Weekly Field Update – 10/12/20

Coastal

Rob Last reports, “Crops are generally looking very well to press with some welcome rain benefiting fall crops.  Whitefly and caterpillar numbers are increasing.  With a few foggy mornings happening over the last week be on the look out for foliar disease pressure to increase given the increase in leaf “wetness”. Plastic and, where applicable, fumigants are applied, ready to begin strawberry planting.  Just a reminder to check plants carefully before planting for crown rots and early foliar pest and disease activity.”

Zack Snipes reports, “We had another wet week in the Lowcountry with 2.5 inches of rain collected at the Coastal Research Station in Charleston.  Things are looking great for strawberry planting in the next few weeks. Be sure to check your plants and roots before you plant them.  Many issues can be solved before plants go into the field. Fall brassicas, squash, lettuce mixes, and root crops are growing and looking great.  We still have whiteflies on many farms.  On most of these farms, spring fields were not terminated once the crop was done which could have led to the explosion of whiteflies we have been seeing this fall.”

Many strawberry growers are putting up fencing BEFORE they plant which drastically enhances the efficacy of the fencing. This fence is about to be baited with a metal tab and peanut butter. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Last week was warm and we saw a heavy dew most mornings. We also had some pretty decent rain come through over the weekend. This warm, moist weather has disease increasing fairly aggressively on some crops. Powdery mildew and downy mildew on cucurbits are pretty rough right now. Pecan shucks are opening and nuts are falling from the earlier varieties like Pawnee and Excel. Strawberry planting should begin this week.”

The shuck has opened on this Excel pecan . Photo from Justin Ballew.

Pee Dee

Tony Melton reports, “Still planting processing greens mostly kale and collards because they are a little more resistant to winter cold.  Greens are rapidly growing.  I have already seen some Reflex damage from carryover from last year.  Personally I think it affects roots and keeps them from taking up nutrients and the damage is very similar to magnesium and boron deficiency – so I always recommend applying Epsom salts and boron to combat the problem and it usually works.  Strawberries are going into the beds. Since many are using vapam or k-pam, make sure that enough time is allowed for the fumigate to escape before planting.  Many do not fumigate anymore so don’t forget velum, nimitiz, and majestine are available for nematode control.”

Upstate

Weekly Field Update – 10/5/20

Coastal

Zack Snipes reports, “The cooler weather and lots of rain have brought out the diseases. I saw some watermelon diseases last week including gummy stem blight. We need to protect our foliage just a few more weeks to finish off those melons so keep at the spray programs if you can.  Whiteflies continue to hammer us in all crops this fall. Strawberry planting is just about upon us. Rains and wet ground have slowed some farms from laying plastic. Remember that preplant fertility and herbicides are critical to spring success. Spartan and Devrinol  are the only two preplant herbicide options this late in the season. Other products require a 30-day wait period. Let me know if you want me to come check your strawberry plugs before you plant them.”

Gummy stem blight on watermelon foliage. Photo from Zack Snipes.

Rob Last reports, “Fall crops are looking good in this area with good development in brassicas and beets.  Insect and disease activity remain moderate however with cooler weathers and rainfall scouting will be critical to success for these crops.  Adult moths are very active at present so be on the lookout for eggs and caterpillars. Plastic is down and awaiting strawberry planting in the next week.”

Growers are ready for strawberry planting. Photo from Rob Last.

Midlands

Justin Ballew reports, “The weather has been pretty fall-like and enjoyable over the last week. The cooler temperatures and high amounts of recent moisture have diseases like powdery mildew, downy mildew, and anthracnose increasing. Caterpillar activity has increased in the last week as well. Be sure to rotate modes of action when spraying for caterpillars. Strawberry growers are ready to plant and will probably start within the next week.”

Powdery mildew has been picking up on fall cucurbit crops. Photo from Justin Ballew.
Adult diamondback moth that just finished pupating on a collard leaf. Photo from Justin Ballew.

Sarah Scott reports, “Daytime temperatures have been mild with cooler night temps. Early last week areas saw anywhere from trace amounts to 2 inches of rain. Low spots in fields may remain wet and this could lead to potential problems.  Peppers are looking good as well as eggplant and late squash. Brassica crops are having some issues with aphids causing leaf curling.  Pecans are beginning to fall as well. Scab seems to be particularly bad this year,  most likely because of wet weather during critical spray times for fungal management in late June and July. 

