Tuesday, June 28, 2011

IMPRELIS UPDATE

Nick Christians
June 28, 2011

Information continues to come in daily on the Imprelis damage to trees. I received information on damage in the Cedar Rapids, IA area yesterday.

Below are some interesting links and some new pictures.

Link #1 is from the Penn State Extension service. Peter Landschoot is the author.
http://extension.psu.edu/greenindustry/giec/news/2011/some-observations-on-imprelis-injury-to-trees
The 2nd link is to a news broadcast from Indiana.

http://www.theindychannel.com/news/28238347/detail.html?taf=ind


Pine Damage from Chicago




Large tree in Kansas City.




Severely damaged tree in Wisconsin





Large tree showing damage clear to the top. This would indicate translocation from roots and not drift.


Monday, June 27, 2011

Diagnostic Update: One of our more serious fungal diseases arrived last week

This post comes to us from Dr. Derek Settle from the Chicago District Golf Association

Late last week, I heard word that a green was thought to be showing symptoms of anthracnose basal stem rot.  On Monday, in the rain, I made the visit.  Indeed the green did have the typical signs.  Poa annua was bright yellow whereas creeping bentgrass was fine.  Areas of the green that would tend to show wilt stress were most affected.  With a hand microscope that the Superintendent sues for field diagnosis, we both were able to see hair-like satae and black discolored stems.  The stems were easily detached when pulled because they had rotted.



The main cause was determined to be two-fold. 1) The weather.  Coincidentally, I had noted that low relative humidity values were striking on Monday and Tuesday (this was already unlike season 2010 which always seemed blanketed in high humidity).  The timing of the outbreak on Wednesday suggested the primary stressor was midday wilt.  2) Some DMI fungicides used for fairy ring prevention have little efficacy against anthracnose basal stem rot.  Our course of action was to reduce plant stress on affected greens.

Reduce wilt stress: monitor greens closely for midday wilt.

Reduce fertility stress: increase nitrogen input as is feasible

Reduce mowing stress: raise height of cut as is feasible.

Select best fungicide: use published fungicide trial information from plant pathology researchers across the United States.

For up-to-date fungicide recommendations I suggest the University of Kentucky 2011 Chemical Control of Turfgrass Disease guide

Derek Settle, PhD
Director of Turfgrass Program
Chicago District Golf Association
11855 Archer Ave
Lemont, IL 60439

Monday, June 20, 2011

Interseeding Improved Cultivars of Creeping Bentgrass into Existing Putting Greens


Marcus A. Jones and Nick E. Christians

Introduction
Recently released cultivars of creeping bentgrass are available that possess more desirable agronomic characteristics. Traditional conversion involving the use of non-selective herbicides or soil fumigants is costly and time consuming. Interseeding has been proposed as an alternative conversion method. Interseeding is a method of conversion where seed is sown into an established grass sward. The goal is for the introduced cultivar or species to become the major component of the sward over time.

A variety of factors influence the success of interseeding. Gap size has been found to influence the early success of seedlings. However, significant disruption to the canopy would reduce the uniformity of the playing surface and may not be desirable to golfers.

Factors such as germination speed and seed size have also been found to influence the success of seed sown into areas with established plants. In addition, research shows that seeding at above average rates has been advantageous when trying to establish turf cover when traffic is present.

The objectives of this study were to evaluate the ability of converting an established golf course putting green via interseeding.

Materials and Methods
An interseeding study was conducted on an established practice putting green at Hyperion Field Club in Johnston, Iowa and on a research putting green in 2009 and 2010. Four replications arranged in a split block experimental design were used to evaluate three plant protectants (main plots) and two seeding regimes (subplot within main plot). Main plots treatments included a non-treated control, applications of Velocity herbicide, or Trimmit plant growth regulator. Sub plot treatments included seed sown into the canopy twice or nine times.

A Maredo seeder with vibratory spikes was used throughout the season to seed into the existing canopy at 1.5 lb/1000ft2 for seasonal totals of 4.5 or 13.5 lbs/1000ft2. Velocity was applied every 14 days at 2 oz/A starting 4 June 2010 and concluding 16 July 2010 for a total of four applications. A fifth and final application of Velocity was made 1 October 2010 at the same rate. Trimmit was applied every 14 days at 6 oz/A starting 4 June 2010 and concluding 10 September 2010 for a total of eight applications.

Regular maintenance practices were only slightly altered as the goal was to preserve conditions that would be conducive for the play of golf. Irrigation via hand-watering was conducted during the summer months in order to provide moisture to promote germination. Regular maintenance included mowing performed daily to a height of 0.125 in. and overhead irrigation was applied as necessary. Fertilizer (7N-7P-7K) was applied at a rate of 0.25 lb N/1000 ft2 each month of the growing season and diseases and insects were controlled as necessary.

Plant samples were collected during the fall of each year prior to snowfall and the following spring for evaluation of Penn A-4 populations. Cultivar identification was performed by using random amplified polymorphic DNA markers.

Results and Discussion
Five months after initial seeding, the 4.5 and 13.5 lb/1000 ft2 seeding regimes resulted in a 19 and 39 percent conversion to Penn A-4, respectively (Figure 1). However, twelve months after initial seeding, Penn A-4 populations were reduced to 1 and 8 percent for the 4.5 and 13.5 lb/1000 ft2 seeding rate, respectively (Figure 2).

Figure 1. Percentage conversion of an established putting green to Penn A-4, five months after initial seeding.  Values within seeding regimes followed by the same letter are not different at P = .05

Figure 2. Percentage conversion of an established putting green to Penn A-4, 12 months after initial seeding. Values within seeding regimes followed by the same letter are not different at P = .05

These data indicate a transient shift to Penn A-4 occurred but was not able to persist. Additionally, applications of Velocity or Trimmit did not hasten conversion to Penn A-4 (Figures 1 and 2). The lack of establishment is likely due to competition from the surrounding turf and mechanical and environmental stresses.

During the first year of the study, the percentage of annual bluegrass was reduced from approximately 60 to 20 percent in plots treated with Velocity. No loss of density occurred, but phytotoxicity was observed in plots treated with Velocity. Significant loss of density was observed during the second year of the study from Velocity applications.

Conversion was more persistent on the research putting green. The 13.5 lb/1000 ft2 seeding regime resulted in a 42% establishment of Penn A-4 the fall following interseeding (Figure 3). Evaluation of the plots the following spring revealed 45% Penn A-4 still present. Although interseeding was more successful in the research setting, the overall quality of the turf would not be acceptable for most putting greens.

Figure 3. Percentage conversion of a research putting green to Penn A-4. Values followed by the same letter are not different at P = .05
These results suggest that the level of maintenance and overall quality of the putting surface influence the success of conversion. Conversion through interseeding in this study was not successful when the plots were maintained under golf course conditions. Interseeding was only successful when conditions were allowed to deteriorate below acceptable levels. The overall conditioning of the putting surface in order to permit interseeding needs to be weighed against the cost of a traditional conversion when deciding on a renovation program.

Marcus Jones
Assistant Scientist

Thursday, June 16, 2011

IMPRELIS DAMAGE ON TREES

Nick Christians
June 16, 2011


Imprelis (aminocyclopyrachlor) was released by DuPont Professional Products into the turf market this spring as a broadleaf control. It is part of a new chemical subclass called pyrimidine carboxylic acids. We have studied this product experimentally at Iowa State for the past couple of years and have found it to be very effective against a broad spectrum of broadleaf weeds. Its advantage is that it is effective against several hard to control weeds such as ground ivy, violets, and henbit. It also has the advantages of being applied at very low rates of active ingredient and is rainfast, meaning that it does not need to remain on the weed leaves for a period of time. It's safe on most cool-season grasses and some warm-season grasses, including zoysiagrass.

In early June, a number of reports on tree damage on areas treated with Imprelis began to come in. The first reports that I heard were from the east coast. Then pictures and reports started coming in from Chicago. Yesterday, I heard that there are several reports from the Atlanta area. The two most commonly damaged trees have been Norway spruce and white pine.

It is important to note that there are many locations where the product was used and no tree damage has occurred. Also, not all trees on the treated areas are damaged.

The pictures below are Norway Spruce and were taken in the Chicago area. The damage appears to be systemic, meaning that the material is being taken up by the roots and translocated to new growth. On this site, about 20 trees out of approximately 120 susceptible plants were damaged. In this case, there was heavy rain after treatment that may have increased movement of the product into the rootzone.

Dupont released a letter last night to users of the product. Their recommendation is as follows:

"As a precaution, until we can more fully understand the circumstances, and whether Imprelis may have contributed to the observed symptoms, do not apply Imprelis where Norway Spruce or White Pine are present on, or in close proximity to, the property to be treated.  Additionally, when applying Imprelis, be careful that no spray treatment, drift or runoff occurs that could make contact with trees, shrubs and other desirable plants, and stay well away from exposed roots and the rootzone of trees and shrubs.  Consult a certified arborist if you are uncertain about the root zone of specific tree species."

