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Month: April 2015

Top 10 (okay, 9) questions about pine tip blight

(by Megan Kennelly, K-State Plant Pathology)

tip-blite
The classic symptom of tip blight is stunting and browning of new shoots and needles
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The 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
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).

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Tip blight can affect older wood along with the newest shoot tips. This photo shows both.
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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
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:

http://www.ksre.ksu.edu/bookstore/pubs/l722.pdf

 

9) What about injections?

Fungicide injections have been studied, but so far results have been inconsistent/ineffective and injections are not recommended at this time.

Got more questions? Feel free to email me at kennelly@ksu.edu

 

 

 

 

Best management practices for turfgrass anthracnose

Here is a sight that no superintendent wants to find on their course.These photos are from July/August of recent years.

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Courtesy Dr. Jared Hoyle
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Courtesy Dr. Jared Hoyle

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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.

http://turf.rutgers.edu/research/bmpsanthracnose2014.pdf

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.

Anthracnose fungal structures on turf
Anthracnose fungal structures on turf

anthracnose-setae-microscope setae

 

Diagnosing Turfgrass Issues

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Mystery Spot in Home Lawn
Mystery Spot in Home Lawn

Last year I wrote a post about some of the things I have learned while I have been in KS.  One thing was how hard it is to grow turfgrass in the north-western part of the transition zone.  And because it is hard to grow turfgrass here it is also hard to diagnose problems when they occur in our turfgrass systems.

So before we start talking about diagnosing turfgrass problems lets talk about how we are diagnosed when we are sick.  So one day you wake up and you don’t feel good.  You know your throat hurts, you have a fever so you go to the doctor.  While at the doctor’s office the doctor asks you questions like what hurts?, when did you start feeling bad?, have you taken any medicine?, etc.  So the doctor asks you questions to figure out what is wrong, Right? So you don’t just show up, sit down, and then say fix me. It is a process that you have to go through.

But after all the questions the doctor will prescribe you something to help you feel better. Maybe drink more fluids, get some rest, take some medicine, or all sorts of other remedies.  So you go home and start doing what the doctor tells you.  In about three days you still feel bad.  So you go back to the doctor and start it all over again.  And again you get your marching orders on how to feel better.  This time it worked and you are better.

That’s how we have to approach issues when they occur in turfgrass.  So many times I get a fuzzy picture and the question, “Why is my grass dead? Fix it!”  This is just like showing up at the doctor and saying “Fix me”.  So to properly diagnose a turfgrass issue some basic information is needed.

  1. What type of turfgrass do you have?
  2. What type of soil do you have?
  3. Is it a weed, disease, insect, or other issue?
  4. When did you first see what was going on? What time of year? How long has it been going on?
  5. Do you or someone else take care of the turfgrass? If someone else what do they do to the turf?
  6. What chemical or cultural practices have recently been conducted?
  7. What type of pattern is the damage? (uniform or random)
  8. Any other information?

I would recommend to have as much of the information as possible if you are really trying to figure out what is going on.  This way you can diagnose the issue quicker instead of having to go back and forth to finally get all the information for a proper diagnosis. That’s like having to go back to the doctor because the first diagnosis was incorrect because the doctor didn’t know all of the information.

Lastly, many times when you are gathering all this information, you end up solving the problem yourself!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page http://www.facebook.com/KSUTurf

 

 

You still have time! Preemergent Herbicides

(By Jared Hoyle, KSU Turfgrass Extension Specialist)

Pre-emergent (PRE) herbicides prevent summer annual weed (For Example, crabgrass, goosegrass, annual sedges, and spurge) seeds from developing into mature plants.  The reason we use PRE herbicides for summer annual weed control is because these summer annuals come back every year from seeds.  So if we can stop the seed from growing then we don’t have to deal with the weeds later in the season.

For all that don’t know how a PRE herbicide works here is a very short explanation.  They do not keep the seed from germinating but kill the young germinating plant.  With few exceptions they have no effect on existing plants, so they must be applied before germination.

But like in everything in life there is an exception.  Dithiopyr can kill crabgrass as long as it is young (two- to three-leaf stage, see photo below of three leaf crabgrass) and still have some residual for continued PRE activity. It doesn’t last as long as some of the other PRE herbicides but there is flexibility if you miss your window of opportunity to apply.

