Emerald Ash Borer at Midland / Spruce and Pine Diseases

On January 18, I confirmed, for the first time, that Emerald Ash Borer (EAB) has inhabited the Ash tree population on Midland’s property. We have been inside the Minnesota Department of Agriculture’s quarantine zone for several years now, so this is no surprise-but this is the first time that I’ve been able to make a positive identification on property.

We adopted a formal Tree Management Plan in 2009-one of the main reasons being the eventual infestation of the Emerald Ash Borer. In 2009, we had more than 600 Ash trees on the interior of the golf course. Fast forward to 2017: we now have fewer than 50. We knew that the infestation was inevitable, based on what’s taken place in cities east of us. The one thing we didn’t know was how long it would take until the population of insects grew large enough to do catastrophic damage to the Ash trees. We still don’t know that answer to that question.

Emerald Ash Borer is believed to have reached the United States in the late 1990’s, with the first confirmed case in Eastern Michigan, near Detroit, in 2002. The first confirmed case of EAB in Minnesota was in the spring of 2009. The adult beetles nibble on ash foliage but cause little damage. However, the adult’s eggs which turn into larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. Emerald Ash Borer probably arrived in the United States on wood packing material carried in cargo ships or airplanes originating in its native Asia. Since the early 2000’s, it’s killed hundreds of millions of ash trees in North America; caused regulatory agencies and the USDA to enforce quarantines and fines to prevent potentially infested ash trees, logs or hardwood firewood from moving out of areas where EAB occurs; and has cost municipalities, property owners, nursery operators and forest products industries hundreds of millions of dollars.

Below is a map of states affected by EAB. Areas highlighted in yellow and outlined in red are those infested by EAB and quarantined.

Each state has varying degrees of infestation and damage, mostly due to weather patterns and the speed of the beetle’s reproduction. Weather has been proven to affect the beetle’s ability to spread, particularly if the summer months are wet and the winters are not abnormally cold. Our summers and winters in Minnesota for the past several years have followed that trend, and we are seeing the spread of the beetle reflect that.

Although a full outbreak of Ash death has not yet occurred in widespread areas in Minneapolis/St. Paul, below is a common sight-showing how quickly the insect will decimate the Ash tree population.


The picture below is an Ash that I had been watching for several years at Midland. Notice the missing leaves at the tips and the dieback of branching, as well as a thicker canopy on the interior of the tree, all red flags that point towards an EAB infestation.

Here is the same tree this January without leaves. You can see that the Ash branches have lost their bark-a giveaway for Emerald Ash Borer advanced activity.


Finally, below is evidence of the damage the beetle’s larvae do below the bark of the tree, preventing it from transferring water and nutrients within itself, which eventually leads to its death. Our Ash tree population was planted in the 1950s, making them all approximately 60-70 years old. At this age, Green Ash usually show signs of normal decline on the backside of their lives, making them even more susceptible to EAB. The fact that 99% of the Ash are all the same age, and in decline, coupled with EAB on the rise, has led us to accelerate their removal in recent years at Midland.


When the Tree Management Plan was adopted at Midland , it identified the liability the Ash tree posed to the club if the total population of Ash was lost in a short period of time. The expense of this uncertainty is one of the reasons Ash trees have been removed steadily since 2009. Green and White Ash are native to Minnesota (with a population over 1 billion), but Midland’s percentage of Ash in its total tree population made it prudent for us to act before we saw an EAB infestation. We made the right decision to proactively manage the liability it posed. We also decided that preventively treating our entire Ash population was neither sustainable, nor a good business decision. Treatments would need to be made every three years, and once started, they would need to continue for the rest of the tree’s life. The expense to treat 600 Ash would be just over $100,000 every cycle. Midland decided to increase its tree inventory and diversity with native trees that we hope will resist future insects and diseases.

So how have we dealt with removing more than 500 Ash trees since 2009? We’ve invested in proper equipment, resources, training and a lot of full-time labor. The majority of work has been ongoing during the winter months over the past 8 years by Midland’s full-time staff.


One of the questions I get asked most often is “What do you and your staff do all winter?” Along with all of our other routine responsibilities, such as snow removal, course accessory refurbishing, budgeting, planning, equipment detailing, repairs and fabrication, as well as facility improvements, tree removals take place. Almost every day since the golf course has closed, our staff has been working on the tree removal process. Unless the temperatures are near single-digits, we have maintained constant progress with the removals; carefully felling the trees, limbing them up, wood-chipping what fits through the chipper, logging out sections into firewood to be split at a later time, logging the large trunks into mill-able sections, and raking up the endless sticks that break off and scatter when a tree is dropped. The stumps and their root-flares are then ground at least a foot deep, they’re filled/tamped with soil, seeded, covered, weeded, fertilized and watered until they grow in.

