Weekly Field Update – 12/13/21

Today’s update will be the last of 2021. We will take a short break for Christmas and get started again on January 18th, 2022. We want to wish everyone a happy and safe holiday and we look forward to a great 2022 growing season!

Coastal Region

Rob Last reports, “Pest and disease activity remains low in the area.  Disease pressure may increase following some welcome rainfall last week.  Remember to keep scouting.  I would also like to wish everyone a very Merry Christmas and a Happy New Year.”

Midlands

Justin Ballew reports, “We finally got some much-needed rain in the Midlands. Temperatures turned cooler towards the end of the week, but the previous warm weather allowed a few strawberry plants to push out some blooms. This is a good time to remind folks to periodically sanitize dead leaves and blooms from the plants. Once a leaf or bloom dies, it becomes a great source of Botrytis inoculum. Now is also a good time to pull any weeds that are coming up in the plant holes. It’s best to pull them before they become big enough to outcompete and reduce the growth of the strawberry plants. Most plants I’ve looked at still have only one crown, but I am starting to see some plants develop a second. Plants are developing slowly, but at least we’re not seeing any real disease or mite issues.”

The recent warm weather caused a few plants to develop blooms. As the cold kills these blooms, it will be important to remove them from the plants to keep them from becoming a source of Botrytis inoculum. Photo from Justin Ballew.
Be sure to remove weeds from the plant holes so they do not outcompete the strawberry plants. Photo from Justin Ballew.

Upstate

Kerrie Roach reports, “Things have officially settled down with disease and insect pressure remaining fairly low for winter crops. Dormant pruning for tree fruits has begun and will continue over the holidays. Pruning out dead, diseased and damaged as well as unproductive wood will increase the health and production of the trees overall.”

Here’s a great video from NC State Extension on pruning mature peaches: https://www.youtube.com/watch?v=u42z2WuC4Nw

Here’s a great video from University of Tennessee Extension on pruning apples: https://www.youtube.com/watch?v=IEFbZTEcUeY

Weekly Field Update – 11/1/21

For anyone looking to diversify their operation, check out this week’s virtual program on cut flower production. The program will be this Wednesday (11/3) from 12-1pm. Click here to register.

Coastal Region

Rob Last reports, “Following the welcome rainfall last week, crops are looking good. The precipitation will help establish strawberry plants in the area because a lot have only recently been transplanted. Fall brassica crops are developing well, with pressure from diamondback moths being moderate. There are also isolated incidences of whitefly in brassica plantings. The best policy is to scout thoroughly and regularly allow decisions on applications to be made quickly.”

Zack Snipes reports, “Cooler temperatures showed up this past week along with some rain. Everyone is busy planting strawberries. We are a few weeks behind this year but overall the plant quality looks good. Many growers dipped plants prior to planting to prevent crown rot pathogens. One common issue that I have seen this year, and every year, is planting crews planting plants too deep. Although it may not seem like a big deal, planting too deep will cause plants to be small and have reduced yields. You still have time to walk the fields and lift plants up a bit. Bananas and citrus are just about ready to pick in the Lowcountry.”

A Meyer Lemon just before harvest. Photo from Zack Snipes.
A nice cluster of SC bananas. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Temperatures were a little cooler last week and we got some much-needed rain. Strawberry planting has finished now and plants are starting to push out some new leaves. We have seen some plants that were planted a little deep and some that settled too much after transplanting, so be sure to go through the fields and gently pull these plants up to the correct height and reform the soil around them. The best time to do this is before the plants have produced tons of new roots. It’s going to be cooler this week and plants are already a little behind from being planted late. Therefore, growers may want to consider using row covers this month for 2-3 weeks to increase growing degree days and promote growth. There is a great article in the latest NC Strawberry Association Newsletter (pages 6-8) about using row covers in the fall.”

Strawberry plants are starting to push out new leaves. Photo from Justin Ballew
New roots seem to be developing pretty well so far. Photo from Justin Ballew.

