Wednesday, 27 July 2016

Diseasey as hell out here. Summer Disease update.

"Summertime and the livin' is easy"

We are now half-way through the summer and have still not required a broadcast traditional fungicide application on greens. To say it has been easy would be a lie. It has been a roller coaster of disease activity but for the most part I have been able to keep everything in check and the golfers here have been enjoying some of the best conditions in years.

The weather this summer has been very diseasey. What I mean by this is lots of cool and wet followed by hot and humid. Last year it was hot and dry which made it relatively easy to manage disease. This year I have seen it all. Dollar spot, brown patch, fusarium, and even thatch collapse! Even crazier is that I have seen it all at the same time.
Dollar spot, fusarium, and brown patch in one photo on tees. This is "diseasey"
For the past 4 years I thought I had dollar spot beat. That was until this year when I started seeing dollar spot on my greens. It came on very slow and I was able to count the individual spots to track it's spread. I started spot spraying the spots with propiconazole to see what that would do. On my 8th green the dollar spot seemed like it was heading out of control. It had more infection sites than the rest of my greens combined and I was almost ready to put out a broadcast spray to stop the explosion of disease.
Etiolation in areas where no TE has been applied. Diseasey
Then I started thinking. Why am I having dollar spot issues this year and not the previous 3 or 4 years? What is different about this year? I am rolling more than ever before and rolling definitely helps reduce dollar spot. My nitrogen rates are at their peak for the season so that should also help. There are no moisture issues. What is going on?

Then I started thinking about how rolling reduces dollar spot. Apparently, from what I've read, rolling increases the microbial population in the soil and this has a negative effect on the dollar spot fungus. There is even a bio-fungicide called Rhapsody ASO that uses bascillus subtillus to help control the disease. All of this got me thinking about the soil and what I was applying to it that might be throwing it off balance.
Diseasey as hell
Manganese! A few months ago I saw some patches on my 8th green that I thought might be take all patch. My 8th green is mostly bentgrass now and my manganese levels were quite low. They recommend keeping the soil levels around 30ppm to keep take-all-patch at bay. I was at 4ppm. So I started applying manganese to try and bring the levels up. A week and half later after I started weekly 5kg apps of manganese monohydrate I noticed my first spots of dollar spots show up.
FML thatch collapse
Time went on and the "take-all" didn't go away. The patches were dark green and when I shared a pic on twitter it was suggested that maybe it was thatch collapse. I stepped on the patch and was horrified to find that it was sunken. I was even more horrified to now notice that all those dark green patches weren't just poorly set plugs, they were more of the disease. We will see how that goes in the coming months and years. Another disease I am lucky to gain some experience with.

more thatch collapse
Back to dollar spot. I had a hunch that manganese might be impacting the soil microorganisms negatively so I stopped applying it in my weekly fertilizer applications because I didn't have a take-all problem. In the past week the dollar spot has slowed down and I am now no longer worried about it. I have some Rhapsody in storage so I might put some of it out if things flare up again but I am optimistic I won't need to do this.
Hole 8 has the majority of the disease infection this year.
It is cool to see this happen with dollar spot. Just when you think you have a disease beat you get it again, and are afforded the opportunity to learn something new about it so that you can make better disease management decisions in the future. I am learning that dollar spot is highly reliant on a healthy soil (whatever that means) and maybe if we can limit products that could have a negative impact on the soil during times of dollar spot activity, we might be able to manage it with rolling, urea, and maybe even phosphite and silica and other biological controls. I really like the idea of letting the plant's natural defenses (beefed up with ISR and SAR products) and soil microorganisms doing the work as there is much less headache as far as resistance is concerned (it's also way cheaper).

I'm also learning what things might impact the soil microbe population balance (assuming I am correct about the soil biology crap). With disease like dollar spot that seem to be impacted by the soil biology (and controlled by natural organisms) it really makes you think. I also noticed that my moss-killing disease also disappeared this year around the same time that the dollar spot came on. I wonder if the two are connected at all?

I also came across an interesting quote in a turfdisease.org post. "There is evidence that hydrogen dioxide can aggravate a dollar spot outbreak by reducing natural competitors to the Sclerotinia homoeocarpa mycelium." If hydrogen dioxide can do this then other products could possibly do the same thing. Yep, I bet this is what was happening on my greens this summer and no, I haven't found any written evidence of this online yet. Purely speculation so don't take my word for it.

