Hi All,

Another topsy-turvy weather week passes with some cracking thunderstorms and rain coupled with heat and humidity. You could see the cloud formations building as we went through the day as updrafts funnelled hot air from the ground and pulled in cool air and precipitation. I snapped this one over Hallaton in Leicestershire whilst out for a yomp enjoying the beautiful countryside. As usual though when you get this type of rainfall formation it was very hit and miss.

Things looks to settle down this week as we lose some of the heat and humidity courtesy of the return of our old friend, the north-east wind and cloud cover.

General Weather Situation

So Monday starts off as a drab, dull one across many areas as that switch round from west to north-east wind rolls into play. Here in The Midlands, I can accurately report it occurred at 7.20 p.m. last night as I was fishing the evening rise at Eyebrook (which had only just started) and then the wind swung round completely, the temperature dropped 5°C in a fraction and the fish promptly shut up shop 🙁

With this wind in situ, it’ll be the familiar picture of eastern coasts staying dull and the best of the brightness out west across Wales, The South West and Ireland. Maybe not today for The South West though as we see a risk of rain spreading into this area through the morning together with some drizzle and light rain for south-west Scotland. Elsewhere that cloud will keep the mockers on the temperature for most of the day occasionally allowing the sun to break through across South Wales and most of Ireland. So temperature-wise, a bit of a drop from the mid-twenties of the weekend down to mid-high teens for areas of the U.K under that cloud and lifting to low twenties where you see the sun, so more to the west and for Ireland.

Tuesday sees much of the same, plenty of cloud around initially but this will break from the west to give long spells of sunny weather and pleasant temperatures for most areas. Ireland looks to see some rain showers through the day, more down the middle of the country and probably accompanied by some thunder as well if the heat gets up. By the afternoon, that cloud cover should be confined to eastern coasts and the north of Ireland as well allowing temperatures to rise nicely into the high teens, maybe touching twenty degrees for Ireland. Winds remaining light to moderate and from the north-east.

Wednesday sees almost a carbon-copy re-run of Tuesday, starting off dull with plenty of cloud cover and then the sun burns this off from the west allowing temperatures to rise significantly. We may hang onto that cloud cover again across The North East and Western Scotland but otherwise dry and sunny is the forecast. For Ireland we see the familiar pattern of a warm, dry sunny start to the day triggering off some thunderstorms later in the afternoon and into the evening. These are more likely to be western-orientated. The wind will be as is, north east and light to moderate. Temperature-wise, 18 – 22°C depending on cloud cover.

Thursday sees another predominantly dry day but with a thicker cloud mass over the east of the U.K. So a better chance of seeing the sun and some decent temperatures across Ireland, Wales, The South West and west coast of the U.K. Again that cloud cover may be stubborn to clear from the east of the country and we may see a re-occurrence of those thunderstorms across the west of Ireland possibly. Similar temperatures to Wednesday, 18 – 22°C depending on cloud cover with that north-east wind keeping things pegged down on the pleasant side of warm.

Closing the week out on Friday we have pretty much an identical day to Thursday, cloud cover across the east, clearer and warmer across the west, you get the picture by now I am sure. The only potential fly in the ointment may be the risk of continental rain drifting into the south-east of England late on Friday evening. Similar temperatures to Thursday, 18 – 22°C depending on cloud cover. Kind of a boring weather week really.

So the outlook for the weekend is more of the same I think but we have a Bay of Biscay low pressure close by as we go through the weekend so there’s a chance that may feed up some rain into the south-east later in the weekend. We will see. We may see the wind change from north-east to easterlies which will tickle temperatures up a little but at the same time may increase the risk of rain drifting over from the continent. Otherwise it looks dry, sunny and pleasantly warm on the whole with temperatures in the high-teens / low twenties depending on cloud cover. No complaining here.

Weather Outlook

So next week looks very similar to this week, well at least the start of it does but we still have the low pressure lingering south of us to potentially muddy the waters somewhat. At this stage the projections are for that low to stay south of us and that means any rain may just be along the south coast of England, Ireland. So a weak high pressure stays in charge for the early part of the week and things look to stay settled until Thursday that is when all the models point to a change in the weather to a more Atlantic-orientated air stream which will push in at the end of next week bringing strong winds, cooler temperatures and rain I think to most areas starting with the north and west first and then moving southwards in time for the weekend.

