides so be careful. If this is the case the damage should be fairly consistent/uniform throughout the area that was planted in the other crop.

Unlike both of these other situations, virus problems may come from your seed source, the greenhouse where plants were grown, or from weeds in the field. Pokeweed is commonly a source, as are many other broadleaf weeds. Thrips, aphids, and whiteflies are all known to vector viruses into plants. Symptoms are what you see below with “shoestring” looking leaves, leaves with distorted veins, and mosaic yellow and green coloration. There are many viruses that infect plants. Each of them can show different symptoms and also they can each look different on other plants as well. It’s even possible for a healthy-looking plant with no symptoms to be infected with several viruses.”

“Shoestring” type leaf distortion may be a symptom of a virus or herbicide damage. Get confirmation from the plant disease lab. Photo from Andy Rollins.

Field Update – 7/6/20

Posted on July 6, 2020 by Justin Ballew

Coastal

Zack Snipes reports, “It was a warm week with some sprinkled in showers along the coast. All crops are coming in right now with heavy watermelon volume. What’s left of the tomato crop is ripening fast. As far as pests go, I have seen a good amount of bacterial leaf spot in pepper, squash bugs and cucumber beetles in squash, and spider mites on beans, tomato, and melon.”

Squash bugs and their bronze eggs on a zucchini. Photo from Zack Snipes.

Spider mite activity has increased with the warm weather and a missed spray or two. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We got a little more rain last week and the temperatures were a little warmer than previous weeks. We’re still harvesting tomatoes, sweet corn, peppers, eggplant, peaches, squash, zucchini, beans, etc. Since the environment has been warm and wet, we’re starting to see diseases pick up. Seeing lots of powdery mildew and anthracnose on cucurbits and bacterial spot on tomatoes. Stay on your fungicide programs and rotate modes of action as much as possible. I’ve also been getting some reports of heavy spider mite activity on tomatoes.”

We are seeing lots of bacterial spot show up in tomatoes following the recent rain. Photo from Justin Ballew

Spider mites generally feed on the lower side of tomato leaves and cause a stippling appearance. Photo from Justin Ballew.

Sarah Scott reports, “We’ve had hot and, for the most part, somewhat dry conditions in the past week. Some areas received an inch of rain but it was very spotty. Tomatoes, peppers, squash, corn, cucumbers, and melons are all being harvested now. Plums, peaches, and nectarines are also still being picked. The peach crop is about 10 days ahead of schedule.”

Peaches are looking good and coming in a little early. Photo from Sarah Scott.

Pee Dee

Bruce McLean reports, “Vegetable crops are maturing nicely, even though some are exhibiting heat stress from the recent hot weather. Cucurbit Downy Mildew (on cucumbers) has been reported throughout the Pee Dee Region. Powdery Mildew is widespread on zucchini and yellow squash. Sweet corn is looking good, with good volumes being produced. Tomatoes, other than being stressed from the heat and the humidity, look pretty good and are bearing well. Sweetpotatoes are still being planted. Muscadines are beginning to size and look to be a very good crop. Blueberries are winding down, with only the latest varieties being harvested now.”

Tomato plant showing some stress from the heat and humidity of summer. Photo from Bruce McLean.

Tony Melton reports, “Processing peppers and tomatoes are beginning to be harvested and they look good. With all the early winds and excessive rain, it was difficult but as my daddy would say “we made a silk purse out of a sow’s ear.” Second and third crop pickles are yielding much better than the weather-beaten first crop. Processing peas will begin harvest this next week, so we badly need some dry weather but the forecast is not favorable. Also, the amount of cowpea curculio is increasing rapidly and an intense/timely spray program is needed to prevent what most call “stings (maggots) in the peas.” One grower got slack on his spray program and this week had to discard $6,000 worth of peas. Spray with a pyrethroid at or before the first flower, then every week until flowering is finished. The first spray is the most important because if you wait too late, the curculios are already in the field. Curculios are very hard to kill. When disturbed they ball-up inside their protective coat, and your spray is repelled. My program repels them and attempts to keep them out of the field. Also, rotation is very important to keep down the population of curculios surrounding your fields.”

Upstate

Kerrie Roach reports, “Upstate peaches are beginning to ripen! While exciting, we have seen some physiological issues with sizing and softening that we attribute back to a late-season cold spell. While the peaches originally appeared to pull through without damage, we are now seeing peaches that are not sizing and those that do size up, only ripen on the very outer portion. It is a waiting game to see how each variety ends the season. In the meantime, market vegetable production is in full swing and the apple crop is looking fabulous.”

