Saturday, 27 July 2013

Moss Disease

                                             



 I noticed something interesting happening to the moss on my practice green this summer. It appeared to be under attach by some sort of pathogen. I posted some pictures online when I first made the observation and had literally no feedback as to what it could be. Maybe no one had seen this on their course because they didn't have this much moss? The first time I head of the possibility of this disease was from the Superintendent at my neighbour course. He had a very slight case of this but it really wasn't that obvious and I shrugged it off as nothing. I was really surprised to see such a widespread incidence on my practice green this spring.

Today I came across a blog post from Dan Strey from Iowa State University who had made a similar observation in one of his moss studies. He found it to be Sclerotium rolfsii and likened its appearance to that of the dollar spot fungus. He noted that " It is very common in the tropics, subtropics, and other warm temperature regions. However, it is very rare to see the disease this far north. The pathogen rarely occurs when winter temperatures fall below 32˚F." This winter was very mild on the Southern Coast of Canada and this could be a reason why I am seeing this show up on my greens. Other contributing factors to this disease occurrence could be the lack of traditional fungicide treatments on this green since 2011, and the poor irrigation system which has lately been re-cycling the schedules and severely over-watering this green combined with relatively hot daytime temperatures. 

 I have sent samples off to be diagnosed but would welcome any other labs out there to check this out for curiosity sake. I think it is pretty cool and who knows, maybe it could be made into a biological moss control in the future?




Saturday, 20 July 2013

Junuary

This post is a bit late as I have been a tad busy the past few weeks moving to a new town and battling the July summer heat. June might go down as one of the most difficult months I have ever had dealing with disease and the survival of my putting greens. I had two of the worst outbreaks of Fusarium I have ever seen in my 6 years as Superintendent here. It was a stressful month to say the least but I came out of it with a few new strategies for next year. The massive failure that was June 2013 helped me fine tune my disease management strategy.

June seems to be becoming a wet month in my part of the world. Last year it was consistently wet all month long. This year it started off with a few intense rain events then got decently nice for a week or so followed by an insane week of rain (same weather event that flooded Calgary). The first week of June my original disease management approach fell apart and I was forced to go back to traditional pesticides to regain control of the fusarium. I had to put all my plans on hold (including growth potential fertility) to regain control of the situation and push recovery on the greens. As the weather dried out the recovery was quick. Just as things were getting back into decent shape we got the same rain event that flooded parts of Alberta and that's where it got really bad. The fusarium exploded as the control provided from the Iprodione applied in early June faded. I was unable to apply any corrective fungicides until 3 days after the outbreak as it was raining much to hard. Things got even worse when the weather suddenly got very hot for the July 1 long weekend. The saturated greens were inundated with golfer traffic and they were almost turned into mud. It was very disheartening to say the least. With some stroke of luck I was able to keep everything alive and the greens are now in pretty good shape.

Heavy golfer traffic on over-saturated greens = bad
Looking back and after analysing my actions for that month I have made a few observations and changes to my fusarium management plan:

The growth rates in June were out of control. I am still using Primo Maxx to regulate growth but for some reason it just wasn't performing at all. I would get great growth rate control for about 3 days followed by intense growth action! It was so bad that we had to cut 2 times a day and were still scalping. It was this injury that probably made the disease attack worse. What I think went wrong here was that the Primo I was using was no longer working as I had been nursing the same jug since 2007! I had also increased nitrogen rates to push recovery which probably only made things worse. I should probably take my own advise more seriously in the future. Needless to say I bought a new jug of Primo and the growth rates have been much more consistent since then.

The growth surges are exactly in tune with disease pressure. High growth = high disease activity
As I had so much success with my Civitas and phosphite program through the winter I had decided to keep on with it through the summer which I now see as a mistake. I was applying these products on a 3 week cycle which worked great until about mid-May. At about this time I would notice an increased disease pressure mounting on the greens starting about 2 weeks after the application. Looking back I should have taken this as a sign. Man, I am dumb sometimes! Obviously as the temperatures warm up the plant's metabolism also increases and these products are used up quicker. Since the last big outbreak I have switched back to weekly applications of both of these products along with my fertilizer applications. In the future I plan on switching to weekly applications in April when I resume my weekly fertilizer applications. I will keep the overall monthly rates the same for now with just different application intervals. If this doesn't work I might try adapting my rates to the growth potential. Light and frequent, light and frequent, light and frequent, say it with me people.

What really clued me on was an application error on the 17th of June where I forgot to put my phosphite product in my spray tank while fertilizing greens. I remembered after I had already sprayed 2 greens but thought "what's the worst that could happen?" Well I was completely shocked to see the difference this product really made to my fusarium management program. I knew it worked, just not this much!
Missed phosphite application on the left. Phosphites applied on the right.

The worst of it, I almost had a heart attack

Fluffy white death
Following the crazy fusarium outbreak the weather dried out nicely and it got hot. Four days after dealing with the fusaium I had dollar spot mycelium on my greens! I mixed in some Rhapsody ASO (bacillus subtilis) and went directly into my dollar spot management plan. I wasn't able to roll at all in June and had to wait until mid July to start back up again as it was just too wet. Since that day I haven't seen a single sign of dollar spot anywhere except for a tee box that dried up due to a faulty controller. Urea applications based on growth potential, adequate soil moisture, daily rolling, civitas and rhapsody are a winning combination for dollar spot control on Poa greens in my opinion and experience.
Are you serious? Don't even start....
Crap
I have also changed my disease management approach on my fairways this year. Last year and in years prior I was always smoked with dollar spot as I mentioned in this post last August. So instead of doing nothing I am applying urea based on growth potential and wetting agent applications every three weeks. This might be too long an interval for the summer but I will give it a try this year and see how it goes. Based on history I should start to see some dollar spot on my fairways any day now but so far they are clean.

It is months like this that I wish I had more bent in my greens. The bentgrass I had was completely untouched by the fusarium but when you have 95%+ poa and shit hits the fan you just need to grow poa! Fertilizer, water, and pesticides!

All in all I am pretty happy with the outcome of June. I was kicked in the ass but was able to come out of it in decent shape. I leaned a few lessons and should be better prepared come next year. I will also carry these lessons on into September as I once again try to fend off the fusarium as the season winds down. So far I have not been successful in making it through September without traditional pesticides so I hope the things I have learned over the past year will help me accomplish this goal. Fingers crossed!