It also makes me think about other disease that I have had issues with like fusarium and cyanobacteria. These diseases seem to be controlled by applying "harsh" products to the plant leaves. By harsh I mean things like iron, sulfur or other metals like copper. Maybe the key is to limit these types of products when dollar spot is active or at least apply them in quantities that limit their impact on the soil. So far this year I have absolutely no cyanobacteria despite the wet weather. I bet this is because of my use of manganese monohydrate which has sulfur in it.

It's all a big balancing act and it is super cool to try and find that "balance" that everyone is always talking about. I'm not sure if balance involves bombarding the soil with "beneficial" organisms or if it just means limiting the negative impacts of products that we apply and allowing the soil to find that balance for itself.

The less corrective traditional pesticides I use the more I think I might maybe possibly be seeing how things all work. Seemingly innocuous things like potassium can have huge impacts on disease if applied at the wrong (or right) time. Too much during fusarium activity can = bad, too litte during anthracnose activity = bad, not enough in soil (below MLSN) = bad. I think we still have a ton to learn about how we can optimize our fertilizer applications to limit the negative consequences and maximize their benefits to plant health.

I still have dollar spot on my tees and fairways and they only receive nitrogen and some potassium on my tees. This tells me that it's not just a "healthy soil" that is required to manage dollar spot without the intervention of traditional pesticides. Under the stresses of regular mowing and traffic found on golf courses you still need to give the upper hand to the turf whether is is by rolling or by applying phosphite or other ISR products or beneficial bacteria. I am also not 100% certain I am in the clear on my greens either. The disease spread has slowed  and stopped in some cases but the worst time of the year for dollar spot is yet to come so who knows how that will go?

It brings me back to my thoughts about the problems with organic golf. It is so limiting that I think it shuts a lot of doors for opportunities to learn. With the safety net of good traditional pesticide products to save your ass when things go wrong, we can push things a bit further to try and learn how do do it with minimal intervention. Right now I'm in uncharted territory. Five months without a broadcast traditional fungicide application and active dollar spot on all greens. If I didn't have some sort of safety net I would be freaking out.

In my case I have needed 20ml of propiconazole to spot spray the dollar spot on my greens. Did this even help? Is dollar spot spread by mowers like fusarium might be? I don't know but either way it was useful for me to count new spots as it was easy to see which spots had already been sprayed in the past. The act of counting disease really helps me understand that actual disease activity and has allowed me to really put off "emotional sprays" like I used to do when I had less information about how much disease there really was out there.

For a while there in May I was a bit worried I would have no disease this year. A little bit of disease is a good thing for how I operate. It keeps you grounded and tells you a lot about what is happening in the environment. No disease, no story, no improvement in your understanding of how it all works. That's how I see it anyway. What a hippy eh?

The summer's not over yet so fingers crossed that I can keep the good times going until the difficult transition to fall brings back the ultimate challenge of fusarium. I can't wait to try some things this fall. The tough times are always an opportunity to make improvements.




Saturday, 9 July 2016

Why Use Growth Potential to Schedule Fertilizer Applications?

This is a very similar post to one I did 4 years ago but instead of theorizing about the benefits of Growth Potential I am speaking with some experience.

The growth potential fertilizer model isn't something that has been studied in depth by science (what's taking them so long) but that doesn't make it wrong. For this reason there are some people that are still quite skeptical of using a model such as this to schedule nitrogen fertilizer applications. While I'm obviously no scientist, I do now have almost 4 seasons under my belt and can share some of my initial reasons for making the switch and some of the reasons I continue to use it as a base for my fertilizer applications.

Way back when I used to schedule my fertilizer based on the typical cool season growth curve similar to the one in the diagram below.
We've all seen this. Big growth jump in the spring, a slowdown in the summer and a big growth jump again in the fall. I would then apply most of my fertilizer during the times of maximum growth. How many people still fertilize this way?

What if I told you that you are already fertilizing based on growth potential. That is exactly what the above curve represents. If you apply more fertilizer at times when the grass is theoretically growing the most (spring and fall according to the above diagram) then you are doing exactly what the growth potential theory helps you do

Here's the problem. That is the growth potential curve for places just north of the transition zone. For anyone in Canada (unless your name is Ryan and you grow grass in Osoyoos or anywhere in the Okanagan really.) this really isn't how grass grows in our climate.

Here is what the cool season growth curve looks like in my climate.

