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more moss madness

Hello on this last Friday of May. Me, I’m not mentally prepared for the fact that it will be June on Monday.


On the disease side, we’re still seeing large patch in zoysiagrass but the grass in the centers is starting to recover (see photo). I even had a sample of large patch from a zoysia home lawn, which is not very common. I’m also seeing continued spring dead spot in bermudagrass.

We finally have the first dollar spot activity at our turf research facility, and our first applications for summer trials went down yesterday. I accidentally hooked up the wrong nozzles at first, but we quickly sorted out the problem ("Hmm, why is there so much solution left in the bottle?"), exchanged nozzles, and everything was fine.


I made a few comments on moss last week, and I thought I’d share a few more.

1) How does moss spread?

Most mosses can spread by two mechanisms, vegetative (asexual) as well as sexually.

With vegetative spread, little chunks of the moss tissue physically break off and spread as clones (=genetically identical) of the mother plant. This probably happens on mowers and other equipment as well as rainfall. The first photo is little moss chunks floating in rainwater. That photo was sent to me by my colleague Dr. Derek Settle of the Chicago District Golf Association.

This kind of spread is somewhat analogous to turf pathogens such as Sclerotinia homoeocarpa (dollar spot) or Rhizoctonia solani (brown patch) which do not produce spores but rather spread as chunks of mycelium or sclerotia.

The next photo shows the sexual stage of moss. Moss plants produce male and female gametes which combine to form this small stalk with a capsule at the top. This life stage is called the sporophyte. In the capsule, spores are formed. The spores then disperse and form new gametophytes (the typical cushion-type growth).

2) Where are mosses found in nature?

Most mosses are found in moist environments. The old adage is that if you are lost and can’t determine compass directions, you can look for moss on tree trunks. Since moss prefers shade, the moss is most likely to be on the north side. I’ve never been lost enough to resort to that, but I have seen the pattern.

However, the most common moss on golf courses, silvery thread moss (Bryum argenteum) seems to be happy almost everywhere. It can tolerate heat, drought, and extreme cold. Silvery thread moss is actually a dominant plant species in Antarctica! Throughout the world, it has been found on mountain tops and at sea level. No wonder this stuff can be such a pain. It can thrive anywhere.

3) “Where is Moss Man?”

This question was posted by my colleague Frank Wong. Awhile back, I shared with Frank and some others that while thinking about moss I had a sudden flashback to my youth and the character “Moss Man” on the cartoon “He-Man.”

You can find information about Moss Man on Wikipedia, and I just checked eBay, and you can buy your very own action figure there, unless I beat you to it.

It's a Mix Out There!

With all of the wacky weather we've had in California, we're seeing a mix of spring and summer diseases in the lab here and through reports from superintendents.
Rapid blight and Waitea are still active on Poa greens as is pink snow mold here and there in Northern California.

Anthracnose still hasn't shown up from Poa greens just yet - but has been seen on stressed perennial ryegrass samples from roughs and on a bentgrass green in Idaho.

In this bentgrass case - low fertility contributed to the disease popping up on mechanically or weather damaged turf.

Bermudagrass samples are starting to show up in the lab with decline or other ETRI on the roots. As we get further into the summer transition to bermudagrass, superintendents are starting to see weak areas thinned out by pathogen activity on the roots over the winter. A healthy dose of sun, heat and water will probably get thinned out areas of bermudagrass to fill in, but take note of these areas and see if you can improve compaction, fertility or drainage here; environmental factors that usually contribute to decline, spring dead spot or ETRI damage on bermudagrass.

It's all about your roots: good roots now means less summer stress later
Already, we've been getting samples in the lab showing heat and summer stress. With rapid changes in weather and conditions, greens can go from looking good to looking like crap in a very short period of time. Often the first heat spell will show where you have good roots. The more roots you can put down before the summer heat starts the better. That means additional solid tine aerification, addressing dry spots will handwatering or soil wetting agents and most importantly, adequate nitrogen fertility. Poa/bent greens need at least a quarter pound of nitrogen per 1,000 sq ft/month and even up to half a pound if you have a lot of play or traffic. Give cool season turf enough food to grow now, because when we start going into the 90s and 100s, cool season turf will start to shut down and you may be in trouble if you don't have enough roots or plant mass to make it through the summer.

