Back to work today after a nice mini-break down at St David’s, Pembrokeshire and as so often is the case, as soon as you get home the weather improves !!! Good news on the weather front though as we are in for a typical early September run of weather, that is stable, high pressure, courtesy of an elevated jet stream (see image right) that took a hike up north over the weekend and looks set to stay there for the next two weeks….Yesterday was such a beautiful day here, lovely temperatures, sunshine and clouds and it seemed the air was full of insects and butterflies.
Indeed I had my annual visit from this guy, that looks like a Hummingbird in the air, but it’s actually a moth, the Hummingbird Hawkhead Moth, a migrant from France that’s visiting our shores every summer in ever-increasing numbers. Like most Butterflies and Moths they seem to love Buddleia and it nipped around mine for a good 10 minutes….smart
Onto the weather and matters turf….
General Weather Forecast
It may not seem like it looking out of the window today, (it’s raining here and very overcast) but we are in for a nice spell of weather after we get Monday out of the way. So today we’re seeing a weather front move south-east over the southern half of the U.K (/). it’s already cleared Ireland and Scotland and here you’ll should be seeing the sun. For the rest of us it’ll sink slowly south and east through the day so if it’s not with you yet, it will be in the south-east of England. Once it moves through we’ll all see some sunshine and in that warmth, temperatures will pick up to high teens, maybe even topping 20°C in some places. Winds will be light and westerly / north-westerly in nature.
By Tuesday that rain front has moved off to the continent, so that means all areas of the U.K and Ireland will be dry with variable amounts of cloud cover and light winds, though they’ll be easterly in nature for the immediate future. Temperatures will sit in the high teens, maybe a little higher if the sun comes out for any length of time and it’ll be just fine and dandy, pity we all have to work really :(…Scotland will sit a few degrees lower than the south of England due to more cloud cover through the week in general.
Wednesday sees a similar picture, perhaps with more in the way of sunshine, so temperatures up a degree or so on the early part of the week. Winds will be light and easterly and again the prognosis is dry everywhere…
Thursday may sees even less in the way of cloud cover so temperatures pushing into the low twenties during the afternoon and it’ll feel well pleasant. Maybe only the west coast of Ireland will sit slightly cooler and cloud cover persists here during the day, heavy enough possibly for some missly drizzle. Temperatures should be up in the twenties if you have sunshine, maybe 4-5°C lower if you have cloud cover.
Closing out the week we have more of the same, dry, warm, even hot by the afternoon with temperatures peaking in the low twenties I think in some areas on Friday. Winds will be light to moderate and maybe shifting round slightly to the north through Thursday / Friday. There’s also a risk of some showers being triggered off by the high temperatures, particularly over South Wales on Friday.
The upcoming weekend looks settled and dry with warm temperatures in light winds. There’s some disagreement in the weather models, how much cloud cover we will get, but if it’s overcast that’ll peg things back somewhat temperature-wise and that cloud may bring with it a risk of rain on Sunday, particularly in the morning.
As you can see from the animated Unisys GIF above, we have high pressure very much in charge so that means stable, dry conditions, warm during the day and perhaps foggy and dewy in the morning. Next week looks like following a similar pattern to this week then, but maybe at the very end of the week there’s a chance that the high pressure will get moved out of the way by low pressure which is stacking up to the west of Ireland. That may mean a wet and unsettled weekend for the middle of the month.
As we approach the autumn, disease and increasing disease pressure is never far from our minds, but after a wet and dismal last week where a number of you reported active Fusarium (Microdochium nivale) , I think we will see a drop in disease pressure over the coming 10-14 days because surfaces will dry out nicely.
If you have got active disease you have a decision to make, either hit it with a systemic+contact tankmix early or apply a straight contact fungicide. Now that decision will depend on where your course is located because we know that Microdochium pressure in Ireland and Scotland starts earlier than it does in the south of the U.K. In the latter I always look at the 6 weeks from the start of October to the middle of November as the key period to minimise Microdchium populations in the sward, whereas in Ireland and Scotland I think it’s more like the start of September through till temperatures drop in November. (earlier in Scotland normally)
My preference would be to use a straight contact at the moment (not a protectant mind) and keep your systemic powder dry for later in the month.
