My first blog of 2019 and a Happy New Year to you all…
So we endured a really mild and a really dull Christmas period with precious little sunshine or frost. With temperatures up in the teens on occasion you can’t blame nature for being a bit confused with spring bulbs well on their way to flowering.
The October-born Hedgehog litter that visits my garden have kept on feeding, taking advantage of this mild spell to fatten up for when winter will inevitably start. The advice is that Hedgehogs need to be around 600gms to last the hibernation process and as you can see from the image below, some of my lot have reached 575gms, so nearly there.
And that’s a good job because winter is due to start this week and I expect them to hibernate 2-3 days before as if they always seem to know it is around the corner.
The Christmas period and early January was characterised by mild weather conditions, nothing unusual in that really, but actually there was.
Mild weather in the winter is usually the result of Atlantic low pressure systems. pushing in windy, wet and mild air. This time the heat came from an Atlantic high pressure system and that in my books is highly unusual. Normally high pressure in the winter means cold, dry, sunny and frosty with mist or fog but that isn’t what we got. This weather system brought in mild air, lots of cloud, no wind and very little else. This of course had huge ramifications for disease activity which I will cover later in the blog.
You may remember my last blog of 2018, the meteorologists were predicting a Sudden Stratospheric Warming (SSW) during December and indeed it occurred on December 29th. Last year it took just over 2 weeks for the SSW to affect the wind direction in the troposphere and turn it to easterly, the rest is history. This one is on a slower burn and in fact only 43% of SSW events actually result in a changing of the weather patterns that affect you or I.
So will this SSW event pan out as another Beast from the east scenario ?
It now looks like the picture above will change subtly over the next 10 days with the trough pattern edging further west and that could bring winter our way. So let’s put some detail on it…
General Weather Picture
So Monday starts with a mainly dull picture across the U.K and Ireland, although sitting here I can see some breaks in the cloud as the sun is rising. There are some wintry showers around over The North East but these will edge out into The North Sea through the morning. After that the scene is set on another dull day with light to moderate winds and precious little sunshine except maybe for the north-east of Scotland. Temperature-wise, we are looking at 8-10°C.
Tuesday sees rain edge into north-west Scotland overnight and push slowly southwards so by dawn it’s into Central Scotland and The Borders. South and west of this sees a re-run of Monday with a calm but dull start to the day for England, Wales and Ireland. As we move through the morning that rain over Scotland drops south into northern England and at the same time intensifies over north-west Scotland, falling as wintry showers over elevation. So for most another ‘dull as dishwater’ day with similar temperatures to Monday albeit with a fresh westerly wind.
Overnight into Wednesday and we see that rain front over Scotland push into north-west Ireland and move eastwards across Ireland during the small hours edging into West Wales, the north-west of England and Scotland by dawn. This band of rain and wintry showers will edge eastwards brightening up behind it across Ireland as it does, reaching The Midlands by lunchtime and central / eastern areas by the afternoon. If anything the mix of rain and wintry showers tends to intensify over north-west England / The Lake District through the latter part of the day with other areas brightening up as skies clear. Slightly cooler through Wednesday as the wind swings more northerly across Scotland and introduces cooler air but this change won’t become apparent further south till Thursday. Here a westerly wind will prevail but with clearing skies temperatures will drop to around freezing for Thursday morning.
So Thursday starts a good bit cooler for most with a ground frost in places. A much brighter start to the day than we have been used to as well with most of those wintry showers dying out overnight and moving off into The North Sea. So cool but bright on Thursday with a strong to moderate north-westerly wind now in situ. As we progress through the morning, we see cloud cover push in from the west for Ireland as another Atlantic low pressure front approaches. This cloud cover pushes east across Wales and central areas as we approach dusk, but the east should stay relatively clear and bright all day. By dusk the rain that threatened is now into the west of Ireland and will push eastwards overnight falling as wintry showers at elevation. So a much cooler feel to Thursday with that north-westerly wind direction, expect temperatures around 4-5°C at best, quite a drop since the start of the week.