So by using the growth potential formula (see climate appraisal form from PACE Turf) we can calculate the potential for grass to grow in our particular climate. As you can see we get very little growth in the winter spring and fall and a lot of growth in the Summer. It rarely gets hot enough to limit cool season growth here in the summer months.

So if you believe and use the first cool season growth potential curve and understand that every course and climate is slightly different then you will probably really like the growth potential formula.

Now the idea of fertilizing like this is to give the plant what it needs when it needs it most so that it can grow healthy and produce the playing surfaces that we desire. Back in 2012 I made a bunch of predictions and theories and it is interesting to look back over the last 4 years and see what really has changed for the better on my course.

Predictability

This past April I wrote a post explaining how I have never had such good control of growth rates on my course. This control has continued right into mid June. Despite the roller coaster weather we have been having, the growth rates remain more or less in control. We haven't had a single "growth explosion" this year and clippings clumping together are non-existent. Does the following clipping yield from my greens look like a familiar curve?



Helps with disease

One of the main themes of my blog over the years has been me sharing my experience trying to fight turf disease and weeds without pesticides. Part of the success I have been having over the years making meaningful reductions in pesticide use has been a result of using growth potential to schedule my fertilizer applications.

I've always known that fertilizer has to have some impact on turf disease, I wrote a post about how N could be the most overlooked nutrient in IPM plans. Obviously it's not just me, one of my mentors early on in my career always used to say "don't feed the disease" referring to fusarium patch and nitrogen fertilizer.

For me, fusarium is the big issue from September through June and Anthracnose and Dollar spot are problems in July- September.

In general, Fusarium is made worse by higher nitrogen fertilizer rates and Anthracnose and Dollar spot are made worse by low nitrogen fertilizer rates. The only problem with most of these studies is that they look at annual N rates and not the rates of N applied only during active disease cycles. I apply 12gN/m2 (2.5lbs of N/1000sq ft) each year but 80% of that is applied in the Summer. Knowing when these diseases caused problems on my course and looking at the first generic growth potential curve for cool season graph and now you can see the problem.
If you base N rates on this chart in my climate you are making fusarium and dollar spot and anthracnose worse. Do the opposite and these disease aren't as bad.

Back before 2012 I was over-fertilizing during times of fusarium activity and under-fertilizing during times of dollar spot and anthracnose activity. Simply by switching the timing of my nitrogen fertilizer applications to a growth potential curve that is fine tuned to my particular golf course I have had much more successes managing these diseases without traditional pesticides.

Amount of N applied to greens based off of GP formula.

It's not hippy dippy idealism, it's just common sense, stuff that we already know and stuff that has been proven by science. So even if you don't agree that using the growth potential curve developed by Pace Turf is a good idea then you surely must agree that it's probably a good idea to apply fertilizer in quantities that reduce the impact of the most troublesome turfgrass pests at your site while keeping playing conditions optimal. Guess what? It turns out (for me anyway) that GP helps me fertilize exactly in a way that limits the impacts of these diseases on my turf and I'm not getting any complaints about how the greens play.


The past few winters I have had less and less issues fighting fusarium patch on my course. This past winter was downright easy despite receiving almost 50" of rain and having warmer than normal weather. I have now continued into July still without the need for a traditional pesticide to control fusarium. It isn't because of my tolerance for "garbage dump conditions" (see the comments in this post), the greens are actually more or less completely clean of any disease. I have never seen my greens with so little disease, during such adverse weather conditions (wet and cool June) without the use of traditional pesticides. I have a few thoughts about this but that's a topic for an upcoming post.

When it comes to Dollar spot I haven't needed a traditional pesticide to control this troublesome turf pest since 2013 (coincidentally the first full year I implemented GP and.....knock on wood haha).

Will it work for you? Maybe, but there are also a ton of other things that I do to help with this disease, again, a topic for another upcoming post and the topic of this recent post with a killer comment section. I know you can't control dollar spot with nitrogen alone, but if you are having problems with this disease, compare your nitrogen rates to those that the GP formula suggests you apply. Are you over, under? Maybe this can help you reduce the impact of this major disease on your course.

Anthracnose. Last year I had some issues with this disease but didn't require the use of traditional pesticides. Typically anthracnose is made worse under low nitrogen and potassium rates. Last year was the first year that I halved my nitrogen rates on my greens and I was also getting fancy with potassium and MLSN guidelines. This is probably why I saw anthracnose for the first time in my career last year. This year the plan is to apply potassium 1:1 with nitrogen (to ensure that K stays above MLSN guidelines) during the summer which will see the majority of my annual K applied during periods of high anthracnose damage potential. Stay tuned to see how that goes!