Anthracnose Recovery Measures
This year has seen a lot of areas affected by Anthracnose, not just greens, but collars and approaches as well, so we can see that the pressure for this particular disease has been high, but why ?
Well firstly we have to understand Anthracnose as a disease and that it can manifest itself in two different forms – Foliar Blight and Basal Rot. I stand to be corrected, but I feel that the Foliar Blight version of the disease is the one we tend to see more of after the plant has experienced stress, particularly prolonged high air temperatures during the day and night.
When I first came into this industry (1989 be jaysus) Anthracnose was a winter-only disease, always showing up as a basal rot and typically from November onwards. It wasn’t until really post -2000 that we started to see more and more Anthracnose during the summer months. I remember attending a GCSAA lecture given by Bruce Clark in 2012 and he typically covers the top-10 diseases in the U.S. He made a point of remarking that 15 years ago, Anthracnose didn’t make the top 10 diseases (As reported by Superintendents over there), but now it’s top 3 and has been for the last 10 years or so.
Over here I think we tend to see both Foliar Blight and Basal Rot occurring in the same sward, the difference between the two is that the Foliar Blight is held to attack the older leaves first and then spread to newer growth, whereas the Basal Rot goes for the base of the crown every time. Recently I took some pictures with a small microscope of Anthracnose-affected turf and you can clearly see the fruiting structures of the disease (Acervuli) on the leaf tissue….
Once you see the type of symptoms shown above on your turf, your perspective should be focussed on remedial action because curative control of Anthracnose using a fungicide is largely ineffective in my books, it’s like a mobile speed trap by the side of the road, once you see it, it’s too late to do anything about it, well it is with my driving / riding…. Sure a chemical application may ‘ring fence’ the affected areas, but the turf you see yellowing off won’t instantly get better overnight.
So getting back to the first question ;
“Why have I got Anthracnose this year when I’ve done nothing different from other years ?”…
For sure the main driver for Anthracnose is climatic conditions and the optimum ones are high daily air temperatures that put the plant (Normally Poa annua) under stress followed by high rainfall or heavy irrigation events that saturate the turf surface and encourage spore germination and fungal movement from plant to plant.
So looking at July and August we can see we’ve had ideal conditions for Anthracnose.
Firstly, we had a hot July with two pronounced periods of plant stress, these are highlighted in dotted red circles on the green growth potential line on the stats from Long Ashton Golf Club (Cheers James)…
It wasn’t only high temperatures, it was windy as well and that means high daily moisture loss from the turf canopy by evapotranspiration (E.T). You can see from the graph below using stats from The Oxfordshire (Cheers Sean) that we had 14 days when the E.T > 4.5mm during July 2014, (shown as red columns) which in my books signifies plant stress and requires hand watering to control moisture loss.
The total E.T figure for July was 135mm compared to a more normal 100mm, so July was 35% harder on the grass plant than normal in terms of regulating moisture uptake and loss.
Secondly in some areas we also had high rainfall events in July that saturated the turf surface. In others we had very little rainfall which meant increased reliance on irrigation and thereby hangs the rub…
I think irrigation is one of the least-understood management practices because a lot of golf course managers don’t measure (in mm) how much water they’re putting on, how much they need to put on (they don’t measure E.T rates) and how variable moisture levels are across a green surface.
A harsh statement maybe, and I accept some of this is down to under-investment in resources, particularly manpower because you need more bodies if you want to hand water, you need a weather station to monitor E.T accurately and you need money to be able to afford a moisture meter.
A direct consequence of this is that a lot of golf greens receive too much water from their irrigation systems during hot, dry conditions and because we know that water will not be distributed evenly across a golf green, some areas will sit wetter, some areas drier. Without the factility to measure this, we are weeing into a strong prevailing air flow and creating an ideal environment for disease, particularly fungal pathogens that are influenced by leaf and soil moisture levels.