Overnight into Friday that rain front over Ireland pushes eastwards reaching The South West and South Wales by the small hours and falling as sleet over Dartmoor and The Black Mountains. By dawn the mix of rain, sleet and snow is placed diagonally from Connacht down to south-east Munster and extending across South Wales into The South West. East and north of this front, we start the day dull, cold and dry over the majority of England and Scotland. As we progress through Friday morning the front edges along the south coast of England and across Wales, clearing Ireland from the west as it does. The skies will also clear across Scotland for the 2nd half of Friday to leave a cold, but clear end to the day. As we approach Friday afternoon / evening this mix of moisture has edged further eastwards into The Midlands and south-east of England, falling as sleet across elevation. We may also see that mix of wintry showers sit across east Leinster and bring a Christmas Pudding dusting to The Sugar Loaf and the mountains of Wicklow 🙂 Another cold one with temperatures barely breaking 6°C all day with the wind having switched round to north-easterly / easterly.
So what’s the outlook for the weekend look like ?
Well we may still have some of that overnight mix of rain and sleet / wintry showers sitting over the southern half of England first off but this will soon move off into The North Sea to leave a bright but cold Saturday and indeed Sunday for most. So dry, bright and cold would be my prognosis once we have lost that early Saturday front. The wind will be strongly from the north on Saturday so they’ll be a pronounced windchill but as we go into Sunday, the winds will drop and it’ll feel a little nicer because of this. Still cold though with frosts likely on both Saturday and Sunday nights.
So this is where life gets interesting…
So next week looks like starting off pretty calm and settled after a not-so-bad weekend for many with dull conditions and a north-westerly wind for Monday. It should be pretty dry though. As we go through Tuesday the winds begin to ramp up as a very intense low pressure system threatens to swing down through the 2nd half of the day bringing some strong winds and heavy rain / wintry showers to Wales and England in particular. This continues through Wednesday with some very strong north-westerly winds and heavy wintry showers especially over Scotland initially. Much colder air is likely to push south to all areas for the 2nd half of Wednesday with snow more likely across all areas and a bitter windchill because of that wind strength and direction. Thursday at this stage looks like a continuation of those strong north-westerly winds but less intense wintry showers rather than a concentrated band of snow.
Now a big caveat, things can change for sure and this deep low could just roll over the top of us into Europe as it has done so far this winter, but this one looks different and if it occurs could mark the start of a longer-term trough pattern for the U.K and Ireland. If this is the case we will see much colder air push down with a higher likelihood of snow and it may last.
Since this is my first blog of 2019 it would be pertinent to look at how the year ended up GDD-wise after such a year of extremes. The yearly summary from my Netatmo Weather Station kind of says it all though, 36.5°C highest temperature, just 438mm of rain all year and a -7.7°C low !
December 2018 – GDD Summary – Thame Location
So looking at December in isolation, the Thame location came in with a total GDD of 37, which is around about average, nothing special either way. The yearly total GDD of 2055 is only just shy of 2017’s total, despite finishing March such a long way behind. Is there any pattern to this ?
I was chatting this through with Mr Kirby of Syngenta and we surmised that there wasn’t a great deal of consistency in terms of a general GDD trend year-on-year, but that’s hardly surprising when you think this is just a 9-year snap shot. We also know that during some years we got SSW events that dealt us a cold winter and spring and others we didn’t.
Interestingly I charted out the GDD totals from May to December which effectively removes any influence of SSW (as they tend to occur and affect our weather from Jan onwards)
I think I can see the beginning of a pattern with our GDD increasing by 3-5% over the last 4 years from May to December. (Glenn???)
The devil is in the detail as they say because these totals hide some really big agronomic effects such as ;
Prolonged hot and dry periods with record summer temperatures and E.T levels. This has left some areas of the country still deficient in rainfall as we tip-toe into the following year with a threat of reduced abstraction and water restrictions likely if we don’t get a top up before summer starts again. You only have to look at the number of new housing estates springing up all over the country to know that the demand for water is only going one way and for sure the water companies are nervously looking at their water table figures with a view to Summer 2019.
Not for all parts of the country that’s for sure, but for some I think….