Pee Dee

Bruce McLean reports, “Last week’s rain helped to moisten up the soil a bit, but we are still pretty dry across the Pee Dee. Fall vegetable crops are looking good for the most part. Spider mites, aphids, and stink bugs have been very active. Last week’s showers likely knocked back the aphid and spider mite population some, but they will come back. Be sure to actively scout for them. Strawberries are finishing up being planted, and are looking good. Much of the strawberry crop is a little late this year. Be sure to monitor soil moisture (…since it is rather dry), making sure it doesn’t get too dry underneath the plastic. Also since spider mite activity has been up, it would be a good idea to scout for spider mites on strawberries and treat accordingly if mite pressure becomes high enough.”

Fog and Downy Mildew on Collards

From Clemson Plant Pathologist Tony Keinath.

Foggy fall mornings are nature’s warning that conditions are favorable for brassica downy mildew to get started on collard and kale.

Downy mildew sporulation (white masses) on the underside of a collard leaf. Photo from Dr. Tony Keinath.

Remember that because downy mildew affects the harvested, edible portion of the crop, control practices must be very effective to increase yields. Use the following practices to maximize control:

1. Rotate crops to new fields every year. Brassica downy mildew is believed to survive in soil.

2. Check lower, older leaves for angular yellow downy mildew spots on the top of the leaves and black lesions with white downy mildew growth on the bottom of the leaves. Even lesions 1/8-inch in diameter can produce spores.

Yellow downy mildew lesions on the top side of a collard leaf. Photo from Dr. Tony Keinath.

3. Make the first fungicide spray when the first foggy morning is predicted. Fog means the leaves will stay wet all night and a good part of the morning. The lack of sunshine on foggy mornings also allows downy mildew spores to stay alive longer than on sunny mornings, when UV light will kill them in about 24 hours.

4. Potassium phosphite is a very effective, economical alternative fungicide against brassica downy mildew. It is probably “good enough” by itself during sunny periods without rain. Note that it is not labeled for certified organic production.

5. During rainy periods, rotate effective conventional fungicides, like Zampro or Presidio, with potassium phosphite. Fungicide rotation is critical for leafy brassica greens left in the field for more than 2 months when leaves are cropped repeatedly. Zampro may be applied only 3 times per crop. Presidio may be applied 3 times at the 4-ounce rate or 4 times at the 3-ounce rate.

For more info on brassica downy mildew, see Dr. Keinath and Tim Bryant’s article in the latest issue of the Clemson IPM Newsletter.

Weekly Field Update – 10/11/21

Statewide

There are some reports that anthracnose may be issue in strawberries this year. In addition, we are continuing to look out for the new disease, Neopestalotiopsis. Clemson Plant Pathologist Guido Schnabel has recommended applying Zivion S (natamycin) via preplant dip to help prevent these diseases. Dr. Schnabel provided the following instructions:

Mixing Instructions. Add Zivion S while stirring to the volume of water to be applied, or to a smaller volume that is then added to more water to make the expected final volume. Continuously stir the treatment solution unless it is to be applied immediately.
Application Time. Apply prior to plant as a preplant transplant root or whole plant dip treatment. Do not apply after or to harvestable commodities.
Application Rate. Root or whole plant dip: mix 6-12 fl. oz. (0.04 – 0.08 lbs a.i.) of Zivion S per 10 gallons of water. Dip plants for a minimum of 2 minutes, but no more than 5 minutes. Plant treated plants after dip application.

To find Zivion contact Nelson Jameson at 800-826-8302.

Coastal Region

Rob Last reports, “We are progressing well with preparations for strawberry planting. Some Plants are due to be delivered this week. Remember, if fumigants have been used, check to ensure the products have dissipated to prevent damage to the transplants. The same is true to make sure planting restrictions on any pre-emergence herbicides applications are observed. Always refer to the label. Finally, remember to check your plants carefully for pest and disease inoculum from the nursery. Planting any disease or pest-infected plants will lead to a more challenging. If you require any help, please reach to Extension Agents.”