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So when do I put out the PRE application for summer annual weed control? Well, it depends on many things.  What summer annuals you have? Where are you located in Kansas?  Many times turfgrass managers center their PRE applications around crabgrass germination.  Crabgrass typically begins to germinate around May 1 or a little later in KS. April 15 is a good target date for applying a PRE because it gives active ingredients time to evenly disperse in the soil before crabgrass germination starts. The April 15 target works well for most of the state, but for southeast Kansas April 1 is more appropriate, and for northwest Kansas May 1 is best.  Additionally, weather varies from one spring to the next, and with it the timing of crabgrass germination. Some turfgrass managers base their PRE application around the bloom of the Redbuds but other ways can be used as well.  Crabgrass germinates when the soil at approximately 1 cm deep reaches 55° F.  So watch your soil temperatures to see when the soil consistently reaches 55° F. Here is a great website that will give you soil temperatures for your area.

http://mesonet.k-state.edu/weather/historical/

PRE herbicides do not last forever once applied to the soil. Microorganisms and natural processes begin to gradually break them down soon after they are applied. If some products are applied too early, they may have lost much of their strength by the time they are needed.  Additionally, PRE herbicides have different half-life, Koc, water solubility, and vapor pressure. This can determine how fast microbial, chemical and physical decay occurs along with infiltration, volatilization, leaching, and run-off.

Slide6

Therefore, not all PRE herbicides are created equal.   Here is a list of PRE herbicides, the weeds they target and some concerns that you might want to know before applying.

Active Ingredient Weeds Controlled Concerns or Comments
benefin summer annual grasses, annual bluegrass, some-small seeded broadleaves Do not use on golf course greens.
prodiamine summer annual grasses, annual bluegrass, henbit, chickweed, spurge, some-small seeded broadleaves Only apply to well established turfgrass.
bensulide annual grasses, some broad-leaves Do not use on putting greens composed of  > 50% Poa annua.
florasulam broadleaves, dandelion, prickly lettuce, clover Packaged with Dimension 2EW, florasulam great cool temperature activity, Prevents flowering in some broadleaves (dandelions).
dithiopyr summer annual grasses, annual bluegrass, yellow-woodsorrel, some small-seeded broadleaves PRE and early post-emergence activity on crabgrass.
isoxaben broadleaves such as chickweed, henbit, spurge, plantain, others Tank-mix with a grass herbicide for broader spectrum.
pronamide annual bluegrass, perennial ryegrass, other grassy & broadleaf weeds. Do not use on cool-season turf. Restricted use pesticide.
pendimethalin summer annual grasses, annual bluegrass, yellow-woodsorrel, some small-seeded broadleaves Not recommended for turf severely thinned due to winter stress.  Split applications can be made for extended control.
metolachlor annual bluegrass, crabgrass, sedges Do not use on cool-season turf.
simazine summer annual grasses, annual bluegrass, henbit, chickweed, spurge, some-small seeded broadleaves Do not use on cool-season turf.
ethofumesate annual bluegrass, annual grasses, some annual broadleaves See label for reducing annual bluegrass in cool-season turf.
oxadiazon summer annual grasses includinggoosegrass, annual bluegrass, some-small seeded broadleaves Ronstar G and Oxadiazon 2G are only formulations labeled for use on cool-season turf.
indaziflam annual grassy and broadleaf weeds in turf Do not use on cool-season turf.
oryzalin summer annual grasses, annual bluegrass, some-small seeded broadleaves Do not use on cool-season turf except tall fescue. 
dimethenamid bittercress, crabgrass, goosegrass, purslane, sedges, spurge On golf courses: Can be used on cool- and warm-season.  Other turf areas: Warm-season only.
siduron crabgrass, bermudagrass (suppression) Does not control goosegrass or annual bluegrass.

Information in this table was acquired from “Turfgrass Weed Control for Professionals” by A. Patton and D. Weisenberger, Purdue University. For more information about purchasing this publication ($12.00) for complete information see;

https://mdc.itap.purdue.edu/item.asp?Item_Number=AY-336#.VTENo94aj8s

For a digital copy (only $10.00);

https://mdc.itap.purdue.edu/item.asp?Item_Number=AY-336-W#.VTENy94aj8s

***There are many combination PRE herbicides that combine these active ingredients with each other and with other POST-emergent herbicides***

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

New Tall Fescue Publication Now Online!

(by Jared Hoyle; KSU Turfgrass Research and Extension)

The new Tall Fescue Extension Publication is now online!  You can get it under the publications tab at:

www.ksu.edu/turf

or directly at this link!

http://www.ksre.ksu.edu/bookstore/pubs/mf736.pdf

TF

 

 

Reeves and Alderman Place 2nd & 3rd in KSU Research Forum!

