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Category: Diseases

Homeowner Do-It-Yourself Lawn Calendar for Warm-Season Grass

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Last week I got a lot of good feed back on the Homeowner Do-It-Yourself Lawn Calendar for Cool-Season Grasses so I decided that it would be good to go ahead and get the warm-season lawn calendar out there for everyone that is manageing zoysiagrass, bermudagrass or buffalograss.

The following is a lawn calendar for zoysiagrass and bermudagrass. Buffalograss, also a warm-season grass, but we will cover that separate because the management of buffalograss is a little different then zoysiagrass and bermudagrass.

Zoysiagrass and Bermduagrass Lawn Calendar

March
Spot treat broadleaf weeds if necessary. Treat on a day that is 50 degrees F or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.

April
Apply crabgrass preventer between April 1 and April 15, or apply preventer when the eastern redbud is in full bloom. This year we are getting a little warmer sooner but remember this cold snap that we just had would have killed any crabgrass if it had germinated. If using a product with prodiamine (Barricade), apply two weeks earlier. Crabgrass preventers must be watered in before they will start to work.

May – August 15
Fertilize with 1 lb. of nitrogen per 1,000 square feet per application. Follow the recommendations on the bag. More applications will give a deeper green color, but will increase mowing and may lead to thatch buildup with zoysiagrass. Bermudagrass can also have problems with thatch buildup but thatch is less likely with Bermuda than zoysia. Bermudagrass – Use two to four applications. Zoysiagrass – Use one to two applications. Too much nitrogen leads to thatch buildup.

One Application: Apply in June.
Two Applications: Apply May and July.
Three Applications: Apply May, June, and early August.
Four Applications: Apply May, June, July, and early August.

Remember to look and see if you are using a quick release nitrogen source or a slow release nitrogen source.  If you use a quick release source then it is immediately available but only lasts a couple weeks.  Thats why you would have to make a couple of applications like it is listed above.  If you are going to use a slow release source it will tell you on the bag how long the product will last.  Therefore, you might not have to make as many applications.

So generally you want to use a total of 2 to 4lb. of nitrogen per 1,000 square feet per year for bermudagrass and 1 to 2 lb. of nitrogen per 1,000 square feet per year for zoysiagrass.

June
If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. June is a good time to core aerate a warm-season lawn. Core aeration will help alleviate compaction, increase the rate of water infiltration, improve soil air exchange and help control thatch.


Late-July through August
If you see grub damage, apply a grub killer. If Imidacloprid has been applied, this should not be necessary. Grub killers must be watered in immediately.

Late October
Spray for broadleaf weeds if they are a problem. Treat on a day that is at least 50 degrees F. Rain or irrigation within 24 hours reduces effectiveness. Use the rates listed on the label for all products mentioned.

 

Buffalograss Lawn Calendar

Buffalograss has become more popular in recent years due to its reputation as a low-maintenance grass. Buffalograss does require less water and fertilizer than our other turfgrasses but often has problems competing with weeds in eastern Kansas. Remember, buffalograss is a low-maintenance lawn and not a “No”-maintenance lawn.

Buffalograss is an open growing grass that will not shade the soil as well as most of our other turfgrasses. Weeds are often the result. A regular mowing schedule can reduce broadleaf weed problems as most broadleaves cannot survive consistent mowing. Those that do either have a rosette growing pattern (dandelions, shepherds purse) or are “creepers” (henbit, chickweed, spurge). Annual grasses such as crabgrass or foxtail can also be a problem. A good weed preventer (prodiamine, pendimethalin or dithiopyr) may be needed prevent problems.


March

Spot treat broadleaf weeds if necessary. The most important treatment for broadleaf weeds should be in late October to early November well after the buffalograss is dormant. Treatments are much more effective then than in the spring as the weeds are smaller and the weeds are sending energy, as well as the herbicide, to the roots. Treatments in March are to take care of any “escapes” missed in the fall spraying. Spray early enough in March that the buffalograss is still dormant. Look at the base of the plants to make sure there is no green. Treat on a day that is 50 degrees F or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.  Use a combination product such as Trimec, Weed-B-Gon or Weed-Out. Weed Free Zone is also good and will give quicker results under cool conditions.