Our soil moisture deficit going into the autumn of 2018 was 2x the previous year and rather than just being a figure, I think some of the effects of the summer heat weren’t really appreciated until afterwards. For sure we saw a dry-down of not only surface organic matter but also deep into the rootzone profile below our fairways, rough and outfield. This has made soil profiles (not just the surface layer) hydrophobic and many autumn over-seeding efforts were I think thwarted by a dry surface fibre layer and also a dry soil underneath.
Last but definitely not least we have Microdochium activity which I think was the worst we have endured. Not in terms of peaks of activity in October but more so what followed during December and into January. I will look at this in more detail further down the blog and open up a bit of a discussion on just where we are going as a industry..
GDD & Rainfall Summary – December 2018 – UK Locations
Well one of most variable graphs I’ve done for a while in terms of rainfall and GDD totals. As with some of my past graphs, the south-west of England picks up the wettest weather with nearly 10″ (247.2mm) recorded for our Devon location (my sympathies Pete) and similar amounts for Wales as well I’m told. You can see the localised effect of rainfall as well with 108.2 recorded for Central Birmingham and 53.6mm recorded for Market Harborough less than 50 miles away.
From a GDD perspective, a lot of variability here as well ranging from 24.3 in Fife (though similarly low in York as well) right up to 69.4 down in Guildford (it must be the warming effect of the M25!) . On a serious note though that’s approximately 3x the growth for the south of England vs. the east of Scotland.
GDD & Rainfall Summary – December 2018 – Irish Locations
Just like the south-west of England, the south-west of Ireland picks up the highest rainfall total (278.6mm) by a long way, but you can see the spread of rain across Ireland was extremely variable. 3x the rainfall for Cork compared to Dublin ! The south and west of Ireland again came out with higher rainfall totals as it has done all year.
GDD-wise, again significant variability with Valentia the highest at 120.4 (that’s nearly double the highest total from a U.K location) right down to Cavan and Claremorris, which came in at 51.1 and 52.7 respectively. Low for Ireland but much higher than many U.K locations for the same period.
Microdochium nivale – Disease Pressure – Autumn / Winter 2018 / 19
Without a doubt the autumn winter period has been challenging in terms of keeping a clean sward from a Microdochium perspective. The advent of a mild Atlantic high pressure appearing in December and lasting through to January has been a real game changer in my mind because rather than just seeing activity on existing disease scars, we also saw very aggressive new activity late in the year.
This level of disease activity is set against a background of reduced fungicide options and the first season without Iprodione as a curative control. Normally when we saw activity late in the year we would reach for this active ingredient in front of any other because of its local penetrant action and the ability to knock back new disease.
With this option missing on the Chemsafe shelf there was no way of stopping new infection unless you were fortunate enough to have applied a systemic fungicide period to the Christmas period. I say this because spray windows leading up to Christmas were few and far between, it was very wet and also windy. Even then I have had reports of some of these applications not achieving control of new disease activity such was the extent of the disease pressure.
Existing scars showed significant movement as well…You may remember in a previous blog I marked the outside of some disease scars with dots of white paint when I was doing a trial.
Two such scars are shown below ;
The disease scars shown below aren’t the exact same ones but were marked the same way on the 27th November.
The pictures were taken on the 17th December (before the worst outbreak but after significant pressure in the 1st part of December)
You can clearly see the previously-affected area in the centre of the patch showing signs of recovery but the white dots no longer mark the edge of the affected area as the patch has grown visibly outwards. I’ll update with a January image in due course…
So why was the Christmas period so bad for Microdochium ? (and also Red Thread it has to be said..).
Well blame it all on that Atlantic high pressure system because it gave us mild, humid air and no wind, so night and day temperatures varied little and the leaf stayed wet for long periods of time.
The graph above shows the period from December 20th through to January 13th and looks at maximum and minimum air temperature as well as humidity.
The period of weather that really did it for disease pressure started on the 26th December and carried right through to the 29th December unabated. What characterised this period so markedly was a night and day temperature > 6°C and 100% humidity for the whole period.
So in other words, the plant leaf sat wet for 72 hours and provided an ideal environment for Microdochium nivale. The air temperature maintained above 6°C day and night through this period which I now know allowed for significant development of Microdochium nivale.