Spots Galore

Once again the weather is fantastic in the Midwest! Just a week ago we had very low humidity and temperatures hovering around 75 to 80F. This week is a different story. The forecast is calling for cool, wet conditions for much of the week. Consequently, we are seeing a lot of leaf spot on creeping bentgrass. Most the damage is localized in the older leave tissue, however we have seen samples that resulted in serious damage like in the picture to left.

We have observed a leaf spot on segregates of creeping bentgrass in Illinois and Wisconsin for the last couple years. Symptoms typically develop towards the end of May and continue throughout June. Symptoms tend to dissipate once warmer, drier weather sets in during mid to late summer. Fungicides that are usually very effective against leaf spot diseases do not work well against this particular leaf spot. Headway works very well against this disease, but is very expensive if the disease develops on fairways. We attempted to isolate the pathogen last year to determine the causal agent, but we tried too late in the year. This is a disease that we would like to gain a better understanding of, so if you have seen something similar please let us know.

Nothing new to report in Midwest, except for a few reported cases of dollar spot and yellow patch. The soil temperatures are still perfect for preventative applications targeting fairy ring and take-all patch. Some people prescribe to early-season dollar spot applications and those should already be down or put down this week. The first of June usually kicks off the disease season in the Midwest, so maybe next week will be more interesting.

Should I water that in?

This is easily the most frequent question I get from golf course superintendents during the growing season. It is a difficult question, and there isn't always an easy answer.

We know that watering fungicides into the root zone is important for effective control of root diseases. However, in the real world, golf course superintendents apply fungicides to control a combination of root and foliar diseases, but we don't always know what effect watering-in has on foliar disease control.

To answer this watering-in question, you need to identify the primary disease you're trying to control, know where this pathogen attacks the turf plant, and understand how the selected fungicide moves in the plant after application.

In most cases, if a root disease is the primary target for a fungicide application, then it should be watered-in immediately after application. Once the spray dries on the leaves, it will be locked into the foliage and will not get into the root zone. Exceptions to this rule are the true systemic fungicides, like fosetyl-Al and the phosphite salts. These products are translocated downward in the plant and do not need to be watered-in.

The Fungicide Selection Tool, a new feature on our TurfFiles website, can help you select the best application technique for your fungicide applications. After selecting your turf species and the diseases you are trying to control, a list of fungicides is displayed. The list is ordered based on average efficacy against the selected diseases. After selecting a product or products to apply, you are taken to a page that displays mode of action, efficacy rankings, risks for fungicide resistance, rates and application intervals, and application instructions for each selected disease.

Question for 5/24/09: Do diseases appear in straight lines?

Can you guess what caused these symptoms? (Link to answer is below)




Click here to find the answer.

Dollar spot creeping in

Happy Friday,

In between managing all that turfgrass I hope you have some time to enjoy a long holiday weekend.

With some recent sunny, windy weather and temps in the 70’s and 80’s we are starting to see some hot spots on greens. A new graduate student here, who has worked on golf courses since high school, noticed it before I did. Earlier this week we verticut, aerified, and topdressed our research greens. We had some problems last year with thatch buildup/puffiness so we are going to do a better job this year keeping on top of it.

On the disease side, more and more reports of dollar spot activity are coming in. Here in Kansas we often have an early-season epidemic (May-June-early July). Then, it usually fades away in midsummer when we are at peak temps. Dollar spot comes raging back again in late summer/fall. However, sometimes we do see it in mid-summer if it is mild and wet.

Though not technically a disease, moss has been on my mind lately. In 2008, I had a study with my KSU colleague Dr. Jack Fry and Dr. Derek Settle of the Chicago District Golf Association (CDGA), with plots in Kansas and Chicago. We looked at a couple of different moss control strategies with different combos of chemicals and cultural practices. Mowing height was definitely a factor, with 0.156-inch having significantly less moss than 0.125. Two spring applications of carfentrazone-ethyl reduced moss. In addition, two spring sodium bicarbonate treatments (that’s baking soda) knocked down the moss. That’s not a labeled moss product, but it’s interesting, and we are trying it again this year.