Agronomic Notes

Normally being the first blog of the month I do a monthly GDD summary but that’ll have to wait till next week when I have some more GDD summaries in from around and about the U.K.

Disease Pressure

Over the last week we have seen quite significant disease pressure on many turf surfaces prompted by rainfall, high temperatures and above all, high humidity. The chart above shows a readout for May from my location and you can clearly see the 100% humidity peaks on the 24th, 25th, 26th, 27th, 30th and 31st.

Looking at surfaces last week there was a good amount of Microdochium nivale apparent, not just on greens but also collars, complexes, approaches and even fairways. Fortunately with high daily Growth Potential as well, this was being grown out as fast as it was appearing and already you could see new growth in the affected areas, especially off green.

The chart above from The Oxfordshire (thanks Sean) reinforces the end of May period as being the main culprit behind increased disease pressure with the 26th, 27th and 28th of May representing continual high humidity.

There were other factors driving this disease development including very mild overnight temperatures with the minimum temperature at my location exceeding 13°C  from the 28th May onwards right through to last night when we didn’t drop below 14.9°C at all. Dew formation as well was very heavy on some mornings leading to extended periods of leaf wetness.

So we have a witches brew of high overnight temperature, humidity and dew and that will always drive disease.


Other diseases kicking about have been Superficial Fairy Rings and some Etiolated Growth, particularly on the clean up strip cut on greens.

We have come to a bit of a dead end with this disease of late in terms of finding a way forward. In the U.S it is pinned on a bacterial (rather than a fungal) infection of the grass plant but in all the samples I have taken we have failed to either observe the bacterial streaming synonymous with Etiolated Growth or isolate any one of the identified causal bacterial pathogens.

You can kind of look at this both a positive and a negative really because if we had identified a bacterial pathogen there isn’t anything we could do about it other than nipping down to the doctors for some antibiotics and plastering Streptomycin on 🙂

I can’t understand why it shows up so clearly on the clean up strip cut either, right on the margin between the green and the collar cut ? Ideas anyone ?

Anthracnose Trigger

Last week I talked about the potential for the weather during May to have given us high enough temperatures to initiate Anthracnose Spore germination. The question is whether we also got the humidity as well to give the fungus a chance to grow on the leaf and initially infect the plant. When you look at the fact that May’s weather was so variable in terms of rainfall and also temperature it is likely that in some parts of the country we hit the required threshold values for both temperature and humidity whereas in other parts we didn’t. Scotland for example has been really warm and when I can access some local weather station information (Weather underground appears to have changed its API access so you can’t look at historical data currently) I’ll be able to determine if this area of the country may have got an early Anthracnose trigger or not.

PGR efficacy or lack of efficacy ?

I’ve had some reports of pretty poor performance from PGR’s applied lately in terms of not suppressing growth particularly well. I’m not sure if this is anything to do with the product though because when you look at the end of May, the growth level has been really high with 6 out of the last 7 days of May showing a Growth Potential > 0.9. It could just be that with a high growth rate the amount of regulation afforded by Trinexapac-ethyl hasn’t been as significant as usual.

Looking at the temperatures in May and putting them into the U.S GDD model for PGR usage, it looks to me that a greens application of TE should have lasted around 14 days no problem so I don’t think it is a case of the A.I breaking down in the plant overly-quickly.


Acelepryn Insecticide

As mentioned last week it looks like the above product from Syngenta has received Emergency Use approval in the U.K. As I understand it the rate will be 0.6 litres per ha and it will only be used as a preventative treatment. Product supplies are likely to be limited and the cost will be significant per hectare, that said I think it is excellent news for our industry and I commend Syngenta for pushing this through and giving greenkeepers and groundsmen-alike an option now for grub control depending on the area they are maintaining of course. Full details of the E.U approval and product will no doubt be available on Greencast in the future (I bet Dan’s busy writing it as we speak 🙂 ). For some background reading, you can find a link to the U.S product technical sheet here

Please bear in mind this is the U.S tech sheet and it is only provided to give you a heads up, nothing more.

Ok that’s me for this week, all the best for the coming week.

Mark Hunt