moss

Moss on Upper Putting Green
(double click for enlarged image)

One problem we have at KGC that is becoming more common on golf courses is the growth of moss on putting greens. Moss is a primitive plant that is able to photosynthesize similar to regular, everyday plants but has some significant differences from plants it that it lacks roots and a vascular system. Moss, especially the species that is well adapted to putting greens, is very tolerant of drying out and is capable of remaining viable after 2 years of dessication (i.e. it will survive without water for that length of time).

Maintenance practices used on a modern golf course such as low height of cut, low fertility and sand top dressing all contribute to moss invading a putting green. Include environmental factors such as poor surface drainage and low light conditions and moss will find it easy to spread. Few chemical strategies are available for effective moss control. Most selective pesticides usually are required to be transported within a host to be effective. The lack of a vascular system in moss make this impossible. A non-selective herbicide is just that non-selective...it kills all plants which is not very useful when controlling moss on putting greens. Most moss control treatments act to stress the moss more than the surrounding turf. If moss has a weak spot it is its susceptibility to certain metals such as mercury, copper, silver, iron, and lead. In Canada (I think) iron sulphate and copper hydroxide are the only "metal" products sold for moss control.

We are fortunate since we only have moss on one area on one practice putting green and it hasn't reached epidemic proportions. We are trying to control moss by applying diluted baking soda directly to the moss. The unfortunate side effect is the phytotoxicity displayed by the turf.

Brown areas are the phytoxic spots


Close up of spots with moss in the middle

These spots are the reason for this post. They appear within one day of spraying baking soda and make the green look a lot worse off than it is.

As an interesting aside: I am, technically, "breaking the law". Any product applied to pests as a form of control is classified as a pesticide. Since baking soda is not registered as a moss control product by the PMRA (see 7/21/2010 post) in Canada I cannot legal apply it to control moss, hence the "breaking the law" statement. Any product sold to control pest has to be registered with the PMRA as a pesticide and has to have a registration number. That includes products labelled as "environmentally friendly".
I can go on and on about pesticides and perception which, I guess, is the other reason I bring this up now. We are entering that part of the season when we are applying pesticides in preparation for winter disease prevention. When applying such products we follow label recommendation with respect to PPE (Personal Protective Equipment) which usually means spray suits, gloves, face mask, and sometimes a respirator. Those items are more a precaution for the applicator since the applicator is handling the undiluted product directly when mixing in the spray tank. The somewhat hypersensitive environment that exist today around the use of pesticides makes everyone nervous when they see an applicator wearing appropriate PPE. Everyday, common place precautions like washing your hands before you eat, drink, or smoke(!?!) are a good practice to get into whenever you come in from the outside. Somehow a discussion of moss has resulted in me getting on my pesticide soap box. I'll quit now.

River Watch

September 24th

Wow! Was that a non-issue. I kinda feel like Chicken Little but if I'm going be wrong about anything let it always be this. Obviously, the rain has been a bonus as the water level at the river is as high as it was in early August. The rain and slower growth will most likely mean there is very little water use for the rest of the year so it looks like we dodged the no water bullet for 2010

Disease in the Fall

Its been a quite awhile since the last post and despite my initial comments that I would only post if something "was going" the reality is a lot has been going on I just haven't budgeted my time correctly. That been said I hope to be able to keep everybody informed on what we do this time of year so the underlying theme for most of the next couple posts will be fall and winter preparation.

This is one of the best times of the year for maintenance. The turf is changing its growth habit which means a little less mowing and less irrigation----especially this year. The cooler nights (something which has occurred all year and I suspect is one of the most important reason for course conditions this season) and shorter days help signal the turf to enter a second growth phase that is similar but smaller to the earlier growth phase in the late spring/early summer. You may have notice that certain weeds such as dandelions appear this time of year and that also relates to the improved conditions for cool season plant growth.

The change in weather also brings about conditions that encourage some turf disease. One disease I have already referenced early this year is Fusarium. (see "Week of May" 23 post for pictures and information). Another disease that is pretty common in the fall is called Anthracnose. It can appear as a foliar blight (occurring during the hot summer months) or as a basal crown rot (occurring throughout the season). Usually conditions such as low height of cut, low nitrogen fertility, and any aggressive mechanical damaging process (i.e. a deep verti-cut that cuts stolons or roots) encourage disease development. Here at KGC we see it every year at the end of August/ beginning of September.

Anthracnose infect Poa

It is best to treat this disease with preventative applications of fungicide since once it takes a foot hold it can cause severe damage that can lead to loss of turf. The tricky part is deciding when to apply a preventative application so as not to waste it. With limited fungicides registered in Canada and the threat of resistance developing within a fungal population to a particular chemical I am always hopeful that I can combine treatments into one application that will have a multitude of effects. Because of limited fungicide selection, treating a summer disease with a chemical that is also used for an over wintering disease is one possible way, through development of resistance, to limited a fungicides usefulness and length of service. This year saw a fair amount of Anthracnose throughout the golf course and as a result we had to go with the higher fungicide label rates to slow the spread on the greens. As a general rule, we will apply at least 4 treatments to the greens as a way of limiting development of any winter turf diseases. The last one is the trickiest since you want to time it just before the first permanent snow fall to get the best control. Continual snow/melt/snow/melt etc., etc. will lessen the fungicide efficacy and may result in having to apply another unplanned treatment. It does sound like the end of the world, however, many fungicides also don't recommend applying on frozen turf which is a pretty common occurrence here at KGC in November and December.

River Watch

September 10

No real change. So that is good.