We are at the junction/transition of spring to summer. Large patch is still raging in the zoysiagrass. Dollar spot is active in bentgrass and other susceptible turfgrasses, especially in susceptible varieties. In addition, we’ve had some nights with lows in the upper 60’s or low 70’s, and that can mean brown patch activity. It’s a busy time for diseases. As one of my colleagues said, “It’s a fungusy sort of year here in Kansas.”
With all the rain, it’s been hard to keep up with the mowing. We are feeling it at Rocky Ford, with Cliff and the students busy mowing whenever they can sneak it in. And, it’s hard to spray fungicides when it rains every other day. I put out a trial this past Monday since it was the only day that looked clear. Good thing it was not on the agenda for yesterday, when we had 3 thunderstorms in the same day!
Large patch is still rolling in the zoysia:
Dollar spot is active:
Brown patch might not be far behind:
With all the wet, saturated soils there could by Pythium root rot as well:
(Pythium spores stained pink in the microscope).
As a final note, I’ve gotten some questions and photos recently about algae.
Like other weeds, algae likes to take advantage of thinned out turf. Saturated soils and poor root growth can thin out the turf, and algae loves wet conditions. If you didn’t know where your drainage problems were, algal growth can point the way. There are some fungicides labeled for algae, but addressing the underlying site issues is key.
For a list of fungicides for algae, check HERE and go to page 7.
With all the recent rain, large patch in zoysiagrass is definitely active. I’ve already posted some info, here are just some more photos to show symptoms at Rocky Ford. The top two are at fairway height, and the bottom shows the disease at two mowing heights.
I have a quick story to share that is kind of funny, and it is disease-related in an indirect way.
At my house, we had a Scot’s pine that we figured would eventually get pine wilt. Last year, it got the disease, and like good citizens we took it down and destroyed the wood. (That is the disease part of the story).
This left a bare spot in the lawn, so we planted some seed. A day or two after that, Manhattan got some drenching rains and flooding. Our seeds (and the soil) moved around in all the water. Some of it moved down the slope all the way into the flower bed. The rest ended up pooled/clumped. If you click on the photos below to zoom you will see it better.
It’s a little hard to tell in the photo, but the ground slopes from upper right to lower left. Our grass seeds, and some of the soil itself, got washed down into the flower bed where it is now growing nicely.
So, we decided to try an experiment and transplant some of the clumps from the flower bed back up into the bare patches.
Iris Leaf Spotis active and has been favored by the cool, wet weather conditions we are currently experiencing across much of Kansas. The spots are typically found on the leaves but can occur on the stalk and buds of the developing flower. The spots are dark with a reddish border and will appear water soaked followed by yellowing of the surrounding tissue.
The edge of the spot has a water-soaked appearance. (Image by Megan Kennelly). Click to zoom.
The leaf spots develop a yellow border. Image by Bethany Grabow. Click to zoom.
As the disease progresses, the tips of the infected leaves will appear scorched. The disease will not kill the plant however it can reduce the plant vigor over time.
Scorching or dieback of infected leaves. (Click to zoom)
How can you protect your irises? The first step is to practice good sanitation by removing all the dead leaves prior to spring green up. The fungus that causes iris leaf spot overwinters on the dead leaves from the previous year, and removing those leaves will break the life cycle.
If you have a history of severe iris leaf spot and yearly sanitation alone is not effective, fungicides are available. Fungicides can be sprayed every 10 days for 4 to 6 weeks starting when new leaves emerge in spring. For more information on fungicide products and application for iris leaf spot go to http://www.hfrr.ksu.edu/doc1645.ashx. Be sure to follow the instructions on the fungicide label.
If you see these diseases, you may be eager to try something this spring, but the best time for fungicides is in the fall.
At KSU we’ve had good results for large patch with 1-2 fall applications. That is, fall applications have carried all the way through the following spring. Spring applications can reduce the disease but are not as effective as fall applications. There is ongoing research in the turf research community to try to optimize application timing, though, including with our colleague Dr. Lee Miller at U of Missouri.
With spring dead spot, application success has been more spotty here, but again fall has proven more effective. However, sometimes fall applications just don’t work. Cultural practices are critical, and the link above shares some great tips. Just page through to the spring dead spot section.
One very useful thing to do this spring is to take photos and map the diseased areas so that you can target those areas this fall. With large patch, I know several superintendents who only spray the known “hot spots” instead of entire fairways, with good success.
What’s going on here? First – what grass is it? This is bermudagrass, one of our warm-season grasses. When we have cold snaps, these grasses can take on a purple-red tinge. The chlorophyll is damaged and the anthocyanins become visible. If you look across a whole field, the red-purple can also have a brown-ish appearance, and that makes people wonder about diseases. But, if you look closer, you’ll see that it is purple. The turf grows out of it once temperatures are warmer.