My personal recommendation is to be very cautious with the use of this product until we know exactly what is going on. This story is just developing and I will keep you posted as new information is released.


Here are some additional links.


http://www.ppdl.purdue.edu/PPDL/hot11/6-10.html

http://bygl.osu.edu/#5

http://extension.psu.edu/greenindustry/giec/news/2011/heads-up-spruce-and-pine-injury








Monday, June 6, 2011

BUNKER LINERS-TIMOTHY CHRISTIANS

Nick Christians
June 6, 2011

Here is a post from Tim Christians, superintendent of Makray Memorial Golf Club in Barington, Ill.

It shows two bunkers the morning after a 1.78 rain. The first one has no liner and the second one has something called the Sand Dam Bunker liner. There is quite a difference.





May 2011 Weather Recap

A number of golf courses experienced severe weather during the month of May.

Although summer doesn’t officially begin until the 21st of this month, the state will experience mid-summer temperatures during the first half of this week. Dollar spot has been active for a couple weeks now and brown patch and pythium blight could make an appearance the next couple of days with the temperatures expected to be in the mid-90’s. Let’s take a quick look at the weather the state experienced in May.


Air temperatures during the month of May averaged 60 degrees which is 1.3 degrees cooler than average. The warmest day of the month occurred on May 10th as daytime air temperatures climbed above 90 degrees. The coolest day of the month occurred just four days later as temperatures plummeted to 49 degrees. Soil temperatures slowly rose throughout the month from the mid-60’s and climbed into the low 70’s towards the end of the month

After record rainfalls during the summer of 2010, it appears we could be headed down the same road again this season. May rainfall amounts totaled 5.61 inches or 1.26 inches above normal. Since May 1, central Iowa has received over 10.5 inches of rain from 35 rainfall events. During this same time period last year we had received 9.5 inches of rain from 33 rainfall events.

The month of May also saw a number of severe weather events with strong winds, thunder, and lightning. Turf areas can be a dangerous place to be during thunderstorms because they are generally open areas scattered with individual trees. A lightning bolt will take the shortest route between the cloud and the ground, which means that a golfer standing in the middle of a fairway or huddled under a tree is a prime target for a strike.

One golf course in central Iowa experienced a lightning strike on a putting green.  Remember to remind your crew about lightning safety.

The Golf Course Superintendent Association America of America (GCSAA) publishes a list of lightning safety tips. Take time to review these safety points with your crews as we enter the summer season.

•  Seek shelter at the first sign of a thunderstorm. If the course's warning system sounds, take cover.

•  If possible, get off the golf course or go to a designated lightning shelter.

•  Do not stand under a lone tree. This is where most people are injured or killed.
•  Stay away from water.

•  Stay away from your golf clubs.

•  If your shoes have metal spikes, take them off.

•  Move away from your golf cart.

•  If stranded in the open, go to a low place such as a ravine or valley.

Marcus Jones
Assistant Scientist

Wednesday, June 1, 2011

2010 Creeping Bentgrass-Dollar Spot Study

Nick Christians

June 1, 2011

This is the first of the 2011 research reports. It includes the 2010 results from our trial on creeping bentgrasses maintained at both fairway and green height. Tables 3 and 4 are jpg photos and you will need to click on them to be able to read them.



Creeping Bentgrass Dollar Spot Study

Christopher J. Blume and Nick E. Christians

Objectives

The objectives of this study are to determine the susceptibility of creeping bentgrass (Agrostis stolonifera) cultivars to dollar spot (Sclerotinia homeocarpa) under both green height and fairway height.

Materials and Methods

This fairway height (0.5”) and green height (0.25”) studies are being conducted at the Iowa State University Turfgrass Research Station it is part of a regional project being conducted at several of the Midwestern Universities. Both studies included 24 cultivars, although some of the cultivars differed on the two sites (Table 1). The green-height study area was established on a sand-capped area, and the fairway-height area was established on a native soil area (Nicollet clay-loam).

Both studies were established 17 September, 2008. The plots were allowed to mature until the spring of 2009. The plots were then split into untreated and fungicide treated halves. The study was conducted as a randomized split block design, with three replications.