(By Jared Hoyle; KSU Turfgrass Research and Extension)

ImageWe would like to congratulate KSU Turfgrass Graduate Students, Jake Reeves and Evan Alderman for placing 2nd and 3rd in the K-State Graduate Research Forum Competition.  Jake Reeves placed 2nd in the Agriculture Poster Session and Evan Alderman placed 3rd in the Agriculture Oral Session.

Yesterday KSU Turfgrass Graduate Students, Ross Braun, Jake Reeves and Evan Alderman participate in the the 2015 K-State Research Forum.  Sponsored by The Graduate Student Council, KSU Graduate School, Offices of the President and Provost and Sigma Xi, the K-State Research Forum allows all graduate students across the university to compete in oral and poster presentation competitions about research they are conducting during their graduate career. The titles listed below represented the turfgrass graduate students that participated in the forum.

ENHANCING WINTER AESTHETICS OF ZOYSIAGRASS WITH COLORANTS     Ross Braun, Jack Fry, Megan Kennelly, Dale Bremer, and Jason Griffin

BERMUDAGRASS CONTROL WITH GLYPHOSATE, FLUAZIFOP, AND MESOTRIONE FOR SPRING RENOVATION                                                            Jacob A. Reeves, Jared A. Hoyle, and Cole S. Thompson

INFLUENCE OF NITROGEN FERTILIZER SOURCE AND RATE ON BUFFALOGRASS DIVOT RECOVERY                                                                                        Evan J. Alderman, Jared A. Hoyle, Jack D. Fry, and Steve J. Keeley

Job well done to all the participants in the K-State Graduate Research Forum!

The Art of Knowing Your Seed Label

(By Evan Alderman, KSU Turfgrass MS Student; Ross Braun, KSU Turfgrass PhD Student; and Jared Hoyle, KSU Turfgrass Research and Extension)

Do you enjoy having a nice green lawn, but didn’t have time to get your fall seeding done? Don’t fret, there is still time. Although the optimal time of year to seed cool season grass species is during the fall months, there is still time for you to get a great looking lawn for this summer. Now before you go to your local garden supply store and pick up some seed, there are several things you should take into account before making your purchase. The art of knowing your seed label begins now.

Turfgrass Species and Cultivar

seedSo you walk into your local garden supply store and you look at all of your options for potential seed you can use and you say to yourself “I really want a lush green lawn fast”. So you pick up a bag that says something along the lines of “quick establishment”, since that is what you want. Although this bag of seed sounds like a great option, you probably should check out the seed label before making this purchase. In the image is a picture of a seed bag with those claims. As you can see this bag contains 90.50% annual ryegrass (Lolium multiflorum) and only 5.97% perennial ryegrass (Lolium perenne). Now as a turfgrass scientist I can assure you that you may have a great looking lawn temporarily, but annual ryegrass should not be a long term solution. Which is why Rule #1 for the art of knowing your seed label is know what turfgrass species performs best in your area. For much of the state of Kansas, tall fescue (Lolium arundinacea) is the predominant species in most home lawns. Tall fescue is able to handle most of the drought conditions that Kansas likely endures.

Rule #2 for the art of knowing your seed labels is also knowing which species cultivars grow best in your area of the country. One of the best options for knowing which turfgrass cultivars perform best in your area is the National Turfgrass Evaluation Program (www.ntep.org). On their website, there is data available for homeowners to look at from many different university studies involving different turfgrass species and cultivars. This information will help you make an informed decision on what turfgrass species and cultivar will work best for you, this is a step in the right direction for achieving that lush green lawn you are wanting.

Other Seed Label Information

Although some of the most important information on the seed label is the turfgrass species and variety, there are several other pieces of information on the label that can be helpful. Rule #3, look at the percent germination for all turfgrass species on the seed label. Just because that type of seed is on the label doesn’t mean all of it will germinate. Thus it is important to look at the germination rate, and chose a bag of seed that has a high germination percentage. Rule #4, although the bag of turf seed you are going to by mostly contains grass seed, bags of seed can also can weed seed. It is very important to look at the percentage of weed seed in your bag of seed, if that percentage is high, I would probably pass on that bag and look for another one with a lower percent of weed seed. If a seed label has 0.5% weed seed then that equals approximately 12 to 16 weeds being planted per square foot. A seed label with <0.01 weed seed is good but 0% is best. This also applies to the “other crop” section of the label. Lastly, Rule #5, consider the seed testing date on the seed label. As with anything, turfgrass seed can get old, this will highly effect the germination percentage from that bag of seed. It is recommended to use newer seed and avoid anything over one year past the testing date.

Utilizing these five rules will help you make an informed decision for planting a lush green lawn this spring.

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf