Winter Injury Guide

I have put together a quick little guide book for our membership to understand some of the winter turf injury sustained on the golf course this season.  Some of the injury is intentional, some is desired and some is not. Either way the guide shows in basic terms what each injury looks like and the cause of it.  Sometimes  Mother Nature provides the best selective herbicide on the market. 

Winter Injury Guide

Crown Hydration:  Occurs when large amounts of surface water from snow melt turns into ice crystals outside the plant cell (extracellular) of the Turfgrass crown tissue. As these ice crystals form and enlarge, they pull water out of the cell, which will result in dehydration. At some point a dehydrated cell and cell membrane stop functioning and the result is cell death. Many times superficial damage occurs but If enough of the cells in the crown of the plant die, the entire Turfgrass plant will die as a result.

Figure 1 Hole #5 1st Fairway Under Trees

Figure 2  Hole #6 Fairway and Rough Sheet Water Flow Areas

Desiccation: Winter desiccation is the death of leaves or plants by drying during winter when the plant is either dormant or semi-dormant. Desiccation injury is usually greatest on exposed or elevated sites and areas where surface runoff is great. Tree root completion for water also affects the quality of the Turfgrass.

Figure 3 Hole #7 Exposed South Facing Mounds

                                                                   

Figure 4 Hole #4 Tree Root Competition For Water

Selective Herbicide Kill: Selective herbicides kill specific targets, while leaving the desired turf species relatively unharmed. We are using both older and newer chemistries to control Poa Annua in our key playing areas.

Figure 5 Hole #7 Fairway Poa Kill

Figure 6 North Chipping Green PoaCure Trials

A Look At Our Operation

A couple of weeks ago we shot a video that is being done for the club's website that shows my staff in action as well as explaining our current green renovation project.

This video gives great information about our operation in addition to explaining the detailed steps involved in the renovation process of the putting green. These steps are explained and also insight is given as to why we are trying to eliminate Poa Annua from our greens. 

 The company that is doing our video production is called Oswego Creative and they do great work check them out Here

Breaking The Cycle

Over the years we have had many construction and or renovation projects on the golf course and the one thing we have always been short on was time.  In the past things have always been forced into a small time frame that best meets the needs for the course to be playable at all times. We are an extremely busy private Country Club that does more rounds in a year than some of our surrounding public golf courses. This high demand for golf has pushed us into a corner in some of our past projects that did not turn out as well as they should have.

This cycle is now being broken and the culture of the club needs to follow as well.  With our latest project of re-grassing the putting green we are approaching this with a much different view than before.  We will be doing things on a time schedule that best fits the agronomic health of the turf, not a golf schedule of events to be ready for.

This can be best described by what is taking place with the fumigation process at the putting green. The normal fumigation timeline takes between 7-10 days to complete based on soil temperatures. After closely monitoring the soil temperatures we could have ended the fumigation on the seventh day, but I decided with everything that is at stake with the success of this project the fumigation was allowed to go for another day and a half.  This decision was based on what will allow us to have the most success with this project moving forward. If it means extending the fumigation timeline and delaying the eventual re-seeding of the putting green than so be it. We all want this re-grassing to be a success, so why should we not set ourself up for success rather than failure.

Today wewill begin the re-grading of the green in preparation of the seeding process. We will be using the pea gravel layer below the mix as our guide for the final grade above.  If all goes according to plan we should be able to have the green with a final grade on it by tomorrow and seed will be sown immediately following.

The weather forecast looks good for at least the next week, so germination should be achieved beginning five days from planting. Exciting times are just ahead of us, I hope you enjoy watching the grass grow as much as I will.

A Mulligan

We are now in the final stretch of the fumigation process on the practice putting green. Last week we began the renovation of the putting green as another piece of the puzzle to move down the road of re-grassing all of the greens on the golf course.

The renovation of the green occurs in a multi step process that each has to occur in a specific order in to achieve the desired goal. Right now it appears that with all of the water running on the green that we have already seeded the green and are on our way back. This is not the case, we are actually using the water as a part of the fumigation process. The water helps trap the fumigant in the sand by acting as a seal on the surface thereby allowing the weed seeds to be successfully killed off in the rootzone mix. This process last between 7 to 10 days depending on the soil temperatures. After that has occurred the gas needs to blow off for a couple days before it is safe to re-seed the green. It is in this time that we will be working on the final surface grading and prep before we can seed the new T-1 Bentgrass.

Currently I am anticipating new seed going down on Friday the 17th weather and final grading dependent. Below are a few photos that show the highlights of the renovation process.

Sod Cutting Of The Green

Removal Of Sod

Tilling The Rootzone

Applying The Fumigant

Connect The Dots

Some of you might have noticed the white dots that are located around the putting green and are wondering what they are. These dots are identifying the original edge of the putting green that has shrunk in over time. Beginning next Monday August 6th we will be renovating the putting green and begin a re-grassing protocol. This will be identical to what was done to the north chipping green last summer with exceptional results. The point of this renovation is to eliminate the Poa Annua from the green and establish a pure Bentgrass putting surface that will provide an example of what we can have in the future. The green will be closed for the remainder of the season to allow for a re-establishment from seed using a new "super" Bentgrass called T-1. This new variety has a tremendous density which naturally keeps out Poa in addition to providing a consistently smooth fast putting surface. During the time that the putting green is being renovated the north chipping green will become the temporary practice putting green. This will give you a chance to begin to see and feel how this new grass performs. I will be documenting this renovation process here, so check back in frequently to watch the new green come back to life.

Beware In Colorado

On the heals of my previous post about treating Poa Annua comes a turn of events.  If you are brave enough to apply Xonerate be sure to read the product label not once, not twice or even a third time of which might not be enough to truly understand the product being applied.  I have found it's what is not on the label that can give the best advice on how to use a product properly.  Unfortunately this knowledge comes with a price.  It seems as this information is only available after the fact of injury occurring to the desired plant species which in our case was  Bentgrass. This information was given to me more 30 days after the product was registered for use in Colorado and the application protocol had apparently changed.  Far too late for me or anyone who had applied the product per label instructions.

In my opinion Arysta LifeScience the producers of Xonerate herbicide was only concerned with getting the product to market without thoroughly testing it in all markets before release.  The latest and greatest Poa control product can yield a fortune in revenue coming back into the company that can expedite the return on investment.  This was clearly the case in Colorado.  In the last week I have received several phone calls from fellow Superintendents in Colorado who are experiencing the same if not worse injury to Bentgrass. To make matters worse the product Xonerate had little or no control on the Poa Annua which it is supposedly works so well on.  Most of my Poa that was treated couldn't look healthier, while the amount damage that occurred to the Bentgrass  makes this product unusable for me going forward.  This is the exact opposite of how this product has been marketed.

I believe a big factor in using this product in Colorado was overlooked and or underestimated.  Xonerate works by inhibiting Photosynthesis within the plant (specifically Poa Annua)  and is absorbed through both  the leaf and through the root system. The combination of  low humidity and significantly higher intensity of sun rays appear to effect how the product is absorbed by the non target species (Bentgrass).  More research and testing needs to be done on this matter.

We as Golf Course Superintendents are always looking for products to improve the overall health and playability of the golf course and it's times like this that some of these latest and greatest product make matters worse. If there are changes to application protocols manufacturers need to tell someone in a proactive manner , don't keep this information internally let the sales reps know so they can effectively communicate to the end user.

So if your a Golf Course Superintendent in Colorado considering using Xonerate, I would think long and hard before taking that first step because you will get burned. Just ask me.

Poa Annua Under Fire

 Over the years we have used many different products to try and control Poa Annua, each with varying degrees of success. 

Currently we are testing a newly labeled product called Xonerate for Poa Annua control.  We began our testing on several areas of the golf course including #11 first fairway, 1/2 of #11 green, North chipping and nursery greens and fairways.

After closely following the application protocols over the last six weeks visual disruption is taking place on some of the turf areas.  Most notably the first fairway on hole #11 is showing signs of both Poa Annua stress as well as some Bentgrass stress.  I am happy about the Poa being under stress, not so much with the Bent.  Most of the damage to the Bent is in the form of leaf tip burn and or stress.  The crown of the plant still looks healthly and active.  Over the next several weeks the plant should push out new leaf material and the visual disruption will recede.

It is exciting to see new products come to the market, but if they are not safe on the desired plant species then it really doesn't help my overall battle against Poa Annua.

To learn more about the product Xonerate Here

What Is The Yellow Grass In The Fairways?

Throughout the fairways there are many areas that are off color and under stress, this is an intended effect from the use of herbicide that targets Poa Annua.

The fairways have received successive applications of Velocity to help control the Poa populations and this is what has caused the visible signs of turf injury. Currently the Poa is not dead, but it is under severe stress and the plant is in shut down mode which will help the desired Bentgrass to out compete it for space in the fairways.

We will be backing down the future applications so that unacceptable turf discoloration does not persist into the upcoming Member/Guest tournament in a few weeks.

Off Color

In the fairways there are many areas that are discolored causing the fairway to look splotchy. This discoloration is the result of successive PGR (plant growth regulator) applications that target Poa Annua.

Discolored Poa Annua

Throughout the season we have been applying a rotation of different PGR's to the fairways on a weekly basis. The Poa is finally being discolored and weakened due to the cumulative effects of the chemical regulation in combination to warm weather finally arriving. Although the Poa is not dead, it is severely hurt and this will allow the Bentgrass to out compete it for surface area on the fairway. This is one of my key agronomic techniques that helps us control the level of Poa Annua populations in addition to tipping the scales in favor of Bentgrass the desired species.

