I have had a number of calls lately on white clover.There seems to be more of it this year than people have seen for awhile.That is not your imagination.Clover loves wet weather, particularly early in the summer.In 1993, the wettest year on record for Iowa, clover took over many golf course fairways, lawns and sports fields in Iowa.
Below are a couple of pictures from a driving range in central Iowa taken on the 28th of June, 2010.This is typical of what we are seeing this summer.
What can be done?Clover is surprisingly tolerant of 2,4-D, our old standby for broad leaf weed control.It is not uncommon for areas treated with 2,4-D alone to have the clover curl up, but then recover in a few weeks.
The best herbicides for clover control are those that contain MCPP, or one of the pyridine compounds:tyiclopyr, chlopyralid, and fluroxypyr.Of the three pyridines, triclopyr seems to be the best in my experience.You can find these compounds in several of the combination products for broadleaf weed control.Remember that any of the materials present a risk to dicotyledenous plants in the landscape such as trees and shrubs.They are also deadly to tomatoes and most flowering plants.
Ok, so I know that we usually write about topics relevant to turf, but the rain has stopped, the temperatures have broken, and sometimes it’s just nice to take a break and talk about something fun…like a great burger. Those of you who sat in on my technology talk at last year’s Iowa Turfgrass Conference already know about the Triple D app (Diners, Drive-ins, and Dives) and heard me wax poetic about my missed opportunity at experiencing the Cheesy Sacramento from Brewburgers.
For those that don’t know the story, I was in Omaha over Memorial Day Weekend 2009 with a stop scheduled at Brewburgers, only to find out the restaurant wasn’t open on Memorial Day. Well, I was back in Omaha this past weekend and had a successful rendezvous with the Cheesy Sacramento. The Cheesy Sacramento is a typical burger apart from being smothered with a mountain of cheese that forms a nifty “cheese skirt” thanks to a unique cooking technique. It took some doing, but I was able to work my way through all the cheese.
A video featuring Brewburgers and the making of the Cheesy Sacramento is below. We’ll be back tomorrow with actual turf related stuff.
The blog turns one today. Can you believe how fast the time has gone? Here’s a quick recap from our first year of blogging.
- 113 articles on a wide variety of subjects were posted to the blog during its first year. Special thanks to everyone that contributed by sending in an article. The blog really becomes more dynamic when we can post information directly from industry professionals.
- The blog had over 11,000 visits from over 4,000 different visitors. We had visits from every state, except Alaska (Does anybody know someone in Alaska that can visit the site for us?) Iowa and the six surrounding states accounted for about 80% of the visits. Also, a shout out to Des Moines, Muscatine, Cedar Rapids, Ft. Dodge, and Urbandale for logging the most hits within the state of Iowa.
- The average time spent on the site was 1 minute 7 seconds. I’m actually really happy about that. Our goal is to get timely, relevant information to you. We’re not trying to write novels here!
The entire goal of the blog was to get relevant information to you in a way convenient for you, and possibly have some fun while doing it. Continuing with that theme, we are launching an iaTURF Facebook page where you will be able to access information from the blog. You may have noticed the blue Facebook button at the top of the right hand column. This links directly to the iaTURF facebook page. Become of fan of the iaTURF Facebook page by clicking the “Like” button at the top of the page.
Moss control on creeping bentgrass greens has become an important topic in recent years as mowing heights have decreased. Superintendents in the Chicago area have been using standard baking soda as a selective control.
The following pictures are from Tim Christians, Supt. of Makray golf course. He is using 6 oz of baking soda per gallon of water and spot treating moss as it appears. He is getting good control in about 24 hours following application, with no damage to the bent. As is the case with any moss control, reapplications will likely be necessary.
I would recommend limited experiments with spot treating before adopting this practice, but it seems to be working and it is very inexpensive.
Summer officially began yesterday although it has felt like summer for some time now. The temperatures forecasted for this week should create ideal conditions for disease activity. Our research facility has a buffet of diseases right now. I have seen red thread, leaf spot, yellow tuft, fairy ring, dollar spot, and brown patch just in the past week. The high stress conditions could also spur on anthracnose. If you think you have anthracnose, look for the black colored fruiting bodies on the leaves of plant. The fruiting bodies, or acervuli, are best viewed using a hand lens or hand held macroscope. More information about identifying anthracnose and management of this disease can be found by clicking here.