The images are of silvery thread moss at the KSU research facility. In the field plot photo you can see the silvery cast that gives the moss its name.

All Quiet on the Western Front (Sort Of)

I just returned from a Hi-Lo GCSA meeting at Desert Falls Country Club out in Palm Desert, CA. Thanks again to superintendent Tom Shephard for hosting the meeting today! The bermudagrass out there is booming but wow, it was 101 degrees out there and it's only May.

It's totally amazing how diverse California weather can be. It's in the 60s on the coast 70-80s in inland valleys, 90s in the Central Valley and 100s in the desert. Going straight east from Santa Monica - you can have about a 40 degree difference within 120 miles. Yowza!

Last week we still had some pink snow mold activity in northern California. Yes - we can get pink snow mold here without snow cover, but that disease should subside as things warm up through this Month. Well - except for northern coastal locations like Pebble Beach and San Francisco - places that always seem to be cool and wet in our spring and summer months in California, which reminds me of that saying that "the coldest winter I ever spent was a summer in San Francisco". Other than that - rapid blight and brown ring patch are still hanging around causing some problems here and there.

Other coastal and inland areas in the mid 60s - 80s should expect to see significant rapid blight pressure while the Central Valley guys should be looking out for "summer" diseases like southern blight, anthracnose and summer patch.

Start Anthracnose Control Now
Anthracnose is probably up there with swine flu when it comes to diseases you want to avoid. Preventive sprays should be started for anthracnose and summer patch when soil temps are regularly above 68 degrees. Start hitting Poa greens now with systemic fungicides to reduce the pathogen populations and reduce the disease pressure later in the summer. Wait unti you get wiped out with anthracnose and you may wish you had swine flu instead.

Whiting Out Weeds
I have to admit - plant pathologists often do things backwards agronomically to encorage disease in our research plots. Amazingly, gettting rid of creeping bentgrass is in Poa is something that makes sense for pathologists studying annual bluegrass diseases like anthracnose and summer patch.

Recently we've been fooling around with making mesotrione (Tenacity) applications on our research greens to get rid of creeping bentgrass. Mesotrione shuts down carotenoid (pigment) production in certain grassy and broadleaf weeds, resulting in some pretty striking effects. According to the label, Tenacity herbicide is considered safe for use on Kentucky bluegrass, centipedegrass, tall fescue, perennial ryegrass, fine fescues and St. Augstinegrass.

Controlling bentgrass in Poa greens is definitely not on the label, but again, plant pathologists do some pretty bass-ackwards things to get good disease.

Signing off from the left coast and until next week!


Watching and Waiting

Well things in the Midwest are starting to appear "normal". We have had quite the weather the past few weeks, with severe winds and significant rainfall. There is very little to report from the Upper Midwest. Most golf courses are on the road to recovery from any winter kill, however there are still some spots here and there.

As I mentioned, the spring storms have been severe and many golf course superintendents find themselves working on tree clean-up. Not much in the way of disease activity in the Midwest. We've had a few reports of yellow patch, leaf spot and dollar spot in Mid to Southern Illinois, but nothing major yet.

However, this is the perfect time for take-all patch and fairy ring preventative applications. Soil temperatures at a Madison, WI golf course were 57F on Tuesday morning. Now is also the time to monitor nitrogen fertility levels if you have a significant stand of Poa annua. Poa has started to seed at a few golf courses and with that expenditure of energy those plants may need some nitrogen. If the plants start to look chlorotic, than a light foliar feeding may be necessary. This has been shown to reduce anthracnose severity by Dr. Bruce Clarke's group at Rutgers University in New Jersery.

It's not too late to prevent fairy ring and Pythium root dysfunction

If you haven't made your preventative fungicide applications for fairy ring and Pythium root dysfunction yet, it's not too late, but it will be very soon.

Although symptoms of these diseases are most common during the heat of summer, we've found that the pathogens are most active during the spring and early summer. Fungicides are most effective when applied during these periods of pathogen activity.

Pythium root dysfunction is a common problem in the southeast on creeping bentgrass putting greens built within the last 10 years. The pathogen infects the roots during the fall, winter, and spring when soil temperatures are between 50 and 75 degrees.