April

Apply crabgrass preventer between April 1 and April 15, or apply preventer when the eastern redbud is in full bloom. If using a product with prodiamine (Barricade), apply two weeks earlier.  Crabgrass preventers must be watered in before they will work. Avoid using broadleaf herbicides as the buffalograss is greening up as injury can result. The buffalograss will not be killed but growth will slow making the buffalograss less competitive with weeds.

June

Fertilize with 1 lb. of nitrogen per 1,000 square feet during June. More applications will give a deeper green color, but can encourage weeds. If it is felt that a second application is needed, apply in July.

If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. Again, I would only treat if grubs have been a problem in the past. Note that the whole area may not need to be treated. The beetles that lay the eggs for the grubs are attracted to lights and moist soil and those areas are most likely to be infested.

Late-July through August

If you see grub damage, apply a grub killer. If imidacloprid has been applied or if grubs have not been a problem in the past, this should not be necessary. Grub killers must be watered in immediately.

Late October to Early November

Spray for broadleaf weeds if they are a problem. Look carefully as our winter annuals such as chickweed and henbit are small and easily overlooked. Use a product that contains 2,4-D as it increases effectiveness on dandelions. Treat on a day that is at least 50 degrees F. Rain or irrigation within 24 hours reduces effectiveness. Use the rates listed on the label for all products mentioned.

It is as simple as that!  Enjoy!

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

Homeowner Do-It-Yourself Lawn Calendar for Cool-Season Grasses

(By Jared Hoyle; KSU Turfgrass Research and Extension)

Where did winter go? Or was it even here?  Depending on where you lived in Kansas you could have had a cold winter, warm winter, or a mild winter… But now it is getting warm and quick.  So before we get left behind lets prepare your cool-season turf for the year.

Homeowner Do-It-Yourself Lawn Calendar for Cool-Season Grasses
The following suggestions are for cool-season grasses such as Kentucky bluegrass or tall fescue. Zoysiagrass, bermudagrass, and buffalograss are warm-season grasses and require a different maintenance regime.

March
Spot treat broadleaf weeds if necessary. Treat on a day that is 50 degrees or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.

DSCN0010April 
Apply crabgrass preventer (Or maybe even a little bit sooner this year) when redbud trees are in full bloom, usually in April. The preventer needs to be watered in before it will start to work. One-quarter inch of water will be enough to water in any of the products mentioned in this calendar.  Remember that a good, thick lawn is the best weed prevention and may be all that is needed.

May
Fertilize with a slow-release fertilizer if you water your lawn or if you receive enough rainfall that your turf normally doesn’t go drought-dormant during the summer. If there are broadleaf weeds, spot treat with a spray or use a fertilizer that includes a weed killer. Rain or irrigation within 24 hours of application will reduce effectiveness of the weed killer, but the fertilizer needs to be watered in. If you are using a product that has both fertilizer and weed killer, wait 24 hours after application before watering in.

June through Mid-July
Apply second round of crabgrass preventer by June 15 – unless you have used Dimension (dithiopyr) or Barricade (prodiamine) for the April application. These two products normally provide season-long control with a single application. Remember to water it in. If grubs have been a problem in the past, apply a product containing imidacloprid during the first half of July. This works to prevent grub damage. It must be watered in before it becomes active.

IMG_0563Late-July through August
If you see grub damage, apply a grub killer that contains Dylox. Imidacloprid is effective against young grubs and may not be effective on late instar grubs. The grub killer containing Dylox must be watered in within 24 hours or effectiveness drops.

September
Fertilize around Labor Day. This is the most important fertilization of the year. Water in the fertilizer.

November
Fertilize. This fertilizer is taken up by the roots but is not used until the following spring. Water in fertilizer. Spray for broadleaf weeds even if they are small. Broadleaf weeds are much easier to control in the fall than in the spring. Spray on a day that is at least 50 degrees. Rain or irrigate within 24 hours reduces effectiveness. Use label rates for all products!

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

Cut-and-burn those pine wilt infected trees

(Megan Kennelly)

Got pine wilt?

 

Get that tree outta there! Chop and burn or chip, making sure not to leave stumps. Get this done by April 1!

You know the drill. This disease has been killing our pines for decades. It is caused by a nematode that is spread by a beetle. The nematodes and beetles spend the winter in dead and dying trees. The beetles, loaded up with nematodes, start emerging in late April or early May and spread to new trees.