A droughty month of May has given way to a wet and rainy June. Weather is the great equalizer in the turf business and this season has been a rollercoaster compared to the steady temperatures we experienced in 2009. Overall, our day and nighttime temperatures have been warmer this year compared to 2009 for the month of June. It was this same time last year that we experienced a warming trend that sent temperatures into the mid 90’s. But so far the biggest difference in weather has been the rainfall. Twenty days into June last year, Ames had received 1.95 inches of rain compared to the 6.36 inches of rain we have gotten this year.
Golf fans saw Irish golfer Graeme McDowell win the 110th U.S. Open on Sunday by shooting even par over four rounds at Pebble Beach. Coming into this tournament I had no idea who Graeme McDowell was but I quickly gained respect for him when listening to his post round interview. While reflecting on what he had just accomplished, and in amongst his numerous thank-yous, he took time to thank the maintenance staff for all their hard work and commented on the great condition of the course. Classy move Mr. McDowell, now off to Disney World you go!
If your lawn went from one of the best in the neighborhood to one that resembled a straw field seemingly overnight then we may have an answer for you. Ascochyta leaf blight causes a rapid straw to bleached appearance of the leaves primarily on Kentucky bluegrass and to a lesser extent on perennial ryegrass and tall fescue. Home owners want to know why this happened only to their lawn and not to the neighbors. This is the most wide spread outbreak of Ascochyta that I have seen in my 30 years of managing turf. The good news is that Ascochyta spp. primarily attack turfgrass leaves and lawns usually recover quickly.
The damaged lawns started showing up around the first of June and 15 days later I have already started to see some regrowth from lower shoots. Some of the more severely damaged areas may require 3 or 4 weeks of good growing conditions to fully recover. More information about Ascochyta Leaf Blight can be found from these links to the Colorado State University and University of Missouri fact sheets. Here are some answers to the questions you have been asking about this turf problem.
What caused the problem?
A fungus called Ascochyta leaf blight cause the rapid straw discoloration of turf leaves and it was instigated by dry hot and dry conditions.
Why did the problem seem to stop right on the property line and why is my lawn having the problem?
The problem started with the hot and windy conditions in the last week of May that caused heat and moisture stress on many lawns. Since lawns with less nitrogen and no previous irrigation are more tolerant of sudden drought and heat, these more hardy lawns (usually the lighter green and less attractive lawns) were less affected by Ascochyta leaf blight.
Should I change my lawn management practices or lawn care company?
It is unsettling that the best looking lawns suddenly become the worst looking lawns, but I wouldn’t pin the blame necessarily on yourself or your lawn care company. We see Ascochyta leaf blight every year on a very small scale and it is normally an insignificant disease that simply recovers and goes away on its own. If you are fertilizing with 2 to 4 lbs N/1000 sq.ft. per year then you are not using excessive nitrogen. If you feel your lawn is receiving too much nitrogen then apply 0.5 to 1.0 lbs N/1000 sq.ft. less in a year to determine if you are content with the appearance at a lower level of nitrogen. A more important factor is how you water the lawn.
It appeared to me that many lawns with automatic watering systems were damaged. Your goal should be to water about once a week to supply approximately one inch of water. Watering more often produces shallow rooting, lush plants, more disease spores, and an overall less drought tolerant plant. The problem is not having an automatic irrigation system; instead it is how you use it. Automatic systems are an efficient and simple way to water the lawn. It doesn’t mean that just because you invested in one that you need to run it often. Instead your goal should be to operate the system as infrequently as possible. Allow the lawn to dry between irrigations and show slight wilting in just a few spots before you initiate an irrigation cycle. This insures air in the rootzone and promotes deeper rooting and plant cells that are more tolerant of dry conditions and disease.