Why have we done the work in-house? If we were to contract what we are doing now, and removing the remaining logs and wood chips off property, it would cost Midland approximately $1,000 per tree. People don’t often think of the true cost of the a tree when it’s planted: the cost of maintaining that tree throughout its life, including normal limbing, storm damage trimming, string trimming the turf around the tree every 14 days, and the inevitable removal process. The cost of a tree on a golf course is very high and often grossly underestimated.

We have developed a system that uses the Turfgrass Department’s full-time staff to complete the skilled removals, its mechanics to keep the equipment operating at a high level, and the investment in resources to keep those costs at a minimum to the club by striving toward being very efficient. We split the small sections of wood to burn in the fire pits behind the clubhouse in the winter months; the log chunks are hauled off by an individual who heats a commercial storage building; the wood chips are hauled off property and used by the City of Roseville in their playgrounds, parks and trails; and finally, the straight trunks are milled to the left of #12 into lumber that is used to finish basements, build decks, small construction projects, renovating our golf course benches, making new tee markers and 150 yard stakes, and other small construction projects. We’ve eliminated a large financial burden to the club by being creative and finding avenues to legally rid ourselves of the massive amounts of wood and wood chips without a cost to the club.


So what is the plan going forward? We’ve reduced the number of Ash to a reasonable amount, so that when the EAB population explosion does take place, we are left with a situation that is manageable. We are treating only a few Ash trees on property with a preventative insecticide-those we’ve identified as important to keep alive while the newly planted desirable trees mature enough to provide similar impact as the current Ash.











The good part of the situation is that we have a long-range Tree Management Plan for our existing tree inventory, as well as a plan for planting new varieties of trees. The Tree Plan also gets us closer to some of the original design aspects Seth Raynor intended when he left only the native trees that provided strategy-recapturing wider angles of play that increase player enjoyment, much improved turf conditions with more sunlight, air movement, less  tree root competition, and highlighting restored vistas throughout the “Hills of Midland.”

If you’d like to read more about our Tree Management Plan, click on the link below to find a blog post I wrote 2 years ago: http://www.mhccturf.com/?p=291


Spruce and Pine Trees 

During the 1950’s, Midland unfortunately also planted Spruce and Pines in large numbers. These trees are also 60-70 years old, some are in decline, and are currently battling two diseases as well as an insect infestation.

  • Spruce

The Spruce on property are battling two diseases that specifically attack the needles and branches of the trees: Cytospora Canker and Rhizosphaera Needle Cast.

Colorado and Norway Spruce trees are dramatically affected by the Canker, which interestingly, affects only trees outside of their native ranges (which is unfortunately not Minnesota). This disease affects the branching of the tree and slowly leads to its death. It can affect branches low or high on the tree and spreads through spores when it rains or during nighttime irrigation cycles, which makes its dispersion very contagious and unpredictable. When Cankers form on a Spruce, it often starts to excrete a white/purplish resin outside of the bark, shown in the pictures below. Branches will quickly lose their needles after browning takes place. Unfortunately, removing infected branches often spreads the disease by opening up the bark and exposing the fruiting bodies of the disease, promoting its spread. There are no treatments available; we can only try to contain the disease by removing dying branches during the winter months. With the number of Spruce on property, it is near impossible to reach every infected branch each year.


The Spruce on Midland property are also being attacked by Rhizosphaere Needle Cast, which again infects Colorado Blue and Norway Spruce not grown in their native landscapes. Needle Cast attacks the needles of the Spruce and can take up to one year from infection to showing signs of decline. Below are symptoms of the Needle Cast on property.


Again, in Midland’s Tree Management Plan, we are continually identifying infected trees to be removed and replaced with native Deciduous trees in the correct areas and in the correct quantities. The Spruce trees that were planted inside of the golf course at Midland were an unfortunate mistake. These trees don’t allow a golfer (of any skill) to advance the ball through them, so there is zero recovery from what could be a shot not considered terrible. They also block full sight through them, so they block vistas that were part of Seth Raynor’s routing of the course. Spruce block sunlight 12 months a year, leading to ice formation on playing surfaces during the winter months. Unfortunately they were planted in vast numbers (Spruce and Pine in 2009 consisted of 68% of the total tree population on the interior of the property), and they were planted in wrong locations. Originally there were no Spruce or Pine on the golf course, only native Elms, Oaks, Hackberry and Maples. Since the 1950’s, the Spruce and Pine became a part of the golf course’s identity. We don’t know what we had originally because we’re used to what we currently have.


  • Pine

The Pine trees on property are battling Diplodia Blight, which affects all of our varieties on property: Austrian, Red, Scots, and Jack Pines.

The disease attacks new and old shoots of the tree, leading to discoloration of the needles. As trees are infected with the fungus, they can become deformed, and eventually the needles die and fall off. Diplodia is also spread by wind, rain, irrigation, animals moving the spores throughout the tree, as well as dead needles lying on the ground. This disease has spread very rapidly over the past five years, I assume, as a result of the very wet summers we have experienced. The disease also overwinters in dead needles, pine cones and branches on the ground, making it spread throughout the pines on property. Treatment is unsustainable, and, given the age of the Pine inventory, not worth the resources. The disease leaves the trees susceptible to other pests, mainly the Pine Bark Beetle, which is starting to become more prevalent on property, and speeding the mortality rate of our Pine tree inventory.

Notice in the pictures below how the needles look droughty. It’s a common mistake to think the Pine trees need water; often it’s because they are too wet and promoting the spread of the fungus throughout the tree(s).


It’s very unfortunate that during the time Midland planted all of the Ash, Spruce and Pine trees, other clubs in town were planting Elm, Oak, Hackberry and Maple, which are now growing into great specimen trees. The Ash, Spruce and Pine trees were planted on our property with no thought or plan in regard to diversity, future liabilities, strategy or effect on the evolution of Midland’s classically-designed golf course. At the time, no one knew what the consequences were of planting such a large number of only a few varieties. Fast forward to today, and the Greens Committee and the Board of Directors has had the difficult task of fixing this problem by removing incorrect species and planting desirable trees for the next generation of players to come. I commend their effort in adopting a plan that, at times, isn’t popular. The Tree Plan is not only correcting current issues, but just as important, creates a corrective path for the future generations of players at Midland, and its golf course. We should take a lot of pride in the fact that we are being more proactive with our tree inventory and interested in getting the golf course restored to where it was originally in 1919. In my opinion, we are ahead of the curve in comparison to most golf courses and municipalities in the state.

We are not planning to remove every Spruce and Pine immediately. We evaluate the health of the trees each year, adapt our removal/planting plan based on what’s evolving on the course. There is no threat from the City of Roseville or the Minnesota Department of Agriculture to force us to remove any Ash, Spruce or Pine. However, you will see more Ash trees being removed in 2017 in surrounding cities than ever before. The city of St. Paul has done very little in the past and has now realized they need to play catch up to Minneapolis. 300 Ash at Highland GC and 175 Ash at Como GC have been removed in 2017 as city Foresters are realizing the insect is spreading and multiplying at a much quicker rate, leaving them vulnerable to removing even larger numbers when a population explosion takes place and widespread death to Ash is the consequence. St. Paul is currently spending $1 million per year in removals and new plantings. The City of Minneapolis is in the process of removing 50,000 Ash, 10,000 of which are in their parks and golf courses, and are spending $1.2 million annually. When widespread EAB destruction occurs in the furure, it will have significant financial repercussions for those who haven’t prepared.

Again, we have had a formal long-range plan in place since 2009 that is consistent from year to year in managing our tree inventory. We are not randomly removing any tree; the plan that is in place looks at trees from several different aspects and evaluates each step carefully.


Mike Manthey

22 Replies to “Emerald Ash Borer at Midland / Spruce and Pine Diseases”

  1. Paul Kirkegaard says:

    I am learning so much from your posts- thank-you! It really has been fun for me to walk the course this winter and see a bit of what all of you in the maintenance facility do for us and our course. Thanks to all of you and your team.

    1. Mike Manthey says:


      Thanks for the comments. We have a top-notch team! Also glad you’ve taken advantage of being on the course during the off-season.


  2. Marnie Myhre says:

    Thanks Mike for such a thorough explanation of the tree issue. It is really hard to see all the downed trees but hopeful to know there is a plan with new growth in the future. Trees add much beauty and interest to the game of golf, though that can be frustrating at times!

    1. Mike Manthey says:


      Thanks for reading. I agree, trees have their role on golf courses. There’s nothing better than a great specimen tree on the top of a hill or to accentuate a vista. Our Tree Plan balances the correct tree varieties, location and quantities to hopefully get the most enjoyment and challenge from all Midland members and their guests!


  3. Jack Schutz says:

    Fantastic article. Great job in getting ahead of the problems and doing the work in house!

    1. Mike Manthey says:


      Thank you for the support!


  4. Anonymous says:

    Thank you Mike. This is extremely informative and helpful.

    Greg Stevens

    1. Mike Manthey says:

      Thanks for reading Greg.


  5. Pat Gray says:

    Thanks Mike this is very informative and spells out exactly why we need to be diligent and remove deceased trees.

    1. Mike Manthey says:


      Thank and I completely agree. Glad we now a plan for the future.


  6. Bruce Drake says:

    Any evidence of blister rust on the white pines?

    1. Mike Manthey says:


      Yes, two years ago was the first time I’ve seen it. There is a small grove of White Pine front-right of the 10th tee. They are planted very close to each other, and we’ve had to remove infected trees to prevent spreading. Corrective pruning when the symptoms are visual is our game plan. That disease is relatively new to the metro, was historically common in north/northeast MN. Again, I think the record setting wet summers/falls we’ve had have spread it to this area. Keeping the branches limbed up off the ground will help prevent it but once a tree is infected, fairly difficult to cure unfortunately.

      Thanks for the question,

  7. Mike Graff says:

    Mike, excellent update! Thanks very much. Please add my email to your list!
    Mike Graff

    1. Mike Manthey says:

      Thanks for reading Mike, you’re signed up.


  8. Ken Kephart says:

    Interesting, thanks for detailed info. Would like to receive when new info available

  9. Fred Zonino says:

    Mike, great write up! For those of us who will have to explain the tree action when play starts can you bullet point some talking points around the issue? I think it would be helpful.

    1. Mike Manthey says:

      Thanks Fred, appreciated.

      MH Tree Management Plan

      1.Safety/Health of Trees: Currently managing Disease and Insects in Ash, Spruce and Pine. Once a tree is a safety concern to staff/players and/or infected with disease/insect, the Plan takes into account those aspects and decisions are made accordingly.

      2. Turf Health/Playability: Reducing morning shade, reducing tree root competition, while increasing Bentgrass and firmer/healthier playing surfaces, which need less inputs.

      3. Restoring Seth Raynor’s design intentions: Improving strategy by reducing punishment to higher handicap players, increasing it to who play to a lower handicap. Restoring width to the fairways by restoring original tree lines and placing new trees in the correct locations/and/or highlighting the native trees. Regaining the vistas, sightlines and infinity looks that Raynor was known for instituting in his designs. Promoting the showcase of the land on which the golf course lays upon, which Raynor was known as maybe the best classic-aged architect at getting the most out of the land and having it affect play.

      4. Diversity: Too high of a % of tree population is of Spruce, Pine and Ash. Now that they are starting to decline, leaves us with liabilities if they all decline rapidly at the same time.

      5. Increasing Native Tree Population: We are planting Elm, Oaks, Maples, Hackberry as these trees are native to this area and have proven to be the longest lasting tree in our environment.

      6. Short/Long Term Goals: We are correcting mistakes made 50-60 years ago. The Tree Plan looks at all holes independently and manages them accordingly. We make short term changes with the long term in mind. All change is difficult, but we making changes for the better/future of Midland.

      I go into more detail in the Tree Plan Post I made in 2015 if you or anyone is looking for more detail.

      As always, thanks for helping educate our Plan to the masses!

  10. FDZ says:

    Thanks for the bullets. I can probably get thru those in a couple of holes!

  11. Great post Mike! You are a good writer. I do miss felling trees on the course from time to time. I miss how peaceful the property is in the winter. Tell the crew I say hi!

    1. Mike Manthey says:

      Thanks Mitch. You were, hands down, one of the best with a saw! Winter on a golf course is underappreciated, very serene.

  12. DAve Sellergren says:

    WHaat species of evergreen can still be planted safely these days, not necessarily on MHCC grounds?

    1. Mike Manthey says:


      Good question. Here is a good link with some guidelines.

      It really depends on your site-specific conditions; soil type, sun/shade, and winter exposure, etc. Unfortunately, there are many diseases and insects that are attacking evergreens, mainly because they are not native and/or planted in the wrong conditions.

      I still like Eastern Red Cedar, Black Hills and Norway Spruce. Balsam Firs do well in wet soils which is common in our area as well.

      The perimeter of Midland’s property still has a lot of Ash trees. We are now starting to replant these areas in a long-range plan. The trees I’ve listed will be a part of that plan based on the location of the plantings.

      Take a look at the link from the UofM and let me know if you have questions.


Leave a Reply

Your email address will not be published.