In many parts of the state our overnight lows dropped into the 30’s last week, so the timing fits the symptoms – that is another important piece.
It’s not quite Wildcat purple. If we could do that, we’d have a nice patent on our hands and we wouldn’t have to worry about our research budgets anymore.
Here are some photos from a couple of years ago showing similar symptoms after a cold snap in early May. In the “long view” shot you can see how it can have a brownish cast, which can cause concern.
The classic symptom of tip blight is stunting and browning of new shoots and needlesThe classic symptom of tip blight is stunting and browning of new shoots and needles
Pine tip blight is a fungal disease that can affect Austrian, Scots, ponderosa, and mugo pines. The disease is most severe on mature trees (20 years or older). Repeated infections over several years can kill large sections of trees or entire trees. Here are some Frequently-Asked-Questions about tip blight.
1) What is the pathogen?
Tip blight is caused by a fungus that has been called both Sphaeropsis and Diplodia over the years. The current name is Diplodia. Don’t let the name changes trouble you. The most important consideration is to recognize the disease, and to be able to distinguish it from other pine problems such as Dothistroma needle blight or pine wilt. To learn more how to compare/contrast those diseases, you can check out this page: http://www.ksre.ksu.edu/bookstore/pubs/l722.pdf
2) When does pine tip blight occur?
Tip blight is a spring disease. The fungus survives the winter in previously-infected tissue. Then, during spring rains, the fungal spores splash around and infect the newly developing pine shoots (candles) just as they start to grow (usually in mid-late April).
Pine tip blight spores in the microscope. Spores are spread during spring rains, and they infect new shoots.
3) What are the symptoms of pine tip blight?
The symptoms become obvious in late May or early June when the infected shoots and needles are not growing right. The shoots are stunted, and the emerging needles are stunted and brown – see the photos at the top of this post. Small, sticky resin droplets often form on the infected needles. The damage usually starts in the lower branches and works its way up over several years. In trees that have been repeatedly infected for many years, damage is distributed throughout the crown.
In addition to infecting the newest growth, the fungus can invade older tissues when trees are highly stressed or if they are wounded (by hail, storm damage, etc).
Tip blight can affect older wood along with the newest shoot tips. This photo shows both.In this tree, the tip blight fungus has invaded some older parts of the wood, resulting in major tree damage.
Interestingly, white pines are not susceptible to the tip blight phase, but they are susceptible to this “canker form” of the disease if they are wounded.
In late summer or fall, tiny black spore-producing structures (called pycnidia) are formed on the scales of 2-year-old cones — it looks like black pepper has been shaken onto the undersides of the cones.
Tip blight on cones. Click to zoom, and you’ll see black specks. Those are the fungal spore-producing bodies.
Tip blight can be confused with winter damage or infestation by the pine tip moth. However, winter damage usually causes shoot or needle death before the new needles emerge in the spring, and it is sometimes restricted to one side of the tree (the side facing the prevailing wind). Unlike tip blight, the tip moth causes a hollowed-out area in the tip/bud area, and the larvae are sometimes present. Plus, tip moth is more common in young trees. The timing and pattern of symptoms, and the age of the tree, can help you with the diagnosis.
In extreme cases tip blight can be confused with pine wilt. To avoid confusion, look carefully at the symptoms and compare them to the descriptions and photos here and in other resources. Pines can be infected with both diseases simultaneously. If there is any doubt, bring a sample to your local K-State Research and Extension office to be forwarded to the K-State diagnostic lab.
Managing tip blight:
4) Does pruning help?
Removal of dead branches can improve the appearance of diseased trees but will not prevent infection. Many of the spores are produced on cones that remain attached to the tree. In addition, tissues that look healthy can secretly harbor the tip blight fungus. That is, there are “hidden infections” that we can’t even see. Usually, pruning for tip blight means pruning off lower branches first, since they tend to be the first to become infected. Then the pruning task moves up the tree as the disease progresses over the years. If a tree reaches a point where it is no longer pleasing or functional for the site, “one-cut pruning” (ie, tree removal) might be the best possibility.
5) What other tree care should I provide?
Trees should be adequately (not excessively!) watered to maintain tree vigor. This will help a tree fight off tip blight on its own. When a tree is drought stressed it has less energy and resources to put into defenses against pathogens.
6) Should I use a fungicide?
This is a tricky question. The trouble is, unlike smaller plants like wheat, tomatoes, or soybeans, there aren’t many studies out there to tell us about tip blight “thresholds.” As a general rule, if a tree has at least 30-50% of branches infected, the fungus is pretty well entrenched and it will be difficult for fungicides to really knock the disease down. And, if there is a lot of “canker” type infection in older wood, it is hard for fungicides to work. If a smaller portion of the canopy is affected, and it is mostly the “tip-blight” phase, fungicides are more likely to be successful over time. Finally, consider the aesthetics and site-enhancing value of the tree. In trees where the disease is caught early, and fungicides are used at the right time each year for multiple years, the disease can be managed successfully and it might be worth the investment.
