Trunk Injection Treatments for Elm Scale on Campus

Some of the most impressive and interesting trees on our campus are the American and Augustine Elms.  We are lucky to have about 40 of these trees left on the main campus after the Dutch Elm Disease epidemic reached colorado in the 1980's, decimating elm populations along the Front Ranges' urban corridor.  We have not had any confirmed cases of Dutch Elm disease in the last decade but our Elm trees have suffered from other disorders and insect issues. 

One of the most damaging of the insect pests on our elms is the European Elm Scale, a very difficult pest to treat once it becomes established.  This insect is the armored scale present on the twigs and smaller branches of nearly any elm tree you might see in Boulder.  Many otherwise healthy and vigourous appearing elms have many small twigs denuded of their leaves due to the scale.  If unchecked, this dieback will move into increasingly larger diameter branches.  This scale insect is also the reason so many elm trees have massive amounts of "honeydew" misting off of them, sticking to everything under the tree.  This honeydew also feeds the production of the black sooty molds on the trunk and branches of the trees and on hardscapes around the tree.  Besides the nuisance factor, this insect is very hard on the trees' health, robbing the twigs and leaves of nutrients and opening the door to secondary decay organisms and weakening the tree substantially.

 

Over the past several years we have intermittently tried applying insecticides to our elm trees in an effort to slow down this insect.  This year, one of our vendors, Davey Tree Care, is utilizing a new system to administer the pesticide that we feel will do an excellent job of striking the pest while greatly reducing any chances of harming non target organisms, including people and pets, on our campus.  This system is called ArborJet and uses a pressurized cannister to push the insecticide into the cambium layer of the tree allowing the trees' own trans-evaporation processes to then move the product up the trunk and into the smaller branches and twigs where the scale is feeding.  This is a much more direct application of the product than a soil drench to the roots of the tree.  None of the product is disbursed into the surrounding environment and therefore cannot likely be contacted by non targeted or beneficial insects.  Only the insects that puncture the trees and feed are subject to the insecticide.  Most any insect feeding on the trees juices or foliage is not considered beneficial to the landscape.


Working within Integrated Pest Management practices means that in addition to using this pesticide, we will continue to practice other forms of plant health care for these trees, as well.  This will take the form of continued dead wood removal from the canopy, small amounts of structural pruning, and supplemental watering.  The sanitation of the dead wood is especially important in elms in order to lower the attraction of the bark beetles which can vector the Dutch Elm Disease.


The following photos show the insecticide being administered by a professional crew from Davey Tree Care Co. contracted to work on our campus.

Small holes are drilled into the outer layers of the tree and the injectors applied.

Then a pressurized cannister delivers the amount of material needed to treat the tree.  The amount of product needed is determined by the trees' Diameter at Breast Height.

We are hopeful that these trunk injections will help to turn the corner on contolling damage to our historic elm trees from this very resilient pest.

-Vince

Big Day

Well after almost two years of work in design and securing funding, today was a big step towards getting the Williams Village Raw Water system up and running. The new pump station was delivered today and set in place.

This station, when it comes online later this summer, will feed the irrigation water to the Williams Village complex. This new system will further the use of our Ditch Water rights and remove the usage of domestic water for irrigation at Williams Village. Currently the installation of mainlines and the pond are underway. This system has been designed a lot like the other raw water systems at CU-Boulder with a ditch delivery system, a pond, pump station and new raw water mainline.

The difference with this system compared to the others on main campus is this system has been designed to tie into the existing domestic irrigation systems. The design of the new system was rather challenging. It was tedious trying to make sure to pick up all of the small stand alone domestic systems that are used through-out Williams Village. The irrigation design company that we are using has done a great job trying to find innovative ways to get to all these locations and yet still maintain good hydraulics through the system. It is a very challenging job for sure and they have done great trying to keep everything straight and good to go.

There was a lot of help from many people to get this system funded. The major push to get this system in was to help reduce the amount of domestic water that was used for irrigation. Once this system is in and all the tie-ins have been done we expect a savings of 10-13 million gallons of domestic water. Technically, we will still be using the same amount of water but we will be using untreated ditch water instead of domestic treated water.


Once this station comes online it will be the 5th raw water pump station at CU-Boulder and will convert the last large location of domestically fed irrigation to ditch water.