Some peaches in the upstate are not sizing up properly, probably due to the late cold spells in the spring. Photo from Kerrie Roach.

Field Update – 6/29/20

Posted on June 29, 2020 by Justin Ballew

Coastal

Rob Last reports, “In our area crops are generally looking good with watermelons and cantaloupes coming to harvest. From a pest perspective, we are finding some early pickleworm and melon worm damage occurring. In addition, cucumber beetles and squash bugs remain active. Cucurbit downy mildew is being found in the area and as such protectant fungicide applications remain viable options. If in doubt scout.”

Zack Snipes reports, “Last week was full of heavy rain and heat. It finally feels like June. Crops are either going one of two ways right now: they either look great or they are succumbing to disease. Tomatoes are picking great and I’ve seen some really nice watermelons finish up this week. Peppers are loving this heat but I have seen an uptick in bacterial leaf spot (BLS) in the crop. Keep up with spray programs (copper and Manzate) for BLS in pepper. Tomatoes are also starting to look rough with all the heat and rain. If your tomato crop dies, please identify the culprit so we can better manage it next year. Soilborne diseases such as bacterial wilt and southern blight will not go away next year. I will be more than happy to work with folks on crop planning, cover crops, and rotation on their farms so we can avoid crop failures.

A quick cut of the stem of a wilting plant and a dip into water can help to positively identify Bacterial Wilt in tomato. The presence of the pathogen will yield a clear to white ooze coming from the plant after a few minutes in the water. Photo from Zack Snipes.

Bacterial Leaf Spot is spreading in pepper due to the heavy rains and increased heat. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We finally got some widespread rain mid-week and it has rained in places most days since. Some areas received enough rain to cause temporary flooding in lower-lying fields. Remember, according to produce safety guidelines, any produce that was flooded may not be harvested. We should expect diseases to worsen in the coming weeks. Powdery mildew in cucurbits and bacterial spot in tomatoes has certainly increased in the past week. Crops are still developing very rapidly and we are picking lots of squash, zucchini, cucumbers, tomatoes, eggplant, sweetcorn, greens, beans, etc.”

This field of cucumbers was temporarily flooded by the heavy rain last week. Photo from Justin Ballew

A crew picking squash in Lexington. Squash and zucchini are growing like wildfire in the midlands. Photo from Justin Ballew.

Pee Dee

Tony Melton reports, “Raining almost every day some storms causing downed trees. Root rot bad applying a lot of potassium phosphide. A few strawberry growers still picking around rains. Downy mildew bad but Ranman and Orondis are doing a good job of control. Peas are maturing and will not be too long until harvest. We need to hurry to get the second crop planted on the same land. Still planting sweet potatoes. Okra and tomatoes just started to bare. Southern stem blight is bad and we’re spraying Fontelis. Some first crop butterbeans are being harvested.”

Field Update – 6/8/20 (Downy Mildew Arrives in SC)

Posted on June 8, 2020 by Justin Ballew

Statewide

Downy mildew was found in Charleston, SC late last week on cucumbers. This is the first confirmed report of the 2020 season. If not already doing so, all cucumber and canteloupe growers should begin applying protective fungicides to help prevent or manage downy mildew. Ranman tank-mixed with a protectant such as chlorothalonil, mancozeb, or Zampro is a good option for protecting plants prior to symptom development. For more info, see Dr. Tony Keinath’s CDM Management publication.

Downy mildew symptoms on the top side of a cucumber leaf. Note that the spots are angular in shape and are delineated by the veins in the leaf. Photo from Justin Ballew.

Dark-colored downy mildew spores developing on the underside of a cucumber leaf. Photo from Justin Ballew.

Coastal

Zack Snipes reports, “It is a very busy time out in the fields. Every crop is coming in right now and folks are busting it to get crops out and keep the remaining crops healthy. Keeping up with fertility, fungicide, insecticide, and herbicide programs can really help with the bottom line as now is when our crops need a little help. With the mild temperatures and cloudy, wet days last week, I saw some diseases appear and spread. On tomato, I am finding increased bacterial spot that is starting to make plants turn yellow. This will cause a yield drag and the spots can be found on the fruit if the infection is not slowed down. Downy mildew was found in cucumber last week so be sure to be proactive and keep an eye out for that. I saw some other cucurbit diseases last week including gummy stem blight and Alternaria. The stink bug population has also increased in the past week or so with some damage showing up on tomato. Please refer to the 2020 Southeastern Crop Handbook for details on management programs for insects, diseases, and weeds.”

Bacterial spot is increasing causing yellowing of the plants. Bacterial spot can reduce yields and develop spots on the fruit. Photo from Zack Snipes.

Downy mildew found in cucumbers last week. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Last week was warmer and actually a little dry. Lots of irrigation has been running. Crops are progressing quickly. Strawberries are mostly done now. The silks on the earliest planted sweetcorn are browning and harvest isn’t far off. Tomatoes, peppers, eggplant, squash, beans, and cucumbers are also progressing well. Downy mildew has been found in the state, so be sure to start preventative fungicide sprays on cucumbers. Let us know if you’d like help scouting fields for downy. Collards, cabbage, and kale are still being harvested and are looking good.”

Silks are turning brown on the earliest sweet corn plantings. Photo from Justin Ballew.

Tomatoes are developing well. It won’t be long before harvest starts. Photo from Justin Ballew.

Lalo Toledo reports, “Downy Mildew has been diagnosed in Charleston County. However, Downy Mildew has not been found in Orangeburg county. Please be advised that it is a matter of time before we start seeing symptoms. 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. Bacterial Wilt on tomatoes is present in many fields in Orangeburg county. Please contact your local extension office for proper recommendations.”

It’s only a matter of time before downy mildew shows up in cucurbits in Orangeburg County. Photo form Lalo Toledo.

Pee Dee

Bruce McLean reports, “Field conditions really improved this past week. Cucumbers are being harvested in good volumes. Overall, quality is good. Downy mildew is starting to show up in cucumber fields that were affected by recent heavy rains. Squash and zucchini are beginning to be harvested, as well. Snap beans and southern peas are flowering heavily. Some acreage of snap beans were lost due to ponding caused by recent heavy rains. Many fields of sweet corn are tasseling well and beginning to silk. Watermelon, cantaloupe, and peppers are growing very well. Blueberry quality is beginning to improve. Much of the rain-damaged fruit has been removed. Currently, the blueberry crop looks good. Muscadine fruit set is good, but thrips and aphid activity is high, which could cause problems in yield. Scouting is necessary to determine pest presence and necessary insecticide application.”

Downy mildew really showing up in rain-stressed fields. Photo from Bruce McLean.

Snap beans affected by ponded water from recent heavy rains. Photo from Bruce McLean.

Tony Melton reports, “Some areas got 10 inches of rain in one day. Hundreds of acres of beans and cucumbers are drowned. Cucurbit downy mildew is here on cucumbers. Weeds are awful.”

Upstate

Kerrie Roach reports, “With heavy rains a few weeks ago, high humidity and heat this past week, we are seeing some disease problems pop up across the board… make sure you are following prevention practices that fit into your growing style. Conventional, organic, or somewhere in between, all growers should be managing disease through preventative measures. Crop rotation is arguably one of the most important strategies in an Integrated Pest Management (IPM) program. If you’re a grower that hasn’t moved crops around within your site in years, now is that time!”

Andy Rollins reports finding black knot of plum. “Prune out these galled up branches as quickly as possible before they begin to sporulate. I also recommend sterilizing or at least sanitizing the pruners as much as is possible between cuts. Treat with 2 lbs of Captan foliarly as soon as possible after pruning to try and keep those wounds free from other problems. This problem can come in on the purchased trees, but can also come in from wild cherry trees or wild plum surrounding the orchard. It is always a good thing to kill any and all wild cherry and plum trees directly adjacent to a commercial orchard. Penn State has some good information here.”

Black knot on plum branches should be pruned out before sporulation begins. Photo from Andy Rollins.

Field Update – 5/26/20

Posted on May 26, 2020 by Justin Ballew

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/).”

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.”

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

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.

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

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.

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 – 5/18/20

Posted on May 18, 2020 by Justin Ballew

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.”

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

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

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.”

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

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.”

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

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.”

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.

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.”

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.

The South Carolina Grower

Fruit and Vegetable News for Growers and Agribusiness in South Carolina

Tag Archives: Tomatoes

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