Remember that Pythium root dysfunction is a stress-induced disease. Low nitrogen inputs (less than 3 lbs per year), drought stress, close mowing, and infrequent aerification are common sources of stress that compound the disease. Maintaining a healthy turf plant with sound agronomic practices goes a long way towards reducing problems. All the fungicides in the world will not provide acceptable control of PRD if the turf is continuously stressed.

Preventive fungicide applications should be made in the fall, winter, and spring when average daily soil temperatures between 50 and 75 degrees. For details on recommended fungicide rotations, please refer to our information sheet on TurfFiles. Remember that fungicides should be watered into the soil right away for best results.

We've made excellent progress in fairy ring management over the last 5 years. The DMI fungicides, such as Bayleton, Eagle, Tourney, Trinity, and Triton, have been providing excellent control in the southeastern United States. For best results, these products should be applied when 5-day average soil temperatures are between 55 and 65 degrees. However, as long as they are applied before symptoms appear, they will provide good control in our experience.

Just like with PRD, fungicides must be applied to the soil for best results. Applications should be watered-in as soon as possible with 1/8" to 1/4" of irrigation. We do not recommend tank-mixing the DMIs with wetting agents or soil surfactants, as we've observed reduced control from these combinations. Wetting agents should be applied separately as part of your normal program.

For more information on fairy ring prevention, please refer to the Fairy Ring Disease Profile on TurfFiles.

Weather and golf course diseases

Anytime we talk about any plant diseases, we can't help discussing the disease triangle. A prerequisite for any disease are a suitable host, a pathogen, and the proper environmental conditions. While the presence of a host and a pathogen are important, the current and future weather is usually considered the most important factor (I will save the discussion about the importance of the host plant and pathogen for a future blog).

For golf course superintendents, monitoring the weather is usually high on the priority list of daily tasks. Conditions can change fairly quickly and encourage the rapid development of turfgrass diseases. To assist, turf pathologists have developed predictive models for a handful of turfgrass diseases. While none the models are perfect, they do provide managers with useful information about what diseases may possibly be on the horizon.

As we begin to enter the period in the Northeast where turfgrass diseases become more prevelant, take some time to check out the following site that provides weather-based predictions for various turfgrass pathogens.

Cornell's Forecast

Currently in the field: take-all patch, dollar spot (just starting), brown ring patch, leaf spot, anthracnose basal rot, red thread, and Microdochium patch.

Get ready for: dollar spot and summer patch (preventive applications).

Do you know of other disease prediction websites or services? Post links in the comments!

Happy Birthday Frank!

Our West Coast turfgrass pathologist turned another year older today.

Directly from the man himself, "Frank Wong is 2 x 2 x 3 x 3 today."


update from Kansas

It’s another cloudy, rainy day. The trees are really leafing out and everything is lush and green.

Turf diseases:

On the turf disease side, there’s not anything new going on this week. Same story: large patch in zoysia, spring dead spot, a little dollar spot, a bit of rust, and powdery mildew in shady sites (see image).

Don’t forget about your other plants:

On the golf course, turf is the main attraction, but don’t forget about your trees, shrubs, perennials, and annuals as they can truly make a course special. Here at Kansas State I work with trees and ornamentals along with turf, and I see a lot of dead and dying plants every year. Right now a lot of people are putting in new plantings before the summer heat comes along. If you are installing new plantings be sure to select the right plant for the right place, considering sun, shade, exposure to wind, drainage, pH, soil type, etc etc. When it comes to trees and shrubs make sure you use the proper planting technique. Every year I see trees and shrubs go down because they were doomed from the start from poor planting (too deep, too shallow, girdling roots, etc).

Rapid Blight in the West

Rapid blight continues to be a problem for us in the west - year round on annual bluegrass in California, in the spring and fall on annual and rough bluegrass in Nevada and during the fall overseed on rough bluegrass and perennial ryegrass in Arizona.

A few weeks ago - working with Colorado State University's Tony Koski and Ted Tisserat, we confirmed the first incidence of this disease in Colorado on a course where it had caused significant damage to 9 annual bluegrass greens. The damage was most evident after a spring blizzard and we suspect that irrigation water high in sodium accumulated from winter snow melt is to blame.