Fungicide treatment timing was based on the cultivar ‘Declaration’, which is the most dollar spot tolerant cultivar in the study. Treatments were made to the green height plots when ‘Declaration’ was observed to have at least 5% of the plot area infested with dollar spot. The fairway height study area was treated when ‘Declaration’ was observed to have at least 10% of the plot area infested.

The fungicide mixture consisted of Emerald (0.18 oz product/1000ft2) and Daconil Ultrex (3.2 oz product/1000ft2), applied in 2 gallons water/1000ft2. The applications were applied using a modified spray boom, with two TeeJet XR flat fan nozzles. In 2010, three applications were made 24 June, 19 August, and 4 October.

Results

‘Memorial’ and ‘Penncross’, and ‘LS-44’ had the best quality ratings in the green height study in 2010, whereas ‘Allister’ received the lowest rating. In the fairway height study, ‘Alpha’, ‘LS-44’, and ‘Memorial’ were the highest rated cultivars, and ‘Independence’, ‘Declaration’ and ‘SR 1150’ received the lowest quality ratings (Table 2).

‘Century’ and ‘Imperial’ showed the most damage from dollar spot in both September and October in the green height study (Table 3). ‘Memorial’, ‘Declaration’, and ‘Crystal Bluelinks’ had the least damage in untreated plots at the end of the season.

There was not as much dollar spot in 2010 as there was in 2009 on the fairway height bentgrass. At the first two ratings of the season, there was more dollar spot in the treated side than in the untreated side of the plot. These plots had not been treated since the fall before. The reason for this observation is unknown. In August, no dollar spot was observed on treated or on untreated sides of the plot. In September, ‘Southshore’ and ‘Century’ had the most dollar spot on the untreated side of the plots, whereas ‘Memorial’, ‘Independence’, and ‘Declaration’ had the least dollar spot. In October, ‘Crenshaw’ and ‘Century’ had the most dollar spot and ‘Memorial’, ‘Alister’, ‘Pennlinks II’ and ‘Memorial’ had the least (Table 4).

Table 1. Varieties of creeping bentgrass in commercial bentgrass demonstration trial.

Entry No.

Fairway Height Varieties

Green Height Varieties

1

L-93

L-93

2

T-1

T-1

3

Alpha

Alpha

4

Putter

Putter

5

Southshore

Southshore

6

Kingpin

Kingpin

7

Crenshaw

Crenshaw

8

Imperial

Imperial

9

Century

Century

10

Penncross

Penncross

11

A-4

A-4

12

Crystal bluelinks

Crystal bluelinks

13

Alister

Penn A-1

14

Pennlinks II

Penn G-6

15

007

007

16

MacKenzie

MacKenzie

17

Tyee

Tyee

18

SR 1150

SR 1150

19

Memorial

Memorial

20

Independence

Independence

21

Declaration

Declaration

22

LS - 44

LS - 44

23

Bengal

Bengal

24

Penn G-6

Alister

Table 2. Quality ratings for green-height and fairway-height cultivars of the creeping bentgrass demonstration trial.


Quality


Quality

Cultivars (green)

2010

Cultivars (fairway)

2010

L-93

5.9β

L-93

6.4β

T-1

5.4

T-1

6.2

Alpha

5.4

Alpha

6.6

Putter

5.8

Putter

6.2

Southshore

5.8

Southshore

6.0

Kingpin

5.7

Kingpin

6.3

Crenshaw

6.2

Crenshaw

5.9

Imperial

5.6

Imperial

6.3

Century

5.5

Century

5.9

Penncross

6.2

Penncross

6.0

A-4

5.6

A-4

6.0

Crystal bluelinks

6.1

Crystal bluelinks

6.4

Penn A-1

5.9

Alister

6.1

Penn G-6

6.1

Pennlinks II

6.1

007

5.1

007

6.2

MacKenzie

5.3

MacKenzie

6.2

Tyee

5.0

Tyee

6.0

SR 1150

4.7

SR 1150

5.8

Memorial

6.3

Memorial

6.5

Independence

5.1

Independence

5.6

Declaration

5.0

Declaration

5.7

LS-44

6.2

LS-44

6.5

Bengal

5.7

Bengal

6.4

Alister

4.2

Penn G-6

6.4

LSD(0.05)

0.9

LSD(0.05)

0.6

Quality data rated on a scale of 9-1, with 9 = excellent turf; 1 = poorest quality; 6 = minimally acceptable.

Ratings are the average of three replications, averaged over the months of June to October.

Ratings observed only on fungicide-treated side of plot area.

βRatings are the average of three replications, averaged over the months of May to October.