The two most damaged lawns that I visited had been frequently watering with their automatic irrigation system and then suddenly stop using it for repairs when the hot and dry conditions hit in late May. The frequent watering may have produced excessive Ascochyta inoculum that only caused infection with the onset of heat and drought stress.
Should I use a fungicide?
No, fungicides are not recommended. First it is impossible to predict when Ascochyta will damage turf. Ascochyta is almost always associated with heat or drought stress, but turf often recovers from both of these stresses when Ascochyta is not present. It would not be practical to treat preventatively for Ascochyta every time we have heat and drought stress. Applications of fungicide on lawns already damaged by Ascochyta are also not recommended because leaves already damaged by this foliar disease cannot be helped and the recovering green leaves are not infected. What should I expect from my damaged lawn and what should I do?
Really, you should do nothing drastic to the lawn. In most cases the lawn will recover in 3 to 4 weeks. Once the brown tips of the leaves have been pushed up and mowed off the new green leaves will make the lawn look more normal. The straw turf along with the thatch in some lawns created dead looking debris on the surface and many of you have asked about power raking, dethatching , and reseeding to remove the brown grass. It is a judgment call that you and your lawn care company can make based on the amount of actual damage in the lawn.
Most of the lawns I am seeing will recover with at least 80% green turf and for that reason I would do nothing except irrigate only enough to avoid severe wilting. Since we are heading into the hottest and most stressful part of the summer I would not add more stress to the lawn by dethatching during the summer; save your coring and dethatching operation for the fall.
Here are a few pictures from the 20 lawns I visited in Des Moines, Ankeny, and Ames.
Last October we posted an article on the blog which discussed the emerald ash borer, its current location, the destruction it causes, and how to plan for the future in the face of this destructive pest. Well, the day of reckoning to closer upon us.
Allamakee County is now under a quarantine to prevent the spread of the emerald ash borer, which kills ash trees, one of the most popular trees in Iowa. Allamakee is located in far northeastern Iowa along the borders with Wisconsin and Minnesota.
Iowa Agriculture Secretary Bill Northey on Monday issued the quarantine on firewood and ash products, including lumber and bark chips. They can't be moved unless a permit has been issued by the Iowa Department of Agriculture or the U.S. Department of Agriculture or have been treated to exterminate any pests.
The emerald ash borer was recently discovered on an island in the Mississippi River in Allamakee County. The adult beetles are relatively harmless, but the larvae drill into the trees. A full copy of the quarantine can be read here.
Last week I was touring a golf course with the Superintendent and we had a discussion about yellow spots on one of their putting greens. Yellow spots can be the result of a number of diseases and conditions. Poa annua contamination and yellow tuft were the first two possibilities that came to mind. Being able to correctly identify the problem is very valuable as the fungicides labeled for yellow tuft can be costly.
This particular green is grassed with the new, high-density bentgrass cultivars. Many of the new bentgrasses are genetically darker green compared to the older cultivars. As a result, any poa that is present is even more distinguishable within the canopy. This color difference can easily be misdiagnosed as a disease and could be the cause of the yellow spots.
Like most diseases, yellow tuft seems to be most prevalent in areas that are poorly drained, over-irrigated, or have excessive thatch. This green is rather flat and has relatively poor surface drainage. The weather so far during the month of June has provided plenty of moisture with many parts of the state receiving over 5 inches of rain.
I collected some samples of the affected turf for further inspection. I was able to detect a fair amount of poa within the samples. The poa could be contributing to the yellow appearance but might not be the sole cause as yellow tuft can occur on most turfgrass species although it is most common in creeping bentgrass or annual bluegrass. Digging a little deeper, I was able to find clusters of tillers originating from a single crown. This symptom is characteristic of yellow tuft and is the result of a plant hormone released by the disease pathogen.
In this case, even though poa was present in the canopy, the yellow spots were probably mainly the result of yellow tuft. With all the rain most parts of the state have received the conditions that would favor yellow tuft development are favorable. Cultural controls for yellow tuft include ensuring adequate surface and subsurface drainage. As far as chemical controls, the mefanoxam (Subdue Maxx) and fosetyl-Al (Signature) are the only fungicides currently labeled for yellow tuft.