The take home message here is that this pathogen can pop up and cause problems when salt levels are elevated on cool season turf and rapid blight is likely more widespread than we'd like to be. Unfortunately - this disease is hard to diagnose without a microscope and assistance from a diagnostic laboratory is needed.

One of the most effective tools that can be used to control this disease is just monitoring soil salinity levels with a handheld TDS meter, such as the Oakton EC tester - readings above 0.6 mS/m in the upper inch of moist soil and thatch (equivalent to 2.4 dS/m based on saturated paste extract analysis) often indicate you are at salinity levels conducive for the development of this disease.

Basically, monitoring is performed by wetting the area with potable, fresh water and jamming the probe into the soil and thatch under the canopy.

Work by Mary Olsen at Unversity of Arizona has shown that the rapid blight pathogen grows best at sodium levels above 2 dS/m (1280 ppm) and that sodium is the primary salt that is needed. Other cations like calcium and potassium don't appear to have an effect on the pathogen. Leaching sodium out of soils with adequate water and calcium (to displace sodium in the system) is the 'cure' for rapid blight. Fungicides like mancozeb, Compass and Insignia are effective in halting the disease, but often the disease will return if salt levels are high.

For more information on this disease - check out the excellent review article on rapid blight avaliable here:

Signing off from the left coast - see you next week!

Odds and Ends

Parts of the Midwest have been relatively cool and wet and as a result we have seen a lot of Microdochium patch in our diagnostic clinic. If the weather remains cool and wet than Microdochium patch can become fairly severe and may warrant a fungicide application. There are many fungicides that work well curatively against Microdochium patch. For more specific information please consult our webpage: At our webpage you can access our research reports, from which you can see what chemicals performed well in our snow mold trials this spring.

A few courses in Wisconsin have reported some minor leaf spot symptoms on creeping bentgrass. After talking with the superintendents, the symptoms were not severe enough to justify a fungicide application. Many superintendents throughout the Upper Midwest are still dealing with winter injury of Poa annua. One particular superintendent has implemented a fairly aggressive cultural program to encourage re-growth. He has aerified and dimple tined greens, along with a fairly heavy fertilization and a light topdressing. He has seen significant improvements and is well on the road to recovery.

Finally, Derek Settle at the Chicago District Golf Association has observed brown ring patch at several locations in the Chicago land area. Outside of Derek’s report, we have not heard reports of brown ring patch anywhere else in the Midwest yet. If you are struggling with brown ring patch or suspect you may have this disease please feel free to contact us. You can find our contact information on the website posted above.

Is your turf juicing?

Last week, Manny Ramirez became the latest in a long line of baseball stars to be exposed as a cheater. When reports surfaced that he had failed a drug test, Manny resorted to the typical excuses: someone told me to take this stuff, I didn't know what was in it, I didn't know it was illegal, etc.

Yeah, right.

You might ask yourself, "How could a professional athlete, who earns a living with his body, take a drug or supplement without knowing what's in it, what side effects it has, or how it might interact with other supplements?"

It's a valid question, but it begs another question. If you make your living by growing healthy turf, why would you apply something to your greens without knowing exactly what's in it, what side effects it might have, and how it might interact with other management practices?

And yet, many golf course superintendents do just that by using biostimulants, turf enhancers, biofungicides, and other miscellaneous products. Many of these products have unknown ingredients, haven't been thoroughly researched, and are of questionable benefit. When you boil it down, they aren't any different from the plethora of diet supplements advertised on late night infomercials.

Before using these products, consider a couple of things. First, in many cases the positive response you see is nutritional. So why not apply fertilizers instead, so you can control how much of each nutrient is delivered? 

Second, some products contain plant growth hormones, which can negatively interact with your growth regulator, herbicide, or fungicide programs. It just doesn't make any sense to apply a gibberellic acid (GA) inhibitor like trinexapac-ethyl and then turn around and apply an unknown amount of GA from a biostimulant.

I am not saying that all biostimulants, turf enhancers, and biofungicides are bad. There are some good products out there that have their place. But I do encourage you to be an informed consumer by demanding to know exactly what nutrients and hormones are in the products you purchase, asking to see research data that shows the products are beneficial, and reviewing the research carefully to make sure it is relevant to your situation.