Pecan scab has been rough this season. Photo from Sarah Scott.

Pee Dee

Tony Melton reports, “Greens are growing fast with cool temperatures; however, beans, peas, pickles, and sweet potatoes have slowed down with these temperatures.  Most sweet potatoes need to find a home.  We are using a lot of potassium phosphide to keep down root rot especially on greens.  Most growers also use it as a dip for strawberries transplants or put through drip system as soon as they plant.  Getting ready to plant strawberries as soon as the transplants get here.”

Upstate

Kerrie Roach reports, “Clear skies since Tuesday with cool fall temperatures at night and warm days has consumers looking for all things fall. Growers with pumpkins, gourds, mums, corns stalks, and/or anything fall related have been busy keeping up with demand. Agritourism demand/opportunities has picked up significantly in the last few weeks. Apples are in peak season with Stayman being one of the current varieties available.”

Andy Rollins reports, “Upstate peaches are finished up for the year but muscadines are still being harvested although slowing some and strawberry planting is in full swing. I was called to examine poorly growing peach trees at an upstate farm. The majority of trees were dying from the most devastating disease of peach ‘Oak Root Rot.’  There was gumming at the base and I was fully expecting a greater peach tree borer problem but closer examination and cutting of the below ground bark revealed the Oak Root Rot fungus growing at the base of the trees.  When pushing your older peach trees up be sure to examine the main roots for the sign of this disease which is the white to yellowish fungal growth deep inside of the bark below the soil level.  There are a few other fungi that can have a similar symptom but they tend to grow just on dead tissue and don’t grow as deep into the wood of the tree.  There are some things you can do about it, but proper identification comes first.”

Gumming and yellowish white fungal growth at the base of a peach tree from oak root rot. Photo from Andy Rollins.
Poor tree growth as the result of oak root rot. Photo from Andy Rollins.

Weekly Field Update – 8/31/20

Coastal

Zack Snipes reports, “We had between 4-6 inches of rain last week with daily thunderstorms.  Growers are working the fields getting ready for the fall crops to go in.  If it happens to rain on Wednesday night, then you should tune in to our Strawberry 101 class from 6-8PM.  We will be discussing economics, seasonal timeline, varieties and common mistakes, and fertility.  This is an excellent opportunity to learn about growing strawberries.  You must register ahead of time to participate.

Midlands

Justin Ballew reports, “After some rain early in the week, the weather turned dry and the temperatures and humidity reminded us that summer isn’t over yet. Fall crops are continuing to progress well, though we are continuing to see a fair amount of disease like anthracnose, downy mildew, and bacterial spot due to the recent wet conditions. Caterpillar populations are climbing on fall brassicas as well. In scouting a field trial, I observed diamondback moths, cabbage loopers, and armyworms. Keep a close eye out and be sure to rotate chemistries when you start spraying.”

Anthracnose spots on a cantaloupe leaf. Photo from Justin Ballew.
Cabbage looper on a collard leaf. Photo from Justin Ballew.

Sarah Scott reports, “Peach season has wrapped up in the Ridge and post- harvest fertilizer applications are being applied. Fall vegetable crops are looking good as we received some decent rain fall over the past week. Hot temperatures have had some effect on lower seed germination of some brassicas.”

Pee Dee

Bruce McLean reports, “Harvest time is finally upon us. Sunshine and warm temperatures is doing the trick for giving growers that final push for ripening the muscadine crop. Crop is looking good, but some bitter rot and ripe rot is starting to show. Brix for Carlos and Noble is averaging around 13.5%. Doreen is still a little ways from being ready to harvest, but it won’t be long.”

Grape harvester picking muscadines. Photo from Bruce McLean.

Tony Melton reports, “So wet in areas it is hard to spray peas for curculio some are having to use airplanes.  Harvesting sweet potatoes for processing and yield is good.  Planting greens for processing.  Harvesting pickles but stopped planting this week.  Still harvesting processing peppers but harvesters are getting real tired.”

Upstate

Kerrie Roach reports, “Heavy rains, humidity and continued high temperatures over the last week have continued an increased trend in disease incidence across the board in both vegetables and fruits. Growers need to be proactive to stay ahead of diseases (and insects) by scouting often and well. We are finishing out the peach season with late varieties like ‘Big Red’. Apples are gaining steam and early varieties are looking and tasting great. Overall the production seems to be on target for a significant increase over last season.”

Weekly Field Update – 8/3/20

Statewide

Dr. Matt Cutulle reports, “Hurricanes or tropical storms can lead to increased seed dispersal from seeds that can be transported by wind and water. Two notorious weeds that come to mind when planning for hurricanes are Horseweed (Conyza canadenis), which due to lightweight seeds and plant architecture can be dispersed for miles during wind storms. A troublesome weed that can be dispersed through water (overflowing irrigation ditches, river surges etc.) is curly dock (Rumex crispus) due to the bladder-like structure of the seed. If you have access to a flame weeder or maybe Gramoxone it might be a good idea to get out to any fallow fields right now and start torching weeds with seed heads prior to this incoming storm to prevent unwanted widespread dispersal of weed seed.

Coastal

Zack Snipes reports, “We are anxiously awaiting to see what Hurricane Isaias will do today and tonight.  Hopefully, we will be spared of heavy rains and winds.  Some rain from the storm would not be a bad thing as many fields are dry.  I have been finding some leaf spots in rabbiteye blueberry, which is common for this time of year.  What is unique about the leaf spots is that they have caused the variety Tifblue to shed its leaves and then attempt to grow out more leaves.  The plant is weak and nutrient-starved so the new leaves are very small and red.  You will see red shoot flagging symptoms on Tifblue but no other varieties.  The other varieties will have the same leaf spot but they will still hold onto their leaves.  Increased fungicide applications between bloom and harvest should help with management of this disease and increase yields on Tifblue and other cultivars.”

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Fungal leaf disease on Powderblue that keeps its leaves despite having an infection. Photo from Zack Snipes.

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Small, red leaves on Tifblue that are a symptom of leaf shedding and regrowth as a result of a fungal leaf disease. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Some of the midlands got some heavy rain this past week, while others remain dry as a bone. Parts of Lexington had a strong storm come through Wednesday night that washed out areas in some fields and left ponds in others. We will have to replant some areas where fall crops had just been planted. The weather has cooled of slightly since. Aside from that, folks are still prepping fields and planting fall tomatoes, peppers, and brassicas. We’re still thinning pecans also. For anyone planting strawberries this fall, now is a good time to start taking soil samples.”

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This field in Lexington had some large areas washed out by the storm that came through Wednesday night. Fall brassicas had just been planted and some areas will have to be replanted. Photo from Justin Ballew.

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A pond that formed in a field in Lexington during the rain Wednesday night. The geese aren’t mad about it (upper right side of the pond). Photo from Justin Ballew

Pee Dee

Bruce McLean reports, “Most vegetable and fruit crops look surprisingly good for the amount of heat we have had recently. Sweetpotatoes are growing very well. Peas, squash, zucchini, cantaloupe, watermelons, okra, and cucumbers are all looking good and harvesting good quantities. Downy mildew is still showing up on cucumbers, and powdery mildew on squash and zucchini. Sweet corn and butterbeans are wrapping up. The blueberry crop is finished. Muscadine grapes are looking very good. Wine/juice muscadines are just starting to color (maybe around 2-3%) and should be ready to begin harvest in about three weeks. Fresh market varieties should be just getting ready to harvest now on the earliest varieties. Grape root borer (GRB) activity was high this past week, with some traps capturing 50+ moths. Too late for any type of treatment For GRB. Just monitor and plan for control next year. Powdery mildew damage is starting to show up in the vineyard. No signs of fruit rot yet. Stink bug damage has been very light in vineyards with a strong spray program.”

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Damage from powdery mildew is starting to show up on muscadines. Photo from Bruce McLean.

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Mighty nice crop of ‘Carlos’ muscadines. Photo from Bruce McLean.

Tony Melton reports, “All processing peas are harvested for the spring crop, but we have some cowpea curculio because of uneven crop due to excessive rain.  Fall cowpea crop is planted or is rapidly being planted.  If they found seed, farmers have already planted fall butterbean crop.  Getting ready to plant fall brassica crops.  Hopefully, all vegetable growers sprayed potassium phosphide on all vegetable crops before all the rain comes for root rot control.”

