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  • Writer's pictureMark Hunt

September 25th, 2023

Hi All,

I spent a lovely day at Sywell Airfield yesterday at their annual Piston & Props show, a must for any petrolhead. It is an ecliptic mix of racing motorcycles, carts and cars and also various clubs show vintage and historic motorcycles. I took along my 1989 Honda Hawk for a run out a day chatting to other motorcycle enthusiasts. There are sometimes WWI and WWII aircraft as well.

One vehicle that took mine (and the crowds eye) was a custom modified Wheel Horse Garden Tractor Mower that had a 1,000cc Honda motorcycle engine fitted and wheelie bars. It does a 1/4 mile in around 11 seconds and was hitting 140 mph on the runway.

So if you are looking at getting your rough under control quickly, there are options....😊

it was interesting listening to the commentator and some of the people I bumped into bemoaning the accuracy of the weather forecast. Saturday was reasonably nice and Sunday was warm and drizzly until the afternoon. The problem is when you get low cloud in the summer that often falls as drizzle, it is very difficult to distinguish between the two, even on rain radar technology. It is also very difficult to forecast. Meteoblue got it pretty right I have to say.

The weather at the moment is very difficult to forecast beyond 5 days with GFS outputs alternating between a succession of deep Atlantic low pressure systems and the odd high pressure peak pattern in-between. With some golf courses receiving over 50mm of rain in 3-4 days last week, we need some good wind strength and E.T.

The problem is with rapidly shortening day length we are losing sun hours and drying time. In the summer a typical E.T day will evaporate 3-4mm of moisture so over a week, we can lose 28mm of moisture and in some weeks, much more. This time of year, a week's worth of E.T is nearer 10-15mm and so the soil takes much longer to dry down from a rainfall event.

General Weather Situation

So we start this week with low pressure still in charge which means we will be unsettled and windy. It's a bit of a Celtic divide though because the west and north will pick up the brunt of the associated rainfall and wind gusts, with Ireland, Scotland and Wales very much in the firing line. The north and north west of England also.

It is of course Hurricane season and these intense low pressure systems that we are seeing are remnants of Hurricanes that have previously affected the U.S.

Storm Agnes

Mid-week, this week we have an intense low pressure system crossing in from the south west of Ireland and currently it is predicted to cross Ireland and the U.K mid-week. The Met Office / Met Éireann and the Royal Netherlands Meteorological Institute has named it Storm Agnes (named after Agnes Mary Clerke, the Irish Astronomer and Science writer):and issued a yellow warning for certain areas of the Ireland and the U.K, you can read about it here.

Incidentally, the 2023/24 storm season started on September 1st, so it is a new set of names and no Storm Mark I see, bah bah grumpbag.......

You can see the GFS graphic below (for Wed 27th September) courtesy of and in particular the tightly-packed isobars across Ireland, the north / south west of England, Wales and the west coast of Scotland.

So Monday to Wednesday we see very mild southerly / south westerly winds across the U.K & Ireland with significant rainfall I am afraid for Ireland, Wales, the north west of England and Scotland. The peak of the storm will be on Wednesday so that means very strong winds and heavy rain for the areas I have already detailed. Further south we won't be completely dry but will see a sunshine and showers pattern of weather with the heaviest rain pushing through on Wednesday as that low pressure systems passes across the UK. The airstream will be mild so expect 18-20°C across the south of the U.K and 15-17°C across the more unsettled areas.

We don't have much of a gap between the next one as this will cross Ireland and the north of the U.K on Thursday. So a very wet outlook this week for Ireland and Scotland with heavy rain, strong winds and with the ground already saturated, flooding is likely I am afraid. Again a north-south divide because the southern half of the U.K will be less affected by this second low pressure aside for strong winds and showers.

As we approach the end of the week a ridge of high pressure will push up from southern Europe and that will introduce a calming effect on the weather, just in time for the weekend as the GFS graphic shows above for Saturday 30th September. So a nice autumnal weekend is on the cards for the southern half of the U.K, but unfortunately another Atlantic low pressure will push up rain into Ireland, the north west / north of England and Scotland over the 2nd part of the weekend accompanied by strengthening southerly / south westerly wind.

Weather Outlook

So we start next week with a low pressure system pushing in strong westerly winds across the U.K and Ireland but we also have a ridge of high pressure sitting south west of England. The current prediction is that this will hold sway for the first half of next week but thereafter things like getting a bit fruity.

Below is the projected GIF for next Thursday 05-10-23.

I don't think I can ever remember seeing 2 low pressure systems, one sitting on top of the other pushing in to north and south of the U.K & Ireland. Quite bizarre.

So the second half of next week looks like being wet and cooler as the wind swings round to the north west, so feeling chillier and much more unsettled at the end of next week / weekend as it stands currently.