So for me, at my course, growth potential fertilizer has inadvertently made a huge impact on my need for traditional pesticides and has allowed me to produce some of the best conditions of my career despite a 30% reduction in cost and EIQ of my overall pest control budget (traditional and ISR pest control products included).

Less thatch, better drainage

I have less data on this but over the past few years we went from having a lot of chronic wet, thatchy spots on our fairways to having almost none. This despite going through a wet winter with over 50" of rain an extremely wet June and July so far. Typically during rain events that we have recently been experiencing it would take days for the course to dry out, disease would explode everywhere and the course would be a wet soggy mess. This year we are out playing with carts on the fairways a few hours after receiving an inch of rain. Also, we don't aerate fairways. I wonder if this has to do with having a growth rate that matches the optimum temperature for biology in general for my climate. Are the "munchy bugs" in the soil consuming the organic matter produced by the grass at a similar rate that it is produced? It looks that way.

Too good to be true? I would say so but wow, I am seeing some cool things here.

Is there a better more predictable way to fertilize grass? I haven't found one.

When I ask those who say using GP is bad how they would prefer to fertilize grass I am left with, "use your eyes and apply nitrogen to keep the colour acceptable." The problem with this is that this is reactive fertilizer management, it is a step backwards in my opinion. Applying fertilizer AFTER you notice a decline in colour or growth or continuing to apply fertilizer without knowing if it's too much. The goal of GP is to have you applying the right amount of nitrogen for the time of the year so that you don't see any change in colour or disease pressure or clipping yield.

Running nitrogen too low or too high for the time of year can have consequences. More disease, turf thinning, excessive thatch and soft conditions, the need for excessive aeration, more mowing, more fuel consumption, you name it.  If the grass is growing faster it needs more food is how I like to think about it. Without adequate fertilizer during periods of optimum growth you can inadvertently stress your grass leading to bad things.


For me I like to use fertilizer to make the plant able to handle stress, combat disease while growing as slow as possible before problems arise. Growth potential helps me do that in a much more consistent way.

If you aren't yet using the growth potential formula to schedule your nitrogen applications, I highly suggest that you at least do the calculations and compare what you are doing to the theoretical amount you should be applying. Maybe you are spot on, or maybe it might help you understand some of the issues you are having out on the course.

Happy grass killing!

Friday, 8 July 2016

No disease WTF?

I have been putting this post off for a while now. It seems that whenever I post about my success with disease management on my course I immediately get bit in the ass. Karma or something..
Who cares about the crooked flag when the greens are disease free?
So for this reason I am hesitant to write this post sharing my experience over the past 4 months battling turf disease on my course. Here's the problem, there isn't any. Maybe if I type it really small it won't be heard by mother nature and she will spare me in the coming months.

Here's the thing, since my last traditional pesticide application on Feb 22nd, there has been almost no disease on my greens. I'm the most surprised person really because never in my entire career have I seen something even close to this. Every day I venture out to inspect my greens I am expecting chaos, total destruction, disease apocalypse, but to my disbelief the greens continue to be more or less disease free. Aside from a few minor dollar spot outbreaks (requiring no action on my part) I have seen no disease on my greens this spring and summer.

Back in 2013 I had a similar story but it was quickly followed up with a reality check. The main difference here is that I'm not using Civitas and that it is on all my greens and the control I am seeing is unparalleled. Even when I was regularly using traditional pesticides I didn't have this good or consistent of control. This is despite coming out of a super wet winter, super hot and dry spring, and wet and cool summer. The weather has been all over the map yet the greens remain disease free. I'm really saying this too much and am now sure to find my greens covered in disease tomorrow morning. Damn.

So what am I doing that is resulting in the lack of disease? Well the honest answer is that I am doing everything. I am using every trick I have in the bag to keep my greens disease free. It's all part of my IPM plan.

Culturally I am mowing less, rolling more, watering early and following growth potential almost to the T.
Fusarium is still there, lurking just outside of where I manage for it.

Before I go into chemical controls I want to be clear in case any pro pesticide fanatics are reading this. I'm not saying that what I am using is controlling the disease. ISR products help the plant control the disease as does fertilizer, water and mowing practices. So go ahead and "rat me out" and see what that accomplishes.