Ryan

Looking back

A good thing to do once in a while is to take a breath and look back at what has been accomplished. It is very easy to get bogged down always thinking about the current list of challenges and start to feel like you are not making progress. During my recent work on the Turf Taskforce I dug through a bunch of old photos and did some comparisons on where we were, to where we are today. There are too many to show in a single post but wanted to share a few.

A good practice to get in the habit of especially in the landscape field is picture documentation. It is easy to try to remember how things look but to be able to pull up pictures from years ago helps to jog your memory. During the spring of 2002 I spent some time going around campus taking a lot of pictures of the existing conditions. Those pictures have come in handy to help realize that the work we have done is making a difference.

The look of campus in the early years of the turf program was rather dismal. After a lot of hard work by the Turf Management Team we have made great strides. As with any change, there are so many factors that play a role such as funding, understanding, but most of all patience. Mother nature has been known to take her time with certain things and growing a healthy ecosystem is not a quick turn around. We are almost 10 years into the program and we still have a long ways to go. Honestly, we may never reach the end, change happens very frequently here on campus and along with that change comes landscape impacts.

A challenge we have is preventing frustration from grounds staff. After seeing an area get turned around and brought up to a level where we are very proud there tends to be some type of construction that makes an impact to that area. This must be looked at as a challenge and a chance to make improvements. It is a chance to prove our skills and more importantly learn new ways to deal with these impacts. There is no class in Turfgrass School to deal with some of the things we are faced with and it is very interesting to think of new ways to deal with impacts.

We tend to laugh sometimes at how bored we would be if we went to a place where everything stays the same for years on end:-)

Ryan

The only constant is change.

As most of you may have seen, the Coors Events Center has been under construction for the new Basketball/Volleyball Practice Facility. Along with construction always comes a little bit of destruction of existing landscape. This is not always a bad thing, by consistently working to upgrade buildings and infrastructure on campus we help to prevent becoming stagnant and work towards continuous imporovement. At a previous employer I learned a saying that seems to fit perfectly, " You have to crack some eggs to make an omelet." I constantly remind myself of this during construction projects.


Many other locations where landscape is installed there tends to not be much in the way of constant construction or change. When they designed the irrigation system 20 years ago they had no idea where buildings would be constructed or how funding would ultimately change those master plan ideas. Sometimes with those changes come major impacts to the irrigation delivery system. I consider major portions of the delivery system to be 4" mainlines and larger.


Recently during the later stages of the practice facility design it was determined that there needed to be an area which would allow large semi-trucks to be able to back into the new loading dock. A relocation of the existing 6" mainline would have to be undertaken.

In the above picture you will see the 6" PVC mainline. Since this is a change in direction there needs to be concrete poured behind it to prevent it from moving. This is known as a "kicker" and must be poured up against virgin soil to make sure that it stays in place. The "kicker" is technically called a thrust block and is used to handle a phenomenon called "Water Hammer." The best way to describe what water hammer is to talk about the banging noises you may hear in old houses as you quickly shut of the faucet. The hammer is actually the force of the water rapidly stopping, because as with many things, once the water is in motion there is a certain amount of force behind it in motion. To have it stopped suddenly or change direction suddenly it will tend to apply forces which must be counteracted. In a home situation this hammer is normally not of sufficient force to cause a break in the pipe. However with large pipes the forces are easily great enough to cause breaks in the pipe.

In this picture you can see the actual pipe fitting  prior to the plastic and concrete being applied. Also in this picture you will notice some control wires. These are the wires that run from the irrigation clock to the individual zones and allows for the operation. Relocating the mainline itself is not too much of a problem, it is pretty straight forward.

However, the main issue comes with control wires. In the ground the control wires are just that, wires. But each individual wire goes to a station and is associated with a designated station in the controller and also the Network 8000 computer. The real challenge comes during the operation of the stations from the computer, each station has its own identity in the Network 8000 and along with that identity is the amount of heads on that station, the type of heads, the amount of water those heads put out, etc. As with any computer system it is only as good as the information you put in it, so if a station is not put back in the correct sequence it may run that station thinking it is a rotor zone but is incorrectly hooked to a pop up zone. Pop up zones generally run anywhere from 5-10 minutes during a cycle where as rotors can run up to 45 minutes, obviously there are going to be some serious flooding concerns if those stations end up running for that long.


We work extremely hard with contractors to make sure they understand this risk and take all necessary measures to iensure that there are not mistakes during this portion of the job. Of course once things are buried it becomes extrememly difficult to make repairs to the wire and thus we do extensive testing before the pipe is buried to make 100% sure everything is correct.


Ryan