Zack Snipes reports, “I thought I had moved to Seattle last week with all the rain and dreary weather. We have a good week of weather coming up and I expect that everyone will be busy in the fields transplanting greens, finishing laying plastic, and continuing the harvest of fall crops. Watermelons, squash, and winter squash are being harvested this week. Downy mildew is loving this weather and is on basil, squash, cucumbers, winter squash, and cantaloupe. I have seen many freshly transplanted fields with black rot in brassica. This disease shows up every time we plant brassica. It is essential to transplant quality transplants. If your transplant supplier is sending you diseased plants, then visit our Seed and Transplant Supplier list to find a new supplier. You might be surprised how big of a difference it makes. Carolina Farm Stewardship Association is having a webinar this week on Tuesday, October 12 at 12pm on Ginger and Tumeric production in a high tunnel. Please email zbsnipe@clemson.edu for link and passcode.

Black rot with its characteristic yellow “V” shaped lesion. Photo from Zack Snipes.
Transplants that are yellow and have black rot symptoms will not yield like healthy plants. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We finally saw some sunshine this past weekend after a pretty rainy week. Caterpillar pressure has been high and lots of treatments have been going out. I’ve been seeing a decent amount of pathogenic fungi developing on diamondback moth caterpillars due to the wet conditions creating the perfect conditions for development. We’ve had a couple acres of strawberries planted and ordinarily we would be planting full steam ahead now, but strawberry plants are late coming in this year. Lots of folks are being told it will be next week before their plants come in. I’m also hearing reports that anthracnose may be a problem from nurseries this year. As a result, we are strongly recommending a fungicide dip on transplants before planting to combat this and any potential infections from the new disease Neopestalotiopsis. See Dr. Schnabel’s comments about Zivion above.”

This diamondback moth caterpillar’s corpse is covered in white fungal growth. The recent wet conditions have provided the perfect environment for entomopathogenic fungi development. Photo from Justin Ballew.

Phillip Carnley reports, “Cucumbers are finished in Orangeburg and Calhoun counties. Fall greens are in full swing with some pressure from DBM with the occasional looper. Growers are bedding strawberry fields and applying their pre’s. We have seen heavy infestations of gummy stem blight in fall watermelons, as well as spider mite damage in blackberries.”

Gummy stem blight has been bad in watermelons this fall. Photo from Phillip Carnley.
Yellowing from spider mite feeding in blackberry. Photo from Phillip Carnley.

Sarah Scott reports, “Tree removal and field prep for new peach installations are happening around the ridge. Strawberry plants are being planted now and got a good watering in with last weeks rain. Fall vegetables are looking good, growers should keep up with scouting for disease issues in the field following the week of wet and humid weather.

Tree removal and preparations for new planting are going on now along the Ridge. Photo from Sarah Scott.
Fall tomatoes are looking great. Photo from Sarah Scott.

Upstate

Andy Rollins reports, “I am busy scouting new strawberry plantings this past week. Be on the look out for leaf diseases of plants but also check roots thoroughly for discoloration. When planting make sure crowns are still visible after planting. We are also preparing ground for new peach production going in. We are still picking a few muscadines, but that will be finishing pretty soon.”

Fungal infection on a newly planted strawberry leaf. All plantings need to be looked after carefully for the new disease Neopestalotiopsis. Photo from Andy Rollins.

Weekly Field Update – 9/27/21

Coming up this Saturday (10/2/21) is a Waste Pesticide Collection Event held by the SCDA in York. Take a look at their news release here and take advantage of this event if you have any pesticides sitting around that you don’t expect to use.

Coastal Region

Zack Snipes reports, “We have had plenty of rain as of late in the Lowcountry. Many growers could not get in the fields due to fields being soggy. We have some beautiful weather coming this week so I expect a good bit of ground to be prepped and planted. We have plenty of moisture in the soil so those preemergent herbicides should have great efficacy if put down properly. I am seeing some odd yellowing symptoms of watermelon vines that lead to a collapse in the plant. We sent off samples to the Plant Diagnostic Lab. If you are suspicious of a plant disease, we can identify the disease for you. I also received a few calls this week about greenhouses. Before buying a greenhouse, consider retrofitting a shipping container. Thousands of transplants can be grown in a very small space which saves you money on your heating and cooling bill.”

A retrofitted shipping container for growing vegetable transplants at the CREC. Photo from Zack Snipes.
Thousands of transplants can be grown in near optimal conditions in a container. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We’ve really been enjoying the fall weather here in the midlands. We got some rain and the high temperatures have been in the upper 70s/low 80s. The majority of folks got their beds formed and plastic laid for strawberries last week. I’m getting some reports that strawberry nurseries are facing a tight supply this year. Hopefully, everyone got their orders in early. On brassicas, we’ve seen a significant increase in caterpillar population levels over the last week. That makes now a great time to run a field bioassay to screen for insecticide resistance in diamondback moth populations. Contact your local agent to schedule one.”

Tiny, oval, yellow-colored, diamondback moth eggs on the underside of a leaf of a week-old collard plant. Scout carefully as soon as plants go in the ground. Photo from Justin Ballew.

Phillip Carnley reports, “Brassica production is ramping up in Orangeburg and Calhoun and Clarendon counties. Diamondback caterpillar is making itself known in brassica crops, especially in collards. Make sure to scout early and treat in a timely fashion. If your insecticide program is not showing the desired level of control, talk with your local agent about scheduling a bioassay to assess your population’s resistance to different insecticides. Also, be on the lookout for black rot and other fungal problems in early transplants. Loopers seem to be a non-issue currently but stay vigilant in monitoring. I am still getting plenty of calls for pecans and the majority of the issues are pecan scab and yellow aphid damage, causing nut drop and premature defoliation. Also be mindful to monitor/ test for nematodes, in my area I am seeing population loading due to lack of cultural and chemical control. On blackberries, make sure to harvest in a timely manner and maintain a high level of sanitation, as there is plenty of spotted wing drosophila to go around.”

African Fig Flies (AFF)(with the white stripes) can invade small fruit crops simultaneously with spotted wing drosophila (SWD). Once the SWD cuts a hole in the fruit to lay an egg, the AFF comes along and lays an egg in the same hole. AFF can also invade strawberries and blackberries independent of SWD. Photo from Phillip Carnley.

Pee Dee

Bruce McLean reports, “Last week’s rainfall really helped to moisten dry soils around the Pee Dee. Fall vegetable crops are coming along. Disease activity is low and insect activity is light to moderate. Surprisingly, diamondback moths have not been observed yet. Looper activity has been light to moderate on brassicas and cabbageworms have been observed in some fields. Aphids have been seen, as well. Stink bug activity has been moderate on okra. Okra harvest has begun to slow down, but decent volumes are still being harvested. Wine and juice muscadine harvest is complete, but some fresh market muscadines are still being picked in limited volumes. Most folks have bedded and fumigated for strawberries (… or will be this week). Talking to growers, it sounds like strawberry plants (plug and bare root) are getting a bit scarce… more so than normal for this time of the year. If you’re looking for some plants, you may have to go with varieties that you might not familiar with. Be sure to order early next year to get the varieties and volumes you need.”