I say ‘now know’ because I have just completed a population growth curve study with 2 different Microdochium nivale isolates, one from the U.K and one from Germany (to keep neutrality in the Brexit debate 🙂 ) looking at fungal growth vs. air temperature.
I will present the findings in my talk at BTME next week but suffice to say this pathogen has a healthy growth rate at 5°C….:(
Microdochium nivale – Where do we go from here ?
So we experienced very high disease pressure probably at a time when it is fair to say we didn’t expect it. It also emanated from a weather pattern that was unusual in my experience for the end of December / start of January.
Some of the clubs that had weathered the worst up until this time were caught out and sustained high disease scarring even though they may have applied 3-4 preventative fungicides prior to Christmas leading some to question whether they were actually better off for having applied 4 fungicides ?
For me without a doubt the degree of scarring would have been so much higher without keeping the disease pathogen population lower on the run up to this period. I know this because I’ve seen the untreated areas in trials at the S.T.R.I, in my own field trials and where some end-users have attempted to go through this period without a fungicide. That said I am not dismissive of the sentiment behind such thinking. We know modern-day fungicides contain far less A.I than their past counterparts and as stated earlier we no longer have the luxury of a contact-curative so we aren’t by anyone’s admission in the same boat as we once were.
It is also unfair to point the finger solely at pesticides because now more than ever we have to have an effective overall IPM program in place. It’s no longer good enough to pay lip service to this statement because climate and legislation have tipped the balance firmly in favour of the pathogen.
All is far from lost but it does mean we have to pay more attention to surface organic matter, cultivar mix, dew dispersal and non-pesticidal treatments than maybe we once did when we had an effective safety net of pesticides at our disposal.
It is going to take some education as well within clubs because the average Joe isn’t used to disease scarring and we need to explain to management and members alike that we have to implement an effective IPM program. That means aeration, overseeding and everything else we know is necessary but also some fine tuning of tolerance to a level of disease scarring because of the reasons I have already highlighted.
Disease on drier, more open greens vs. wetter ones…
Now here’s a thing…
Plenty of you have fed back to me that you have seen consistently worse disease on your more open, free-draining greens and precious little on your soil based, wetter greens. Logic would suggest this should be the other way round surely ?
Sometimes it isn’t though and it has got everyone I think scratching their collective heads a little..
I have discussed it before as a noted phenomenon, so what may be the cause behind this disease pattern ?
Well firstly greens that have a higher sand content will hold less water and will usually (if the sand is the correct particle size) hold more air than their equivalent soil based counterpart. Now we know that gas heats up and cools down quicker than liquid so one theory of mine is that a higher sand content green will heat up faster than a soil green and this will encourage a higher pathogen population (because we know that the speed of mycelium growth and spore germination of Microdochium nivale both increase with temperature)
This is my SWAG answer (Scientific wild arsed guess – copyright Dr James Beard) but to me its logicial, do I have proof ? No.
My second theory relates to the survivability of Microdochium nivale spores with respect to temperature and moisture. We know from research conducted in agriculture on Microdochium nivale populations in Winter Wheat that spore survival is poor during periods of cool, wet conditions and high during drier winters, regardless of temperature. So I am wondering whether a soil green that sits wet during the autumn / winter will actually have a lower level of viable spores than a sand / soil or USGA-spec rootzone ?
Please note, this is a separate discussion from Microdochium nivale mycelium, i.e the behaviour of the fungus itself once the spore has germinated. Here we know plant leaf wetness encourages growth of the pathogen, period. One reason why I favour the spore viability theory is that I tend to see the phenomenon of more aggressive Microdochium on drier, more open-aspect greens once we reach the spring and it begins to warm up. The fact we have seen it now on some courses is I think because of the unusually warm weather patterns I have discussed earlier.
Ok that’s it for this week, I have a lot more to say but as usual I’m going to run out of time. I hope to see some of you at Harrogate next week and yes I know I’m always yapping on the stand but I’ll do my best to say hello and have time 🙂
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All the best for the coming year.