You wouldn't take a pill without knowing what's in it, don't ask your greens to do the same thing!

Don't neglect your nozzles!

As your college interns start to filter to the course from academic studies, now is the perfect time to fire up the sprayer in preparation for the 2009 season. This gives you the opportunity to ensure that your equipment is in proper working order AND gives the students the opportunity to get hands-on experience with calibration techniques that many have only heard about in the classroom.

Many websites and books are available to assist in the calibration of your equipment. In preparing for this update, I also came across a calibration software package that TORO offers for download from their website. While calibration of your equipment is important, another factor that should not be overlooked are the nozzles that you select to control turfgrass diseases.

Research conducted in the past few years has revealed that nozzle selection plays an important role in the suppression of turfgrass diseases (Read GCM Article). In particular, the control of foliar diseases such as dollar spot and brown patch can be improved by selecting nozzles that improve spray coverage. One major problem with this is that nozzles producing excellent coverage generally have increased potential for drift. Our research has shown that utilizing nozzles that incorporate air into the droplets (air induction) provide the best of both worlds. Here are some keys to improving disease control.

1. Consider the location of the pathogen. Fungicides for root diseases generally need to be applied in greater volumes of water (>2.0 gal/1000 sq ft) and/or watered-in following application. Foliar pathogens should be suppressed with a nozzle that produces excellent coverage.

2. Air induction nozzles provide excellent control of foliar pathogens and have relatively low potential for drift. TurfJet nozzles (typically supplied with many sprayers) generally offer poor disease control, especially where lower water volumes (~1.0 gal/1000 sq ft) are utilized.

3. Nozzles should be changed at least once per year (twice per year in some cases). Always buy an extra nozzle to use as a comparison when determining if your nozzles need to be replaced.

Update from Kansas


It's Friday, it's Friday, and a beautiful day it is here in Kansas. Lucky me, I have some field work scheduled for the day.

The spring rains are continuing. Large patch of zoysia is popping up all over, including in our research plots (see image). While pulling some samples of large patch in zoysia at a golf course, I also found some rust (see image).

Now that the bermudagrass is greener, symptoms of spring dead spot are becoming more apparent.

Though dollar spot is not yet active at our research facility, I heard from a superintendent that they had dollar spot active on most greens.

Here in Kansas, it's time to be thinking about summer patch in sites that have a history of this disease. For more information, you can check out this website:

It focuses on Kentucky bluegrass but information is relevant to other grasses as well.

Got Brown Ring Patch?

Well, if you have those bright yellow rings on annual or rough bluegrass and its between 65 and 90 degrees F, there's a good chance you have some brown ring patch (aka Waitea patch) brewing this spring.

Like John mentioned earlier this week, symptoms can look a lot like yellow patch or even the early stages of southern blight or fairy ring. A definitive diagnosis should be made - but bright yellow rings with a slightly green ring inside of that are good symptoms of brown ring patch on Poa greens. Here's a classic photo of the disease taken a while ago by Pat Gradoville at Palos Verdes Golf Club.

There's a downloadable PDF on my website that covers the symptoms, biology and control

In a nutshell - at least two fungicide applications are often needed for complete control. Some fungicides like Headway or Endorse appear to give quick knock down of the disease, while others like Trinity or ProStar apear to take longer to act but can give very good residual control.

Other than that - rapid blight continues to hit salt affected Poa greens in the west (more on that next week) and spring dead spot symptoms are popping up on bermudagrass as we are in full transition to warm season turf growing conditions here and some guys are ony now seeing how thin (or dead) their bermuda bases are. Check out Lane's timely post on SDS for tips and tricks for dealing with SDS recovery.

Gearing Up for Another Growing Season!

Spring has sprung in the Midwest! The trees are blooming and budding, the flowers are emerging, and the grass is finally growing. This winter was pretty harsh, with many places receiving significant amounts of snow fall. Consequently, snow mold was quite severe this year. However, most are on the road to recovery from any snow mold damage. Another major issue was ice damage and desiccation. Many golf course superintendents through out the Upper Midwest claim the damage from ice and desiccation was as bad as they've ever seen. So before implementing a plan of action to start the road to recovery, you need to determine if the area will come back. To do this, take a cup cutter plug from the damaged area and place them in a window. Keep them moist and MAKE sure the window ledge is not directly above or below a heat vent. The drastic change temperature can cause shock that can kill the plants. Monitor growth from the plugs for two weeks and if green tissue has not emerged by then, the area will likely need to be repaired.