Weekly Field Update – 9/20/21

Coastal Region

Rob Last reports, “Fall cucurbit crops, including cantaloupes, and watermelons are ripening and approaching harvest. Disease pressure from powdery mildew and gummy stem blight have really increased significantly over the last week. Maintaining a tight spray program will be key to managing disease. As we look forward to strawberry planting land is being prepared. If you are planning to fumigate, make sure the plant back interval between fumigation application and planting is maintained. A good test can be to plant some lettuce seed in the treated area. When lettuce germinates, the risk of damage from fumigation is reduced. Finally, on any remaining fall plantings, consider using a labeled pre-emergent herbicide to help with weed management. Once the crop and weeds emerge, options are drastically reduced.

Zack Snipes reports, “Land is being prepared and fall crops are going in around the Lowcountry. Early fall crops look better with the slightly cooler temperatures and periodic rain. We are wet in some parts. I am seeing lots of bacterial spot in the fall tomato crop. We have good herbicide management plans for greens, but folks will need to take advantage of pre-emergents now.”

Bacterial spot is bad this fall due to the consistent rain. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “This past week was fairly rainy. There are several fields that are pretty soft, even some sandy fields. Folks are still planting brassicas for the fall and they are looking really nice right now. Strawberry growers are also getting prepped to fumigate and lay plastic. We’ve been seeing a lot of damping off (Pythium) in young cucurbits and some brassicas lately. The wet weather is definitely creating the perfect conditions for this. A few things that can be done to help minimize damping off include planting on plastic beds, planting at the proper depth (just deep enough to cover the plug with native soil), rotating fields wisely (tomatoes are a host for Pythium), and using a fungicide at planting may also make sense when environmental conditions are right for Pythium development.”

When transplants are set deep like the one pictured here, the moisture in the soil creates favorable conditions for Pythium to develop all the way up the stem. Instead, set transplants just deep enough to cover the plug with native soil. Photo from Justin Ballew.

Phillip Carnley reports, “Cucumber production is in its final stages here in Orangeburg and Calhoun counties with most growers close to or in the process of harvesting. There is still a noticeable amount of cucurbit downy mildew, but due to the dryer weather it has been easier to keep in check. Sweetpotatoes are currently being dug with yields looking to be fairly good. There have been a few issues with wireworm damage in sweet potato fields with the majority of damage being seen on the lighter colored tubers. Diamondback caterpillar is ramping up in brassica crops, especially in collards. Make sure to scout early and treat in a timely fashion, if your insecticide program is not showing the desired level of control talk with your local agent about scheduling a bioassay to screen your population’s resistance to different insecticides. Also be on the look out for black rot and other fungal problems in early transplants.”

Holes bored into sweetpotato tubers by wireworms. Photo from Phillip Carnley.

Sarah Scott reports, “We received some heavy rain in areas throughout Edgefield and Aiken Counties last week, up to 2 inches in spots. In preparation for October planting, plastic has been laid in strawberry fields. Brassica crops are being planted as field conditions allow. Late summer plantings of broccoli are starting to get some good size on them. Pepper plants that were put out in August are setting fruit that is starting to size up nicely.”

Strawberry plastic laid and ready to go. Photo from Sarah Scott.
These broccoli plants were put out on September 2. Photo from Sarah Scott.
Fall peppers are sizing up nicely. Photo from Sarah Scott.

Weekly Field Update – 9/13/21

Coastal Region

Zack Snipes reports, “We had a heavy downpour of rain last week surpassing 2.5 inches in some spots. I am seeing downy mildew in cucumbers and lots of gummy stem blight in winter squash and pumpkins. The worm pressure has lessened in the past few weeks. I am seeing lots and lots of black rot in transplanted brassicas. Inspect your plants before planting them to make sure the disease is not coming from the nursery. Once a brassica is planted in the field, there is not much we can do to slow the spread except hope that environmental conditions (rain, humidity) are not conducive to spread the disease. I am also seeing lots of early weed pressure in fall planted crops on both bare-ground and plastic. We have some very good herbicide options to apply preplant. Once you plant the crop, we have very few herbicides that can be used over the top of the crop. Right now is the time to get down strawberry herbicides before the season starts. As the old proverb goes: an ounce of prevention is worth a pound of cure.”

Black rot on collard transplant (V-shaped lesion on the margin) just waiting for the right environmental conditions to decimate your yields. Photo from Zack Snipes.
A healthy stand of sunnhemp shades out most, if not all, summer weeds reducing the weed seed bank. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “We received about an inch of rain (at my house), which we really needed. The temperatures over the last week have been very mild and it has started to feel like fall. Fall crops are doing well. We’re still planting brassicas and keeping an eye on caterpillars. Muscadines are being harvested now. Growers are reporting good fruit quality, but lower yields than last year. This is most likely due to the late cold weather that affected muscadine growers across the state. On pecans, black aphid populations and scab incidence are both high. It appears both of these pests are going to significantly reduce yield on sensitive varieties if growers didn’t stay on top of sprays.”

Pecan scab is severe this year. This disease can cause the tree to abort infected nuts. Photo from Justin Ballew
Black aphids are very small, but their damage is easy to see on the leaves. Photo from Justin Ballew

Weekly Field Update – 8/23/21

If you haven’t already done so, please take a few minutes to fill out a survey share your thoughts with us on Extension meetings. We’ll be using the information collected to help plan meetings over the next year. It will take less than 10 minutes and is anonymous. Click here to get started. Thanks!

Midlands

Justin Ballew reports, “Last week was warm and humid again. Some of our sandier fields got dry enough early in the week that crops were wilting in between waterings. We got a bunch of rain over the weekend, though (a little over 2 and a half inches at my house). Overall, fall planted crops are coming along nicely. Some of the earliest planted fall squash and zucchini is being picked now. We’re still seeing the same disease problems that have plagued us all summer, though growers seem to be managing them fairly well. As far as caterpillars go, I’m seeing mostly diamondback moth and armyworms with a few loopers here and there. Get ready. This could be a high pressure fall for caterpillars.”

Even though we’ve had lots of recent rain, it doesn’t take long for the sandy soil in Lexington to dry out and let the plants wilt. Photo from Justin Ballew.

Phillip Carnley reports, “Not much has changed here in Orangeburg or Calhoun Counties. Its been hot and humid and we’ve had a few untimely showers delaying cucumber harvests. There is still plenty of downy mildew to go around. We are seeing loopers on pickling cucumbers that are ready for harvest. At that stage the loopers should be treated prior to harvest with Coragen, Harvanta, or Radiant. Fall brassica, peas, and tomatoes are just now being planted.  We are seeing increased amounts of scab in pecans this year, due to the rain and humid weather. For insect and disease management in pecans, have a look at the UGA Commercial Pecan Spray Guide.”

Caterpillar damage to fall cucumbers. Photo from Phillip Carnley
Loopers are causing some damage to fall cucumbers in the Orangeburg area. Photo from Phillip Carnley.

Upstate

Andy Rollins reports, “Excessive rains have caused cracking of fruit at several upstate muscadine farms. Powdery mildew is also present but I’m not sure how much of a role it is playing on the cracking part. The powdery is damaging the skin of the fruit. Topsin M is labeled and recommended with Captan but have to wait 7 days to pick so have to watch your PHIs. Also finding some insect pests in peach. Oriental fruit moth and sap beetles have been found last week but only a small amount of affected production. Herbicide control has been difficult this year because all the rain has caused excessive grass growth, especially in new orchards.”

Seeing some cracking of the skins in muscadines in the upstate. Photo from Andy Rollins.
This new grower has done a good job of keeping his understory clean. This will pay off for him in the spring of next year if he can keep up the diligent work. Photo from Andy Rollins.

Weekly Field Update – 8/16/21

Coastal Region

Zack Snipes reports, “Its hot and humid in the Lowcountry. Fall tomato and watermelons are in the ground and enjoyed a week of mostly dry weather. Okra and sunchokes, aka Jerusalem artichokes, are loving this heat. With the exception of those crops, there aren’t too many crops in the ground right now.  I am seeing lots of summer cover crops. I love the idea of using a mixed species of cover crop. One reason is, it spreads out the risk that one of the species in the mix won’t germinate or will be eaten by deer. So by using multiple species, you can almost guarantee that something will be there covering the soil. Multi-species mixes also provide different benefits to the farm. Cowpeas may fix nitrogen while sorghum X Sudan hybrids may be a deer deterrent and shade out weeds.”

A beautiful mixed-species stand of cowpeas and sorghum X Sudan hybrid (sudex). Photo form Zack Snipes.
Buckweat is one of my personal favorites because of its ability to attract beneficial insects and mine potassium from the soil. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “Not much has changed here in the midlands over the last week. Its been warm and humid and we got a little rain a couple times throughout the week. Recently planted fall brassica and cucurbit crops have gotten off to a good start. We are seeing some caterpillar activity already. We are seeing increased amounts of scab in pecans this year, thanks to the rain and humid weather. I’m seeing some black pecan aphids causing damage as well. For insect and disease management in pecans, take a look at the UGA Commercial Pecan Spray Guide.”

Pecan scab is really showing up this year. If growing cultivars with poor scab resistance (Desireable, Pawnee, Kiowa, Oconee), stay on top of fungicide applications. Photo from Justin Ballew.
Black aphid damage on pecan foliage. Photo from Justin Ballew.

Phillip Carnley reports, “It’s that time of year to be on the look out for Southern stem blight (Athelia rolfsii) in hemp. To avoid possible infections of this pathogen, avoid planting in fields that have previously had tomatoes, peppers, eggplant, or peanuts. Crop rotation is your best avenue for mitigation as there are no fungicides labeled for control of Southern blight in hemp at this time. Also be on the lookout for plant stunting from girdling roots. For information on chemicals labeled for hemp checkout the EPA website.”

Southern blight mycelium (white fuzzy looking growth) and sclerotia (small, tan bb-shaped structures) developing around the base of a hemp plant. Photo from Phillip Carnley.
This hemp plant has wilted due to Southern blight cutting off its ability to transport water from the roots to the shoots. Photo from Phillip Carnley.

Upstate

Kerrie Roach reports, “Late summer season crops are still producing in the upstate, but many market producers are starting to lose the disease battle. When something is finished for the season, make sure to remove all parts of the crop. Do not leave diseased plant material in the field. Dispose of the diseased crop in an area far away from your fields or garden. Do not use diseased plant material for compost. Most home compost piles do not reach consistent and uniform temperatures at which pathogens will be killed. Dead plant material harbors insects and pathogens that can and will cause issues for fall season crops as well as next year’s crop.”

Weekly Field Update – 8/9/21

Coastal Region

Rob Last reports, “Generally speaking, we are in the change over period from spring to fall crops, with some fumigants being applied to next year’s strawberry plantings. If fumigants are to be used, make sure soil moisture is good and beds are firm to gain maximum efficacy. One thing we have observed in blackberries and blueberries in the area is the emergence of bark scale. Bark scale is a new pest to South Carolina and has previously been noted in ornamentals. However reports for Asia, where the pest is native, indicate the bark scales can survive on Rubus species.

Bark scale egg sacks and adults. Photo from Rob Last.

The images show the egg sacks and adults of the bark scale. The insects appear white and are very waxy, similar in appearance to mealybugs. The wax coatings can make management complex, preventing insecticides from penetrating the layer to be effective against the insects. The addition of crop oils to the pesticide solution may enhance efficacy by helping to strip off the waxy coatings. In blueberries, adults can be found underneath the exfoliating bark, again making contact with the insecticides more difficult. When crawlers emerge, they will be pink and barely visible to the naked eye, and monitoring will be easier with the aid of a hand lens. We will find crawlers hatching in April or May, with a second flush emerging in late summer. An excellent way to detect crawler movement is to wrap the branches in double-sided sticky tape to help to catch the crawlers. Contact insecticides can be very effective against the crawlers. Insect growth regulators may also be effective for management. Unfortunately, systemic materials such as imidacloprid appear to have little effect. Please get in touch with an Extension Agent to help with identification and management options.”

Bark scales have a waxy coating that helps protect them from insecticides. Photo from Rob Last.

Zack Snipes reports, “It’s wet in the Lowcountry. We are getting heavy rain showers what seems like everyday. This is making it hard to get equipment in fields to spray or prepare for fall plantings. I have seen some watermelon and tomato fields and they look ok considering the rain and soggy conditions. I saw some bacterial spot on pepper and expect to see the same on fall tomato with the rain and humidity we’ve had. Get out your preventative fungicides, if you can. I also saw some leafminer damage on these crops which is unusual in my tenure. It seems plants were impacted a few weeks ago but the new growth looks to be unaffected. Melonworms were found in cucumbers, so get ahead of them.”

Leafminers are showing up on tomatoes on the coast. Photo from Zack Snipes.
Melonworms were found in cucumbers this week. Photo from Zack Snipes.

Midlands

Justin Ballew reports, “This past week was a relatively nice, mild week compared to the week before. We had some rain to start the week and more to finish it out. Planting of fall crops continues and what’s been planted seems to be growing well. I looked at a few fields this week of seedling brassicas and I’m already seeing diamondback moth caterpillars and armyworms feeding. Remember to start scouting as soon as plants go into the ground. It doesn’t take many caterpillars to eat up seedlings and small transplants. Don’t forget we can run field bioassays to screen for insecticide resistance, so call us when you start seeing worms.

Diamondback moth caterpillars are already showing up on fall brassicas. Photo from Justin Ballew
It doesn’t take many caterpillars to eat up these small plants. Photo from Justin Ballew.

Pee Dee

Bruce McLean reports, “Vegetable crops are still harvesting well, for the most part. Other than cucurbit downy mildew affecting cucumbers and some powdery mildew affecting squash, there are no widespread vegetable diseases seen in the fields. Cowpea curculio is still widespread on peas and must be intensively managed (starting prior to bloom) to minimize damage. Spotted Wing Drosophila is still very active in late-season blueberries, with trap counts showing very high capture numbers. Grape root borers (GRB) emergence is starting to increase in muscadines. Trap captures for GRB is on the rise. Much of the state is outside the window of Chlopyrifos application for GRB… except on late harvesting cultivars (more than 35 from application to harvest) and maybe some wine grape cultivars in the Upstate. Pecan weevil emergence is just getting started (in pecans). Ground and lower canopy application of Carbaryl and/or a trunk application of Tanglefoot are effective methods of control. Monitor traps and weevil movement through September (especially after rains). Re-treatment of Carbaryl will be necessary and can be reapplied at (up to) 7 day intervals. Pecan scab is becoming more evident in pecan orchards. Also, fall armyworm numbers have exploded over the last two weeks. This is a pest that can affect a wide variety of crops.

Who is spitting in my muscadine vines? That is not actual spit. It is a sticky, frothy substance produced by the spittlebug for protection from predation. Photo from Bruce McLean.
This tiny insect is the spittlebug (what is inside the frothy spittle on muscadines and other plants). They feed upon the foliage of the muscadine vine and do not cause any noticeable damage to the plant. Photo from Bruce McLean.
Grapevine aphids populations on muscadines can be quite significant in late summer. They feed primarily on the foliage and late flower clusters. They seldom require chemical management except when present during spring bloom. Heavy rains and natural predation usually keep them in check. If extended periods of dry weather occur and their feeding does lead to noticeable problems (or if honeydew and sooty mold become evident on fruit and leaves) an insecticide application may be necessary. Photo from Bruce McLean.