Poa Management

As the greens are beginning to come out of dormancy, the injured Poa Annua is showing the effects of chemical treatment from last fall. Back in October the greens were treated with high rates of TGR (a plant growth regulator) to weaken and kill the Poa. These spots are now visible on the greens where the Poa is bleached out or white in color.

Poa Annua is a winter annual that begins to actively grow before the Bentgrass, which gives the Poa a competitive advantage. The chemical treatment has shifted the competitive balance in favor of the Bentgrass which, will now be able to reclaim some of the ground lost to the Poa over time. Fertility will be geared toward encouraging the Bentgrass to grow and fill in the voids created by the Poa Annua.

Poa Annua Management

It is around this time every year that I get asked “what is going on with the Poa”? The Poa Annua is most active in the spring and fall, when the temperatures are cooler and more conducive to growth. When the heat of the summer kicks in the Poa slows down and merely tries to hang on until the cooler temperatures return.

Up until this point we have only been able to try and regulate the seedhead production of the Poa, due to the limited chemical options based on still being in the frost window. Now that the danger of a hard frost has passed we now can begin our summer long chemical applications that will weaken and even kill the Poa Annua if timed correctly.

These products will give the Bentgrass on both the greens and fairways a completive advantage and out compete the Poa for species dominance. As progressive regulation takes place, the Poa it will become discolored and start to shrink down into the canopy and the Bentgrass will begin encroaching into the weakened areas.

Growth Regulators

Growth regulation products are commonly applied to many of the playing surfaces on the golf course such as, greens, tees and fairways. The use of PGR’s or plant growth regulators consistently improves overall turfgrass quality by promoting a smooth uniform playing surface, aides in color enhancement and improves stress tolerance.
Spraying PGR's on Fairways

PGR’s are generally classified into two different categories type I and type II. Type I PGR’s suppress plant growth by inhibiting cell division and help with the prevention of seedhead production. These products are typically foliar absorbed by the plant. Type II PGR’s suppress plant growth by limiting cell elongation and Gibberellin production which reduces growth rate. These products are can be either foliar or root absorbed.

The use of specific growth regulators also helps with controlling Poa Annua populations by weakening the Poa and allowing the desired grass species a competitive advantage. When the Poa is targeted for suppression it can be severely injured and or killed if that is the desired effect. When proper rates and application timing of PGR’s is done they can be one of the best agronomic tools available for Golf Course Superintendent’s.
Close up of Injured Poa Annua

Seedhead Suppression

One of the biggest challenges in maintaining high quality Bentgrass/ Poa Putting greens is having the two different grass type’s acting as one. Each grass type has its own growth habit and growth rate, and to top it off the Poa Annua is a prolific seedhead producer.

Here at CCCP we have relatively low populations (10%-20%) of Poa Annua on our greens which says a lot for greens that are 23 years old. We have been extremely committed over the years in trying to manage the Poa infestation and have actually reduced the total populations over time.

One of the methods of managing the Poa populations comes through applications of PGR’s (plant growth regulators) for seedhead suppression. These applications are made just before the actual seedheads are visible and if timed right the production of seedheads will not occur. There are several methods for determining the timing such as Degree days and phenological indicators.

Degree -Days
The weather plays a major role in determining the rate of plant growth and development and influences development of insect life cycles and plant disease cycles, which is why trying to make pesticide applications by calendar dates, is not very effective. Degree-day accumulations are a measurement of air temperatures above a predetermined base temperature. Insect development is often tracked according to the accumulation of a specific number of temperature units called growing degree days (GDD), a simple, temperature-derived index. Growth and development of many insects and plants depend upon the amount of heat present in or around the organism. Most plants and animals develop when temperatures fall within a specific range.

Phenological Indicators

While degree days are dependent solely on air temperature, the use of plant phenological indicators takes into account the influence of other climatic factors. They provide an accurate, low-cost predictive tool where weather data is not available or practical to track. Soil and air temperatures, rainfall, humidity and exposure are all contributing factors. Plant phenological indicators reflect the development of insects and plants within the many microclimates in a landscape.
I have found tracking Forsythia bloom to be the most effective tool for timing the applications of PGR’s to our location.

Discoloration on The Greens

The discolored spots you are seeing on #4,#10 and #12 greens are not winter kill, but rather chemical suppression of Poa Annua. Throughout the year we treat all of the playing surfaces for Poa Annua control. These applications come in two different forms the first is a pre-emergent application and the second is a post emergent.
The pre-emergent herbicides are applied to the greens each spring and fall just prior to aerification. This is done so that the voids that are created by the aerification holes do not germinate with Poa Annua.
The post emergent applications are made on a weekly basis to the greens and fairways, and the main objectives of these are to reduce the completive advantage of the Poa. When the Poa is in a weakened state the Bentgrass is better able out grow and out compete the Poa for the surface space.