Agronomic Notes

Reproduced courtesy of Syngenta Turf & Landscape - UK & Ireland (

A new fungicide active for the U.K Golf Industry

Well, it has been a bit of time since I wrote that text and I know for the company behind it as well, Syngenta. Whether you subscribe to the use of fungicides or not, the very fact that we are still getting new arrivals is for me is a big plus point because undoubtedly the cards are stacked against us disease pressure-wise due to changing climatic conditions. The cards are also stacked against companies trying to develop new fungicides from a legislative perspective.

Now I have been a bit out of the product development game for nearly two years, so first up, have a look at the official Syngenta documentation here

I did some work with this product when I had a trials and research hat on in my Headland Amenity days and I can tell you it marks a significant introduction of a new effective fungicide active, Solatenol in combination with Difenoconazole. This active is an SDHI (Succinate dehydrogenase inhibitor) and in my experience when combined with Difenoconazole, highly effective against the plethora of diseases that we most often bump up against.

To quote Syngenta's information "Results from over 70 trials throughout Europe have shown the highly effective performance against a full range of key turf diseases, including Microdochium nivale, Anthracnose, Dollar spot and Take-all. Trials had also shown good effect on Fairy Ring"

With a depleted range of fungicide actives now available to greenkeepers and groundsman alike, it is great to see this product now fully available. I can sense how many hoops they will have had to jump through to get approval in our changing legislative environment since Brexit, so well done Syngenta.

It isn't just the fact we have a new fungicide active in combination with an effective existing one. It allows more options from a rotational perspective which is key to avoiding the development of resistance in the future. Particularly when we look at Dollar Spot which is definitely the disease on the move in the last few years both in terms of increasing the geographical range of turf that it affects and moving from outfield to fine turf. One to keep an eye on if you haven't seen it at your facility yet.

In my early days in this industry (early nineties and before most of you reading this were born probably :) ), Dollar Spot was a disease that affected bowling greens across the south and south west of England only. It was also prevalent on the continent across Holland, Germany and Switzerland for example. Nowadays it is one of the most aggressive diseases we encounter and is widespread across all areas of the U.K & Ireland, Scandinavia, central and southern Europe.

The driver in my mind is the frequency of more humid, warmer air, later into the year and its role in both dew formation and fungal development.

GDD stats - August 2023

Usually I do this in the early part of the month when I look back at the previous months GDD, G.P and rainfall stats across the U.K and Ireland but with my plethoria (word of the day eh) of holidays, I am late in getting the stats together, my apologies....

GDD stats - August 2023 - The Oxfordshire, Thame, U.K

So above is the monthly and yearly cumulative GDD data from The Oxfordshire showing August 2023 came in with a total GDD of 334 (using 6°C as a base temperature) which is 20% lower than the high of 2022. It reflects the cooler nature of the weather of course over this summer once the June heatwave broke. Now you might think why then were we out cutting like mad and having to work doubly hard to maintain good green speed if the GDD was lower than last year. Well as you'll see from the combined Growth Potential and rainfall data later in this blog, the difference was this summer we had temperature AND rainfall, last summer we had the temperature but not the rainfall. You'll also see the difference in the Growth Potential specifically.

The total for y.t.d 2023 came in at 1409 till the end of August which is also down on last year but still toward the upper end of cumulative GDD's we have measured since we started this in 2005 (geez I am old). Up to the end of June we were ahead of prior year, but with the cooler July and August, we have dropped back a little.

U.K Locations - Growth Potential and Rainfall - U.K Locations

So the above shows that the monthly Growth Potential for the U.K ranged between 26.31-29.52 with an average of 27.86. Bearing in mind there are 31 days in August, the total theoretical Growth Potential for the month is 31 (31 days x optimum G.P of 1.0).

So an average of 27.86/31 = ⁓90%. With the consistent rainfall through the month of August that kept outfield areas growing, a growth rate of 90% of optimum compounded to make life interesting from a maintenance perspective.

Irish Locations - Growth Potential and Rainfall - U.K Locations

The Irish stats paint a fairly brutal picture of two very high rainfall months on the bounce coupled with warm temperatures. I haven't been to Ireland for awhile now but I can only imagine that means really hard job controlling outfield growth, getting machinery out on the course, managing clippings and the like.

The monthly G.P for August 2023 ranged from 26.5 - 28.4, with an average of ~27.4, that's very similar to the figure for the U.K and comes in at 88% of optimum growth for the month of August. Although there is the usual west-east divide across Ireland from a rainfall perspective, the east still got > 85mm during the month, so it was a wet August everywhere. it will also have been a high disease pressure month because with that rain comes humidity and of course long periods of plant leaf wetness.

Although we have more heavy rainfall on the way, the saving grace is that we also have plenty of wind as well which will help dry down and discourage disease development trying to finish on a positive note like 🙂

OK, that's it for this week, all the best.

Mark Hunt

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