Now is also the time of year for preventative applications targeting fairy ring and take-all patch. If you are not familiar with preventative fairy ring applications, Lane Tredway's group at NC State is finding that two applications of Bayleton at the low label rate effectively limits fairy ring development throughout the summer. Initiate the first application when 5-day average soil temperatures are between 55 and 65 F, then follow-up with the second application 28 days later. All applications should be irrigated in with 1/4 inch of water immediately after application. Wetting agents should be applied on a regular basis during the summer, but NOT tank-mixed with the preventative applications.

Spring Dead Spot: What can I do now?

Spring has sprung in the southeastern US, and severe cases of spring dead spot have been reported throughout the region. The relatively severe winter is likely to blame, as cold temperatures tend to bring out spring dead spot symptoms.

The frustrating thing about spring dead spot is that the damage is done and the disease cannot be controlled once the symptoms appear. However, there are several things that can be done NOW in preparation for next year:

1. Consider converting severely affected areas to a cold-tolerant bermudagrass variety. Varieties of bermudagrass that have been bred for cold-tolerance, like Patriot, Yukon, and Tifsport, are affected by spring dead spot less severely. They still get the disease, but patches are generally smaller and recovery is quicker. This simple solution can save a lot of time and money in the long term.

2. Map severely affected areas for fall fungicide applications. Spring dead spot fungicides, like Rubigan, are very expensive. You can save a lot of money and avoid unnecessary fungicide use by only treating the affected areas.

3. Avoid the use of DNA herbicides for annual grass control. Some crabgrass herbicides reduce bermudagrass root growth and can slow recovery from spring dead spot. Use a pre-emergence herbicide like oxadiazon, which does not have this effect.

4. Aerify and/or spike severely affected areas every two weeks. Breaking up the layer of dead turf and thatch will help the bermudagrass to spread into the patch more quickly.

5. Choose your nitrogen carefully. The type of nitrogen you apply can have a major effect on spring dead spot development. We have traditionally recommended ammonium sulfate to suppress spring dead spot, but our recent research is providing some interesting results. After 4 years of applications, ammonium sulfate is only suppressing spring dead spot caused by Ophiosphaerella herpotricha and is having NO EFFECT on O. korrae. Calcium nitrate, on the other hand, is doing an excellent job of controlling spring dead spot caused by O. korrae, but is having no effect on O. herpotricha. Stay tuned for updates on this research.

Brown Ring Patch or Yellow Patch?

Disease activity is relatively slow at this point, but there are some reasons to believe that this will change soon. So far, several cases of brown ring patch and yellow patch (i.e., cool temperature brown patch) have been identified from Pennsylvania to parts of New England. A quick way to distinguish between these two diseases is to incubate a cup-cutter plug in a tuperware container overnight. If mycelium is present in the morning, you are likely dealing with brown ring patch as yellow patch does not produce much visible mycelium.

Main areas of interest throughout the region have focused on annual bluegrass seedhead suppression and the application of early season fungicides for the control of dollar spot or fairy ring. In situations where chronic disease activity occurs, these early season fungicide applications have been shown to reduce the severity of each disease later in the year.

If you are in the Northeast and experiencing other disease problems, feel free to let us know in the comments section.

patch-a-rama in Kansas

Hello from Kansas

The warm-season grasses are greening up. Spring rains and temps in the 60's and 70's are triggering the development of large patch in zoysiagrass (see photo). I have not seen or heard of symptoms of spring dead spot yet in bermudagrass but I'm sure that will be coming soon.

As for the cool-season grasses, a superintendent in south central KS reported some yellow patch (cool-season brown patch) in the putting greens. Late April is fairly late, but with our unusually cool, wet weather I'm not surprised that this disease has popped up. Another person reported some powdery mildew on tall fescue in the Kansas City area.
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