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.

Downy Mildew on Watermelon Found in SC

From Clemson Plant Pathologist Tony Keinath.

Downy mildew was found on watermelon this week in Allendale and Barnwell counties. Although downy mildew does not infect fruit, it reduces sugar content once 1 in 4 leaves (25%) are infected.

Downy mildew symptoms on the underside of a watermelon leaf.

All watermelons should be sprayed with a fungicide effective against downy mildew. See pages 214-215 in the 2021 Southeastern U.S. Vegetable Crop Handbook. Any fungicide listed there can be used except Aliette, Previcur Flex, or Curzate. Do not use these fungicides to manage downy mildew on watermelon, as the isolate on watermelon in 2020 was resistant to them. Gavel, Ranman, and Elumin are the least expensive choices. Growers should apply a downy-mildew specific fungicide this week, a protectant (chlorothalonil or mancozeb) next week, and repeat this sequence until one week before the last harvest. See the following publications for more info on watermelon disease management:

Powdery Mildew on Watermelon

Cucurbit Downy Mildew Management

Watermelon Fungicide Guide

Weekly Field Update – 5/24/21

Coastal

Rob Last reports, “As we mentioned last week, cucurbit downy mildew has been confirmed in cucumber crops locally. All cucurbit growers should be applying downy-mildew specific fungicides such as Ranman tank mixed with either chlorothalonil or mancozeb. Other pests and disease levels in cucurbits remain low. Tomatoes and peppers are developing well with good fruit development and low pest and disease pressure. A little bacterial spot is beginning to show in untreated crops. Applications of mancozeb or copper can help to hold the disease. Note applications are unlikely to “cure” bacterial disease. Fruit crops continue to progress with good quality and low disease. Strawberries are showing a little botrytis and anthracnose, but this is at a low level. Peaches are coming to market along with blueberries and blackberries.

Midlands

Justin Ballew reports, “Dry weather has returned to the midlands. Strawberries have slowed down and while we’re still picking a few, we are seeing very few blooms. The heat we’re expecting this week is likely to cease bloom production. The heat could be a problem for tomato and cucurbit pollination as well, as we may see some blooms die. Brassicas have been growing well. There has been an increase in diamondback moth activity over the last week. If you start seeing large DBM populations on your farms, contact your local agent about doing a bioassay to test for insecticide resistance. This is a great way to figure out which materials may work best on your farm. We don’t charge anything for this service. Don’t forget downy mildew was found this past week in cucumber in multiple places in the coastal plain, so it’s time to start preventative fungicide sprays in cukes if you haven’t already.”

An adult diamondback moth has just finished pupating and has not yet dispersed. Remember, insecticide applications should target the larval form rather than the moths. Photo from Justin Ballew

Sarah Scott reports, “We are in full swing with early variety peach harvest. Some peaches are developing a little smaller in size partly due to previous cold weather events. Something spotted in the field has been some nutrient deficiency. Growers may have been tempted to dial down nitrogen or calcium nitrate applications on peach blocks that suffered cold damage as they thought those blocks would not produce a viable harvest, however this could lead to leaf drop and less reserves for next year’s crop. If you skipped out on some of your fertilization keep in mind yellowing, spotting and leaf drop could occur. A soil application of calcium nitrate at 30lb/acre now and another in late July can help those trees recover some foliage and build up a nutrient supply for next year’s reserve. Be careful if you want a quick result and try foliar applications, as this could burn the leaves and cause more drop that you may not be able to afford.”

Nitrogen deficiency on a mid season peach variety. Photo from Sarah Scott
Discoloration from nitrogen deficiency looks similar to copper burn but has smoother edges and more rounded spots on leaves. A nutrient analysis can be taken around July to determine accurate levels. Photo from Sarah Scott.