So the answer to the question is mainly climatic conditions, but we also influence Anthracnose by how we maintain greens. I’ve covered irrigation / watering, but there’s also nutrition and without a doubt it’s one of the best ways of preventing Anthracnose, that of tightening application frequencies during and after stress periods and thereby ensuring the plant doesn’t slip into a nutrient level trough, i.e it’s weak and not growing sufficiently well enough to overcome the threat of disease. All the work has shown that regular, light foliar applications are the best way of achieving this, as effective as putting down a preventative fungicide it seems and certainly a lot cheaper ! If this isn’t workable, then a light rate granular fertiliser can work wonders during this period.
Chasing low N numbers is an admirable cause some would say, but not at the expense of turf quality. I’m sure all your golfers and secretary managers/ committees, etc aren’t going to shake you by the hand when you say you’ve applied less than 100kg / N / hectare, but your sward is full of thin areas because you have been hit by Anthracnose as a consequence. Too little N is just as bad as too much N and none more so than when we talk about this disease…
Once you have Anthracnose your focus should be on getting surfaces back as quickly as possible and that means remedial work.
Firstly we need to take the stress off the grass plant, but in our climate because we tend to see Anthracnose after the stress the biggest part of this has already take place in that the weather has changed (cooled down), however there are other changes you can do ;
As commented on earlier, we often see Basal Rot Anthracnose as well as Foliar Blight, so trying to encourage the damaged plant to initiate new roots is a good idea. The first part of this is spiking, hollow coring, solid tining to encourage root development and sometimes if the weather plays ball, this in itself will go a long way to turning things round, remember although Anthracnose is a pain of a disease, the fact we are dealing with Poa means we have one of the greatest surviviors in the plant kingdom as an ally. The pic right shows a Poa plant initiating new root development from a damaged crown after an attack of Anthracnose Basal Rot….
If you feel the need to overseed areas, hollow coring beforehand is without doubt the best way because you’re dropping the seed into a hole filled with new rootzone material and without the barrier of organic matter present which oftens provides a barrier to the newly developing grass seed root system. The plant is also slightly below the canopy so the cutting height is actually higher. Some people look at Anthracnose as an ideal opportunity to introduce more Bentgrass (by way of overseeding) into the sward.
Upping the nutrition, lowering or omitting PGR usage until you have a consistent turf canopy across the green and frequent spiking and topdressing are all conducive to aiding recovery, especially the topdressing part because it encourages tillering.
A number of people have commented to me over the years that they feel Anthracnose is a ‘wound-related’ disease and that summer topdressing encourages its presence. Research work has failed to show this, nor has there been proven a correlation between increased rolling and Anthracnose, in fact the latter has been the case because a firmer surface means a more consistent (bench to turf) cutting height with less sinking down of the mower into the turf canopy (resulting in a lower overall cutting height and more plant stress)
You’ll note I haven’t spent much time on fungicide applications and that’s because I think the most effective fungicide applications for Anthracnose are preventative in nature, rather than curative, I’m really not sure in my own mind if a post-Anthracnose application achieves anything apart from putting a hole in your budget and peace of mind.
A good piece on Anthracnose research is readable here….
Other consequences of the summer
After a hot, dry summer we often see an increase in moss on golf greens and this is because the moss will outcompete the grass on areas that dry out, such as mounds, noses, ridges of greens. Silver Thread Moss is one of the worst for this and will withstand a much higher degree of dessication than the grass around it. I’ve already had reports of moss populations increasing and I expect this to continue.
Monthly GDD update
Continuing our look at how conditions have been, Wendy has kindly collated the GDD info for August and you can see as a month it fared poorly to other years, in fact it’s the lowest GDD total for August since we’ve been recording GDD information and reflects that it was a cool and disappointing month in general. 🙁
Headland Weathercheck Problem
Some of you set up on Meteoblue’s weather forecasting system that we run under the name Weathercheck have been having some issues with the RainNow part of the forecast, sometimes it is showing, sometimes it isn’t. We are trying with Meteoblue’s assistance to get to the bottom of this, but if you are still experiencing problems can you please email firstname.lastname@example.org with your internet browser name and version and if possible a screenshot, that would be most useful, cheers….Paul will liaise with you on this.
Ok bit of a mammoth blog for this week, so now back to the daily grind…
All the best.
If you want more background on this disease, there’s an excellent Podcast by Karl Danneberger available here