The following is a post from Tim Christians, Supt. of Makray Golf Course in the Chicago area. It happened last week during a thunder storm. Lightning hit above an irrigation line (there was no head above ground at this location) and shattered the underground pipe. You can see pieces of plastic on top of the ground.
Last week I stumbled across something I have never seen before. The picture below shows a bentgrass/poa putting green with distinct lines spanning lengthwise across the green. I have observed dark green lines appear beneath the seams of covers shortly after removing the covers in the spring. The line in this picture is the result of a shift in grass species; the dark line is creeping bentgrass. It appears that the microclimate created directly beneath the seam of the cover allowed the bentgrass to outcompete the poa. More of these “lines” were visible on this green but not all greens on the course displayed this same response. I would be interested to know if anyone else has ever observed this before.
Green Bay Country Club is 16 years old. I have been working hard trying to keep the Poa annua out, or at least under control, since the course was built. I have used Prograss, Velocity, TGR, Cutless, and pre-emergence herbicides, etc. over the years. Nothing has ever convinced me to keep going on a program because of the poor results I always get.Half our fairways were originally seeded to Pennway creeping bentgrass and the second half to Providence creeping bentgrass. In 2009 we had approximately 5% Poa annua.
During the summer of 2009, I decided to get as aggressive as I have ever been. On May 22, 2009, I treated all of our fairways with a full rate of TGR 31-3-6. That is 32 oz/ac of Paclobutrazol and 0.85 lb. N/1000 ft2. That was the first time I ever applied that much TGR over all of our fairways.
In July, I started applying Velocity at various rates and at various frequencies. I wanted to incorporate all the different approaches I have read about, includingthe “quick reduction” and the “slow reduction” programs. I applied Velocity twice at a 6 oz/acre rate and 14 days apart on six fairways. I followed these applications with 2oz/acre Velocity, also on two week intervals.In total, I ended up with a few fairways. receiving 14oz/acre (6+6+2 oz), a few fairways getting 18oz/acre (6+6+2+2+2 oz), one fairwayjust got the two 6 oz. applications. Thirteenfairways received no Velocity.
One of my 18 oz/acre fairways also got a second application of TGR on Aug. 18th at full rate. This fairway received a total of 64oz/acre paclobutrazoland 18oz/acre Velocity. This fairway was treated with the highest rate of chemical of any fairway in the trial.
My observations in 2009:
1.There were several interesting color changes in the fairways. The Velocity turned the bentgrass a very lime green color, which is not a problem unless you skip an area. Then the color difference is obvious.
2.The Velocity treated fairways looked very droughty towards the end of summer. Kind of sick and worn out looking.
3.I did not observe any noticeable differences in Poa annua populationsbetweenany of the treatments in the fall of 2009.
In the spring of 2010, I was hoping to see some real differences in Poa annua infestation among the fairways.I waited until seed head formation before drawing any conclusions. The spring of 2010 has been a banner year for seedhead formation on the Poa annua.Unfortunately, I could see no difference in Poa annua infestation between the untreated fairways and any of the treated fairways.
The only place that I noticed any damage to Poa annua was on small areas of three of the greens. It took a month before I figured out what had caused this. While spreading TGR on our green collars last summer, I grabbed handfuls of the material from the spreader and hand sprinkled it directly on the small Poa patches in these three greens. I saw no ill effects last summer or fall, but this spring it was obvious something had been applied in these specific areas.
What are my plans during the 2010 season? I am going to spray 8 oz. paclobutrazol and 4 oz Primo on all our greens and fairways at three week intervals beginning the week of June 7th. I have already applied TGR 31-3-6 at half rate on all fairways.
I still am not convinced that any of this is worth the cost in labor and material. The Poa annuapopulation keeps growing. I am willing try just almost anything, but I am unwilling to waste money if it’s not working.
I would like to hear from other superintendents concerning their experience in controlling Poa annua.
I can be reached at:
mdavison@greenbaycc.org
or
920-339-4640
Or you can post your results on the blog by sending an e-mail to Nick Christians at
.jpg)