Upstate

Kerrie Roach reports, “Rain has still been spotty around the Upstate, so irrigation has been extremely important for vegetable production. Storm tracks are showing that the Isaias will bring some relief for the entire area. Early apple varieties are beginning to ripen, but sugar levels are still a little low. Blueberries are about finished for the season and peaches are hitting mid-stride. Cover sprays on tree fruits will be necessary as soon as the rain event passes. Insect pressure is increasing on vegetable crops as we move later into the season and into early parts of fall cropping, so scouting is extremely important.

Field Update – 7/13/20

Coastal

Zack Snipes reports, “Summer crops are all but about done. The afternoon thunderstorms, humidity, and heat have just about finished off the tomato and watermelon crops. Growers are getting fields ready for the fall season now. Consider putting up deer fencing now before crops are planted.

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A field of squash on Johns Island protected with a two-tiered poly fence. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We got some more rain early in the week and the sky was overcast most of the week. Downy mildew finally showed up here in cucumbers. Even though it’s been found all over the coast, it took a while to make it this far inland this year. The dry weather we had most of the month of June may have had something to do with that. Anyone growing cucurbits from now through the fall definitely needs to be applying preventative fungicides. Lots of fields are transitioning from spring crops to fall crops right now. We’re still picking sweet corn, tomatoes, peppers, eggplant, squash, zucchini, cucumbers, etc.”

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

Lalo Toledo reports, “Sweet potatoes are in the ground and thriving. Please be aware of any pest activity and disease activity. Weeds are becoming a problem, especially in organic operations. However, there are several options to suppress weeds. Please contact your extension agent for information on chemical and cultural practices. Hemp is having trouble taking off with so much heat and weeds are gaining ground on it. Peppers are doing great with some minor bacterial lesions.”

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Hemp field with nutgrass (organic operation). Photo from Lalo Toledo.

Pee Dee

Tony Melton reports, “Poured rain every day last week – awful.  Processing peas are ready to harvest but cannot get a dry period to burn down to harvest.  Need to get second crop processing peas planted before August if fields will ever dry out – don’t forget to control thrips early and do your best to keep deer out of fields.  Processing tomatoes & peppers are being harvested.  Pickling cucumbers are continually being harvested and replanted.  Sweet potatoes are planted, most have been laid-by, many have vines covering beds, and some are starting to size potatoes.  We may have some insect damage on roots since it is difficult to get bifenthrin applied and plowed-in.  Hopefully, the Lorsban will control insects, and since it is too wet to plow until the rain can wash the bifenthrin into the soil to keep the sun from degrading it.  Don’t forget the boron on sweet potatoes.”

Upstate

Kerrie Roach reports, “Peaches are the showstopper this week in the Upstate! Even with what appears to be late cold damage causing split pits and some varieties not to ripen, the peach crop is still booming. Apples are maturing on schedule and growers should begin harvesting early varieties over the next few weeks. With limited and spotty rain events over the last seven days, irrigation has been vital for vegetable producers…. but heat and humidity (despite the overall lack of rain) has increased the need for fungicide cover sprays, as we’ve seen various fungal activity picking up across the board.”

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Peaches are coming in and are looking great in the upstate. Photo from Kerrie Roach.

Field Update – 7/6/20

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.”

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

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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.”

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

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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.”

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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.”

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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.”

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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

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.

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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.

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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.”

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

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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.”

Downy Mildew Found on Watermelon in SC

Downy mildew was found yesterday, June 17, 2020, in one watermelon field in Bamberg County, South Carolina. All growers should immediately spray watermelon with Ranman, Revus, or Gavel to protect their crops from downy mildew. In addition to direct yield loss, loss of vine cover can expose fruit to sunburn (when the sun comes out again). Growers who find downy mildew in a field should apply Orondis Ultra or Orondis Opti in a weekly rotation with Ranman or Gavel. For more information on downy mildew, see the updated Cucurbit Downy Mildew Management for 2020.

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Downy mildew symptoms on watermelon foliage. Photo from Dr. Tony Keinath.

Field Update – 6/15/20

Statewide

The video below is from Vegetable Weed Specialist Matt Cutulle. It shows a flame weeder attachment killing weeds around the edges of a field. The person walking behind the tractor is using a flame weeder with a propane tank on his back. These are good options for weed control in organic fields.

Coastal

Zack Snipes reports, “It’s the time of year when crops are starting to look ugly.  We are in the middle of tomato harvest and it seems to be a pretty good crop this year.  Bacterial spot is starting to spread up the plants due to a heavy fruit set, perfect weather, the inability to spray, and constant handling by pickers. Keep up with spray programs as the last few weeks of development are critical to size and taste.  Rabbiteye blueberries are coming in strong right now and look really good with the occasional berry having Exobasidum. Stink bug pressure has been very high this year and I’m seeing damage on a multitude of crops.”

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It is critical to know the difference between Southern Blight and Bacterial wilt when managing tomato diseases.  Southern Blight will have a white fungal mat with small “BBs” on the stem. Photo from Zack Snipes.

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Bacterial wilt shows up in the same fields year after year. Photo from Zack Snipes.

Rob Last reports, “In our area, we are seeing some good quality watermelons and cantaloupes coming to harvest.  We are seeing some manganese toxicity related to low pH in both crops.  Also given the sporadic storms we have seen leaf potassium levels have been lower than ideal.  It would be recommended to monitor tissue nutrient levels and adjust fertilizer applications accordingly.”

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Manganese toxicity on cantaloupe leaves appears as round, tiny, tan spots, sometimes with a yellow halo.  This symptom can be misdiagnosed as early downy mildew. Foliar analysis can be used to diagnose Mn toxicity. Photo from Dr. Tony Keinath.

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 On the leaf underside, the halo appears water-soaked (“greasy”). This symptom can be misdiagnosed as early downy mildew. Foliar analysis can be used to diagnose Mn toxicity. Photo from Dr. Tony Keinath.

Midlands

Justin Ballew reports, “We got a little much-needed rain last week. Crops are developing quickly and growers have started harvesting the oldest planted sweet corn as well as squash, zucchini, cucumbers, beans, and what’s left of spring brassicas. Cucurbit downy mildew has not yet been found in the midlands, but it probably won’t be long. Keep applying preventative fungicides.”

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Zucchini almost ready to be picked. Photo from Justin Ballew.

Sarah Scott reports, “Peach season is in full swing. Bacteriosis and brown rot continue to show up in many fields. Warm temperatures during an extended bloom period as well as rain and cold at critical times in the early season are likely the culprits for these issues.”

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Bacteriosis on ripening peach. Photo from Sarah Scott.

Pee Dee

Bruce McLean reports, “Cucumbers are being harvested in good numbers. Squash and zucchini yields are increasing. Sweet corn will be ready to begin harvest in a few days. Disease pressure is increasing in cucumbers, primarily Cucurbit Downy Mildew (CDM). CDM has caused significant damage and severely reduced the crop in two locations. Forecasted rains for the next 7-10 days will make it extremely difficult to spray fungicides (as well as applying insecticides, herbicides, and fertilizer). Fruit crops are being negatively impacted by the weather, as well. Reduced fruit quality is caused by increased disease pressure and wet field conditions. And, the forecast over the next 7-10 days is for more rain.”

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Checkerboard pattern indicative of Cucurbit Downy Mildew on cucumbers. Photo from Bruce McLean.

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Purplish-brown sporulation on the underside of cucumber leaves confirms that it is Cucurbit Downy Mildew. Photo from Bruce McLean.

Tony Melton reports, “Cucurbit downy mildew is increasing rapidly with the rain, glad we started spraying Ranman or Orondis 2 weeks ago. With the rain, ponds have returned to our fields. As one of my vegetable farmers said “Not a good year to be in the Pee Dee vegetable business.” Hundreds of acres of beans, squash, cucurbits, and peas have drowned. Farmers are probably tired of me saying “Potassium Phosphide will help.” Regretfully, on brassicas, the yellowed margined beetle has become established in the Pee Dee, and downy mildew is awful. However, sweet potatoes are growing like a weed (its close kin morning glories).”

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

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.

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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.

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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.”

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

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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.”

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

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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.”

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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.”

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

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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.”

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