In the eastern 2/3 of the state, if you have a dead pine, there is a decent chance it has pine wilt. We have detected pine wilt a handful of times in western Kansas too.

Get those pine-wilt infected dead trees out of the landscape to help prevent spread to surrounding trees.

Pines have multiple problems though, and if you have any doubt you can work with your KSRE Extension agent to ship a sample up to KSU. For more information on pine diseases, check out our publication about Pine Diseases in Kansas

Iris leaf spot – spring cleaning to disrupt fungal life cycle

(Megan Kennelly, KSU Plant Pathology)

Irises are a popular plant, often grown in large groups. Iris leaf spot is a fungus that can cause mild spotting to severe dieback.The fungus spreads by spores that are dispersed in wet weather.

Red-brown spots with yellow halo:

A closer view – the black bumps are spore-producing structures:

 

Another close-up view of one spot:

Spots can coalesce to cover a large area

More significant dieback:

Where does that fungus spend the winter? In old infected leaves. Get those outta there to reduce your risk of infection in the new year. Clearing out old infected plant tissue breaks the life cycle.

More information about managing iris leaf spot is available in a recent article by Ward Upham in the KSU Horticulture News

 

Large patch goes trick or treating

Your zoysiagrass fairways and tees might have tried to dress up like a jack-o-lantern, turning itself orange for Halloween. The moderately cool, moist, foggy conditions are perfect for large patch development. We are seeing it in our inoculated plots at Rocky Ford but in lots of other places too. Normally zoysia is shutting down right now. Normally, one application in the fall usually does a great job. You can view a short podcast on large patch fungicide research at KSU. But when the disease is active into November? I’m not sure.

I’ve never seen zoysia this green in November. What a weird fall. Lots of strange things happening in plants. At home we are still harvesting peppers and tomatoes after dinner while comfortably wearing short sleeves, shorts, and sandals.

Anyway – what are you seeing out there? Did you treat in mid-September? If so, is it holding? If not, did you go back in? Let us know what is and isn’t working for you.

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Dollar spot keepin’ on keepin’ on

Dollar spot loves, dew, fog, and temperature 65-85 degrees and we have had those conditions lately.

As you think about your fungicide program, don’t forget about rotating among different mode-of-action groups. The Chemical Control of Turfgrass Diseases publication from Kentucky does a great job outlining those principles. Don’t forget to look at the active ingredient names and FRAC codes along with the trade name. You might think you are rotating, but you are not. You can read the general info on that page, and/or scroll to the info specific for dollar spot a few pages in.

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The Kentucky publication highlights some points about fungicide resistance. In a recent survey of isolates collected in Kansas, nearly all were fully resistant to thiophanate-methyl. That is, the fungus blew through it like it was not even there.

Rust activity in turfgrass

Over the past 1-2 weeks we’ve been seeing a lot of rust in lawn height turf. At Rocky Ford we are finding it in mainly perennial ryegrass but in little pockets in some newly-established zoysiagrass too.

img_3551 img_3550 img_3554 img_3553

The rust spores need wet leaf surfaces to infect, and we have definitely had some moist, dewy days and even some very foggy mornings. Though the fungus itself spreads best during wet weather, plants that have been stressed by drought are more susceptible. Nutrient-deficient turf is also more susceptible.

We have some information about rust in our publication Rust Diseases in Turfgrass (pdf).

Large patch in zoysiagrass

 

lp

(Megan Kennelly, KSU Plant Pathology)

 

If you manage zoysiagrass and have a history of large patch, you are undoubtedly already thinking about this disease, and maybe you just put out an application or are getting ready to do it soon.

There is some great info about large patch control at this link, starting on page 14.

http://www2.ca.uky.edu/agc/pubs/ppa/ppa1/ppa1.pdf

We’ve done quite a few trials at KSU over the years, and our results match pretty closely with the efficacy data shown at the above link. Regarding timing, we’ve had good control from most application timings in September.

Large patch tends to be in the same areas from one year to the next, so one option is to map out “hot spots” and focus on those.

Inoculation time!