Pee Dee

Bruce McLean reports, “Irrigated vegetables are looking good for the most part. Seeing some stress to tomatoes with a heavy fruit load – likely from very low humidity and very high UV. Nonirrigated crops are starting to show some drought stress. Strawberries are starting to wind down. Blueberries are finally starting to be harvested, much later than usual. Blooming on muscadines appears to really stretched out due to the Easter freeze. Early flower clusters on growth from primary buds appears to be somewhat on time. But, flower clusters developing from secondary buds are really behind… possibly 3-4 weeks (easily). Soil is really starting to get dry in many areas.”

Green beans are really coming along. Photo from Bruce McLean
Now is a good time to walk the fields and pull weeds. Over-the-top herbicides are limited for most vegetable crops, and often hand weeding is the only viable option. Vigorous weeds like pigweed can quickly overtake a field. Photo from Bruce McLean.

Tony Melton reports, “The higher temperatures have started to speed-up crops. We will start to harvest pickles this week. Spraying downy mildew fungicides on cucurbits. Some farmers are starting to apply insecticide for pickleworm. They don’t want to put out insecticides this early but they see the gamble of an entire field of pickles being rejected because of 1 pickleworm as too much of a gamble. These farmers think we need a system set-up to detect pickleworm in the southern part of the state to give them a better indication of when pickleworm arrives. Harvesting greens, cabbage, and broccoli as quickly as possible. Started planting sweetpotatoes. Many farmers getting deer depredation permits for peas, beans, and sweetpotatoes. Also, many farmers are applying acephate and dimethoate to control thrips with the added benefits of repelling deer. Peppers and tomatoes are begin to load with fruit. Many farmers still harvesting strawberries.”

Upstate

Kerrie Roach reports, “Things in the ‘Golden Corner’ are looking up for vegetable producers, despite the dismal projection for tree fruit crops because of the cold events in April. For market growers, cool season crops are at their absolute last with 90+ degree temps forecasted for this week. Warm season crops are starting to really get growing, and many growers are starting to see some potential harvests this week. With higher than normal temps projected, make sure irrigation is consistent, scheduled and set for early morning to avoid leaf wetness late in the day and overnight and reduce disease incidence.”

Cucurbit Downy Mildew Found In SC

Cucurbit downy mildew was found in SC this week in Bamberg, Barnwell, and Calhoun Counties. In each case it was found on cucumbers and for now severity seems low. This is about two weeks earlier than in the past couple years.

Downy mildew symptoms on cucumber. Lesions are often limited by the veins in the leaves.
Dark-colored downy mildew spores developing on the underside of cucumber leaves.

If not already doing so, all cucumber and cantaloupe growers in SC should begin applying protective fungicides to help prevent or manage downy mildew. Ranman tank-mixed with a protectant, such as chlorothalonil or mancozeb, or applications of Zampro are good options for protecting plants prior to symptom development. For more info, see Dr. Tony Keinath’s CDM Management publication.

Weekly Field Update – 5/17/21

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 8/24/20

Statewide

Dr. Tony Keinath reports, “For the past few years, Orondis Opti on cucumber and cantaloupe and Orondis Ultra on pumpkin and watermelon have been the best fungicides to manage downy mildew. Based on results from a spring 2020 cucumber experiment at Coastal REC, Orondis is no longer the “silver bullet” it was 2 years ago. In my experiment, Orondis Opti rotated with Bravo controlled downy mildew in the early part of the season, but disease increased significantly during the latter part of the season and ended up higher than expected. Part of the shortcoming of the Orondis Opti/Bravo spray program was the Bravo rotation. Bravo sprayed by itself every other week did not control downy mildew at all, so spraying Orondis Opti/Bravo acted like Orondis Opti sprayed every other week, which was not enough. The labels for Orondis Opti and Orondis Ultra say they must be rotated with another fungicide. For the rest of the 2020 season, use Orondis Opti/Ranman + chlorothalonil on cucumber and cantaloupe, and Orondis Ultra rotated with Gavel or Ranman + chlorothalonil on pumpkin and watermelon. Always use the high rate (2.5 pints/acre) of Orondis products. Note that the mancozeb in Gavel or adding chlorothalonil helps to manage other foliar diseases like gummy stem blight and anthracnose. Yield data and input costs from my experiment are being analyzed to see if spraying Orondis leads to a higher net return despite the higher cost of this fungicide. Results will be presented at the virtual Cucurbit meeting in February 2021 to help growers plan downy mildew fungicide programs for the 2021 season.”