7) Okay, so what is the right time for fungicides?
The critical time for fungicides is when the new shoots are expanding in the spring. If fungicides are applied at this time, new disease can be prevented. It is not a one-shot-deal, however, and not even a two-shot-deal. Fungicides will likely be needed each year to protect new annual growth. Each year, the first application should be made when new shoots start to elongate, which is usually around the third week of April. The tree should be sprayed again 10 to 14 days later, and possibly again 10 to 14 days after that if it is a wet year and the site has a history of disease. The timing should be adjusted slightly depending on host development in the spring, since every year is different. Spraying after this critical time will not be effective, because infection has already occurred and cannot be “cured.” Once you see symptoms it is too late.
8) What should I spray, and how should I spray it?
Several fungicides are labeled for pine tip blight. Thorough coverage is essential. A high-pressure sprayer may be needed to deliver the fungicide to the tops of tall trees. Homeowners should consider using a professional tree care service, especially for large trees where getting good coverage is difficult. Some fungicides (active ingredients) are listed on the last page here:
Here is a sight that no superintendent wants to find on their course.These photos are from July/August of recent years.
Courtesy Dr. Jared HoyleCourtesy Dr. Jared Hoyle
What is this problem? It’s hard to tell just based on photos, but after follow-up testing in the lab, we determined this is anthracnose, an important fungal disease in putting greens.
How does nitrogen (timing and amount) affect anthracnose?
Does rolling increase anthracnose? What about foot traffic?
How does irrigation impact anthracnose – should I run the turf wet or dry to prevent it?
Over the past few years, a team of turfgrass researchers has been conducting experiments to answer these questions. The have developed a science-based list of best management practices (BMPs) for turfgrass anthracnose. Various researchers studied the effects of nitrogen, potassium, mowing, rolling, plant growth regulators (PGRs), irrigation, topdressing, aerification, foot traffic, and fungicides. Based on that work, they developed a set of recommendations.
Rather than copy all the text into this page, I’ll provide the link below to their BMPs (it’s 2.5 pages – detailed, but concise and easy to understand), then add a few comments and photos.
Here in Kansas, the samples of anthracnose that I have seen were usually associated with the “risk factors” identified in the BMP list – low mowing, keeping N low to keep things “lean and mean” before a tournament, poor drainage at the site, etc.
Okay – anthracnose is more likely during summer stress. Why am I talking about this NOW?
It’s important to keep the BMPs in mind all season long, not just when you are already into a stressful time of year. Managing the turf holistically, all-season long, will help reduce your risk of this disease. As you’ll see in the BMP’s, it’s mostly a set of good agronomic practices, too. There’s nothing on that list that is out-of-bounds with routine good agronomy. And, you don’t necessarily have to do EVERYTHING on the list but I’m sure you will find some practices that fit with you and your site and budget.
I’m so happy to share this great news. Our own Christy Dipman was selected as a recipient of the 2015 K-State University Support Staff Award of Excellence! The eligibility included:
Outstanding Achievement and Performance: (Consistently and substantially exceeds the expectations of the position, performing at a level above and beyond normal job requirements; has made important and significant contributions in their area; has furthered the mission of the unit, college, and/or university.)
Inspirations of Excellence in Others: (Consistently and substantially demonstrates an ability and willingness to work positively, respectfully, and effectively with others; has significantly improved customer service or has increased student satisfaction in their area; demonstrates ability and willingness to manage changes in work priorities, procedures, and organization.)
Initiative and Creativity: (Has significantly improved a work process or system, or has significantly increased the efficiency of an operation or department/unit; consistently seeks to improve the quality of work assigned; demonstrates efforts to expand work responsibilities.)
Anyone who knows Christy knows that she shines in all of these areas. Most of you who read this blog know Christy primarily from the turf world, but she is an excellent colleague for those of us who also work with other commodities as well.
I was the nominator and three colleagues were more than willing to write additional support letters. Here are some of the things I wrote in my nomination statement, and I could (and did) go on and on:
“With Christy, there’s no worry about checking in to see if something is getting done. By the time you think to ask, she’s ALREADY done it!”
“At the annual turfgrass conference in Topeka, Christy works the registration desk. She greets everyone with a smile and knows many of them by name. They all know her! The participants are very comfortable with her, and her presence, attitude, and respectful nature help set the tone for the entire conference.”
“She does all this with a very positive attitude. I don’t recall her ever speaking negatively of anyone within KSRE extension or out among the stakeholders. This positivity radiates out into the whole extension team. Christy is one of the most positive individuals I have ever worked with.”
Congrats Christy! (I’m sure if you are reading this, you are blushing and feeling modest, but you are the BEST!”