Chemically I have continued my use of phosphite. This May I tried a new produce to me that contained silica. Oh boy, here comes the snake oil sales pitch. Nope, no sales pitch, you can figure out what to buy on your own.
Even the "stressed" poa during seed head production is disease free. WTF?
At first I was skeptical but was intrigued when John Dempsey said it might have merit. For the most part turf scientist dismiss the effects of silica on turfgrass health but John's tweet was the first time I had heard someone who studies ISR products on turf say something positive about it.

I did some digging online and found some interesting research articles showing silica's impact on other plants. All plants are different but hmmmm, maybe there's something here?

fusariumy weather,
So beginning in late April I starting using a phosphite produce that contained silica. And then I went through May and June without the need for a traditional pesticide application. This is something that has never happened at my course since at least 2007 (I don't have records going back any further). Add to this that we also went March and April without a traditional fungicide application and WOW.

Now this is despite the weather being very "fusariumy" out. In the past with only phosphite I had always seen some fusarium activity although it was highly suppressed. This year, nothing, absolutely nothing. Not a single spec on any of my greens. WTF!

Here's my fertilizer record showing exactly what and when I applied everything this year. All numbers are KG/100m2. Last traditional pesticide app was on Feb 22nd.
DateNPKSCaMgFePhosphiteMnSi
1/19/20160.0230.000.000.010.000.000.000.040.000.000
2/14/20160.0160.000.000.020.000.000.000.010.000.000
3/6/20160.0000.000.030.000.000.000.000.040.000.000
3/29/20160.0210.000.040.030.000.000.010.040.000.000
4/13/20160.0360.000.050.030.000.000.000.040.000.000
4/26/20160.0180.000.010.020.000.000.010.040.000.001
5/2/20160.0580.000.030.040.000.000.000.010.000.001
5/10/20160.0380.000.010.020.000.000.000.010.000.001
5/17/20160.0400.000.010.020.000.000.000.010.000.001
5/23/20160.0400.000.010.020.000.000.000.010.000.001
5/31/20160.0400.000.040.040.000.000.000.010.000.001
6/7/20160.0470.000.050.040.000.000.000.010.000.001
6/13/20160.0310.000.040.030.000.000.000.010.000.001
6/20/20160.0540.000.060.030.000.000.000.010.000.001
6/28/20160.0690.000.080.050.000.000.000.010.040.001
7/4/20160.0550.000.060.040.000.000.000.010.040.001

So now I start to wonder. Are phosphite and silica working together? Do they compliment each other in their ISR modes of action? Am I just seeing things? Will there be negative consequences of this approach? This sure as hell is better than covering your grass in gross green pigment.

As far as my pesticide use goal setting and tracking goes I am right on track for a repeat of last year's big reduction. This is promising because if something can't be reliably repeated it's probably not worth doing. So far so good. Just to be clear the following table includes all phosphite and silica products in the cost. I could not calculate the EIQ of the silica so it is not included in the calculation. This is for 0.4ha (~1acre) of greens.

Sustainability MetricYTD Total CostGoalPercent of Goal UsedYTDProgressDays ahead/behind goalPercent of YTDNext App Max
Cost Fusarium$1,400.71$3,000.0046.69%51.51%4.82%1890.65%$144.49
Cost Dollar Spot$0.00$0.0051.51%51.51%1880.00%$0.00
Total Cost$1,400.71$3,000.0046.69%51.51%4.82%1890.65%$144.49
Fusarium EIQ293.01560.0052.32%51.51%-0.82%-3101.58%-4.57
Dollar Spot EIQ0.001.000.00%51.51%51.51%1880.00%0.52
Total EIQ293.01561.0052.23%51.51%-0.72%-3101.40%-4.05

I plan to continue to use silica and phosphite through the summer and into the fall/winter. The next big test will be late August/early September as I have never made it through this period without a traditional pesticide application for fusarium patch. Fingers crossed and trying not to get too confident.

I would highly suggest that you give silica a try, a least to see if it makes a difference to your disease management strategy. This year it was the only thing I changed and I noticed a big difference. Remember, I'm not just relying on silica and phosphite and they are part of my overall IPM strategy to manage for fusarium patch on my greens.

So there, I said it, but now I'm done talking about it in case Mother Nature hears and tries to teach me a lesson about dead grass.

But then what am I going to talk about if there's no disease..... I'm sure it'll be back, it always is!