Cucurbit downy mildew continues to spread across the state.

Coastal

Rob Last reports, “Fall crops continue to grow well in the area.  Given the current weather patterns pests and disease are active in some crops particularly where there are volunteers remaining from previous crops.  Vigilance will be required in scouting an pesticide management programs.  If In doubt scout.”

Midlands

Justin Ballew reports, “It’s been cool, cloudy, and kind of pleasant outside this past week, though that has the vegetable crops growing a little slower. We’ve gotten some decent rains in most areas around the midlands as well. Bacterial spot is really showing up on fall tomatoes as a result of all the recent rain. It could be a bad fall for bacterial spot if the weather stays like this. Caterpillars are already out there on fall brassicas. It doesn’t take long once they’re planted. Start scouting, scout often, and rotate insecticides. Remember to contact one of us about screening your farm for insecticide resistance in diamondback moths once you start seeing populations build up.”

Bacterial spot and speck start on the bottom of the plant and can be splashed onto higher leaves and fruit by rain drops. Photo from Justin Ballew.
Start scouting for caterpillars as soon as your fall brassicas are planted. Photo from Justin Ballew

Pee Dee

Bruce McLean reports, “Both fruit and vegetable development has slowed a bit due to cloudy conditions. Sunny conditions needed. Sweetpotatoes are sizing well and will be ready for harvest soon. Fall cucumbers and squash should soon be ready to start harvesting. Fall brassicas are being planted now. Muscadine crop is getting close to harvest. Noble is around 90% ripe; Carlos is around 60%; Doreen is still around 25%. Brix (sugar content) is off due to rain and cloudy conditions. Noble and Carlos brix are averaging around 11% with a low of 9.2% and a high of 15.0%. Doreen is averaging less than 10%. Did find a few Doreen that brix was over 19%… candy. Sunny conditions definitely needed.”

Noble muscadines around 90% ripe. Photo from Bruce McLean.

Tony Melton reports, “Beginning to harvest processing sweet potatoes but some have been stunted and delayed by excessive rain.  Spraying processing peas for cowpea curculio.  Starting to plant processing greens by seed.  Even though lots of rain and having to mud through fields cucumbers for pickles are being harvested and still being planted.”

Upstate

Andy Rollins reports, “Blueberry pruning is best served for the dormant time of year late January-late February.  I met with a commercial grower who was anxious about getting started early partly because he has many plants completely unproductive for the second year in a row. I like to call this revenge pruning as that is the primary motivation. Be careful, you could end up hurting yourself more in the long run. In his case, it was all about light and proper pruning to encourage light down through the canopy. The orignial spacing of Rabbiteye type varieties was very close so we also considered killing every other plant to get more light into the bushes but this would not replace the need for properly selectively removing a few of the oldest canes each year, spacing them out so there is better light penetration. For a detailed explanation, please see NCSU Blueberry specialist Bill Cline’s presentation.”

Field Update – 7/27/20

Coastal

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

IMG_6219

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

IMG_1234

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

Midlands

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

20200723_101151

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

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

Pee Dee

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

Upstate

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

k1.jpg

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

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

IMG_1736

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

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.

IMG_0953

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.”

20180702_140605.jpg

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.”

l1.jpg

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.”

IMG_1775

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

Field Update: 6/22/20

Coastal

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

IMG_0756

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

Midlands

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

20200618_105935

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

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

l1

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

Pee Dee

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

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.

2015-07-13 DM on WM

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