In addition to large patch management, it is also time for large patch inoculations for research. Yup, most of you want to get rid of large patch. Here at KSU, we want MORE! I’m working with PhD student Mingying Xiang and Dr. Jack Fry in collaboration with Texas A&M, Purdue, University of Arkansas, and other universities to screen zoysiagrass breeding lines for disease resistance and agronomic traits as part of a USGA-funded project. We recently inoculated plots with the fungus that causes large patch disease. We cultured the fungus in the lab, grew it out on sterilized oats in glass jars, and then hauled our tailgate-of-death-and-destruction out to the field. To inoculate, we put the colonized oats just below the thatch. We might see some symptoms this fall, otherwise we definitely should see patches by spring. We will measure disease severity using digital images and other methods. We are hoping to find some breeding lines with good resistance. As we all know, starting with a resistant variety is the foundation of integrated pest & disease management.

 

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“My knees are getting tired from all this crawling”

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No, that is not our snack. Those are jars of the fungus growing on oats. Yum!

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We dig just barely down into the soil and place the oats, then put the flap of grass back down.

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Even after one (rainy) night, there was already new mycelium growing off the oats.

Turf health problems, above and below ground. And why your putting green soil should not look like tiramisu.

(Megan Kennelly, KSU Plant Pathology)

The soggy weather continues, and diseases are in full swing. Dewy, wet mornings lead to mycelial growth of the pathogens that cause dollar spot or foliar Pythium. These are mainly golf course concerns, but the diseases can occur at other sites.

Here is a sample that came into the lab, loaded with foliar Pythium:

IMG_3151

It is from a golf course fairway at a site that has received a lot of rain and some foggy mornings where everything is wet-wet-wet.

For management info on foliar Pythium, you can check these links:

http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf

(scroll through to the Pythium part on p.17)

http://extension.missouri.edu/p/IPM1029-17#Pythiumfoliarblight

 

Root health continues to be a problem, especially on putting greens. We’ve posted a lot of information this year about wet soils leading to physiological decline and triggering Pythium root rot in some cases (see links at bottom of this post). Putting greens with poor drainage, less-than-ideal construction, or a build-up of organic matter are particularly susceptible. Here are some putting green rootzones with a lot of organic matter build-up, visible as dark layers:

layers FullSizeRender

All those layers kind of look like tiramisu…mmm… yummy… getting distracted.

tiramisu

Unlike delicate layers of a tiramisu, layering in a putting green rootzone is NOT a delectable delight. Another complication of poor drainage is that it can make the turf more prone to anthracnose. I received a couple of samples in recent days with crown rot anthracnose. Both also had layering problems and root decline.

There is some information about anthracnose here:

http://www.bookstore.ksre.ksu.edu/pubs/EP147.pdf

and here is an excellent list of best management practices:

http://turf.rutgers.edu/research/bmpsanthracnose2015.pdf

Many of the practices to reduce anthracnose also promote overall turf health. That is, when you implement agronomic practices to promote good rooting you also reduce the risk of anthracnose and other problems. You may not be able to do ALL of the beneficial agronomic practices you would like, due to budgetary limits or lack of equipment or golfers’/greens committee opinions, but the more you can fit in, the better.

We posted on these topics earlier this year. If you want to go back and review, here are some links:

https://blogs.k-state.edu/turf/season-long-agronomic-practices-to-reduce-anthracnose-risk-in-putting-greens/

https://blogs.k-state.edu/turf/root-decline-it-aint-benign/

https://blogs.k-state.edu/turf/best-management-practices-for-turfgrass-anthracnose/

https://blogs.k-state.edu/turf/your-turf-is-trying-to-bike-up-a-mountain/

https://blogs.k-state.edu/turf/bentgrass-declining-its-from-western-europe-you-live-in-kansas-by-dr-fry/

 

 

Gray leaf spot in perennial ryegrass

(Megan Kennelly, KSU Plant Pathology)

If you manage perennial ryegrass you are probably well aware of the risks of gray leaf spot.I have not seen it, but I just got my first question about it for the year.

In this region the most common time for GLS symptoms to first appear is early to late August. In some years, epidemics can be severe. In other years, there is little to no GLS. The fungus is picky, with 82-90 degrees as its favorite temperature range. The fungus needs wet conditions as well. The fungus requires certain durations of leaf wetness at different temperatures. At that prime window of 82-90 degrees the infection can occur quickly.

Damage in a rye fairway, a few years ago.

gls-cropped

GLS spores in the microscope, a few years back.

spores

For more details and photos you can check out this page for general information:

http://extension.missouri.edu/p/IPM1029-11#Grayleafspot

And, here is some detailed fungicide information (scroll to page 13):

http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf