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Hi All,

Another late blog, yes I know, but such is the way of the world at the moment, a tad hectic to say the least… 🙁

Well some of us got clattered with rain over the last four days in the form of some really heavy, localised downpours. I’ve measured 45mm over that timeframe here in Market Harborough, deep in the Welland valley, but I know barely 10 miles from here, they only had 10mm, such was the localised nature of the storms.

Some very nice thunder and lightning mixed in with that over Thursday night / Friday morning.  I lifted this image off Netweather’s lightning site archive which shows the track of lightning strikes over the U.K. last Friday and the time they occurred. You can clearly see the path of the storms…

270614Lightnin g

That big bunch of yellow crosses in the west country is around Glastonbury. Maybe it’s a coincidence, maybe not, but thunder and lightning storms tend to track along deep valleys and of course Dolly Parton was appearing around that time, need I say more… 🙂

On a serious note, if you want to see where lightning is occurring in the U.K. at any given point in time, you can click onto the Met Office ATD (Arrival Time Difference) system which logs lightning strikes and updates every 15 minutes (though there is a 15 minute delay to allow for processing). Netweather have a link to it on their site here

General Weather Situation

Ok, so how is this week looking and is that low pressure I predicted last week still on track to appear at the end of this week and provide Lewis Hamilton with a nice wet qualifying at Silverstone on Saturday? In short, yes… possibly, though the rain may have passed through by then. We have a low pressure system on the way down to us which will bring general rain across the U.K. and Ireland later in the week, more in the North than the South (because that’s where it’s coming from), but we all should see some showers from Friday onwards.

So, for Tuesday we have a dry picture across the U.K. and Ireland after that localised rain that affected Wimbledon departs stage left. Early doors some more rain is expected to move into the south-west and north-east of England where it may sit for the majority of the day, perhaps tracking inland a little to affect northern England. Elsewhere it’ll be another lovely day: warm, bright and sunny, with temperatures tipping into the low twenties. As we move into Tuesday evening that rain dies out to leave a dry picture across the U.K. and Ireland for the start of Wednesday.

Wednesday sees an about face with the wind changing from easterly to westerly and that marks the impending arrival of low pressure from the North, but fear not because Wednesday looks a cracker, lovely temperatures; sunny and warm. Later in the day a wet front, the first from that low in the North, tips into the north-west of Scotland and gives a soggy evening in the beautiful Western Isles of Scotland and Donegal (with one ‘n’ Michael, I haven’t forgotten :)).

Moving into Thursday, that rain peters out by the morning rush hour to leave a dull start for the north of the U.K. and Ireland, with some localised light showers, but still brighter in the South away from the cloud cover. That’s the way it stays for most of Thursday: bright, warm and sunny from The Midlands south, but duller, cooler and eventually wetter in the north and west of the U.K. and Ireland overnight into Friday.

So for Friday we have a pretty solid rain front pushing into Ireland and Scotland early doors and then affecting the west coast of the U.K. through Friday morning into the afternoon when it begins to move eastwards across the U.K. So by Friday evening, it spans across most of the U.K. having cleared Ireland by now. There’s a chance that the far South-East may stay dry all day, but we’ll see as this looks like a pretty solid front. There’ll be a marked temperature difference, just like on Thursday, with the South still touching 20°C, whereas the west and north will be 4-5°C lower with a brisk, north-west wind.

So how are we set for the weekend? In a word, ‘unsettled’… That rain from Friday will push south east overnight into Saturday to cover most of the U.K. So Saturday at the moment looks like starting wet for the south of the U.K. then drying out through the morning. The opposite is true for Ireland where it looks to start dry, with arriving later on Saturday in the form of blustery showers pushed along by a brisk north west wind. The boot may well be on the other foot for Sunday with a dry start for most of Scotland and Ireland, but with rain over the U.K. tracking in from the North-West down to the South-East, so it may be a soggy race for Silverstone. Oh dear! Hope Bernie doesn’t get his car stuck again… 🙁 I expect the temperature to be a good bit cooler as well for the weekend, mid-teens the order of the day in a chilly north-west wind.

Weather Outlook

So is this the end of summer? No, ’tis not… Ok it’s going to be cooler and unsettled for the weekend and the start of next week, but I expect things to improve by mid-next week, with the arrival of a warm Atlantic high pressure. The fact that it’s coming from the Atlantic means the West will benefit first from this better weather, so I expect Ireland to warm up first (for a change) from Tuesday onwards and slowly for this warmer weather to push eastwards across the U.K. for the latter part of the week. Now, at the moment, that low is set to sit over Scandinavia, so the dividing line may mean that the north and east of the U.K. stays unsettled right up to the back end of next week and cooler as well with northerly winds.

That’s the only potential fly in the ointment really, the wind direction will stay northerly, keeping things a little cooler than normally would be the case, as the high pressure on the west side of the U.K. butts up to the low pressure over Scandinavia and the wind gets squeezed down between the two. The best way to envisage it is imagine Dolly Parton’s… no, forget that 🙂

Agronomic Notes

Etiolated Growth

Back on track after a slight deviation there…. As has been my way over the last few weeks I’m going to pick one main subject to focus on and this week it’s etiolated (pronounced eti-o-lated) growth or etiolated tiller syndrome (ETS as it’s known across the pond) because no doubt we are seeing more and more of it around on managed turf surfaces.

Before I go on to talk about it I’m assuming that you’re all familar with this phenomenon of grass growth normally restricted to Poa Annua biotypes across fine and coarse turf surfaces. It’s usually more pronounced on collars and aprons, but fairways, sports pitches and the like can also show this bleached, extended/stretched grass poking up above the cutting height only hours after the area has been cut. I did a fact sheet about ETS last year which you can find here

For sure the weather is a key driver to this phenomenon because it tends to occur when we have a combination of dry, warm weather and then moisture (be that natural or irrigation). That said, a query from the field sparked my grey matter into action last week (thanks Rob) when the question was asked whether there was any link between PGR applications and ETS ?

I’m not saying there is, but something is making ETS more and more prevalent on amenity turf and I’m not 100% sure the weather is the only driver.

We know trinexapac-ethyl affects Gibberellic Acid production, specifically GA1 and this is one of the hormones responsible for stimulating growth/cell elongation. Interestingly Wikipedia states that: “isolated GA was first identified in Japan in 1935, as a metabolic bi-product of the plant pathogen Gibberella fujikuroi (thus the name), which afflicts rice plants; fujikuroi-infected plants develop bakanae (“foolish seedling”), which causes them to grow so much taller than normal that they die from no longer being sturdy enough to support their own weight”. Sound familiar? Yes it does because the phenomenon of ‘Bakanae’ in Rice plants looks almost identical to ETS in Poa. Compare the two pictures below, Rice on the left, Poa on the right, note the extended growth between the leaf nodes in both plant species….

Bakanae

So logically we’d assume that the phenomenon in turf we are dealing with has a similar causal agent and indeed that is one of the theories postulated behind ETS i.e. a Fusarium fungus that stimulates the production of a gibberellin in affected plants and causes the extended, etiolated growth habit. Maybe we’re seeing more ETS because the causal fungi is becoming more widely-distributed due to changes in our weather patterns that suit it’s growth and development ?

Maybe it’s as simple as that, but does TE have a part to play as well, because I’ve noted that areas treated with TE show more ETS than areas that haven’t been and I’ve also had this  feedback from the field anecdotally.

Etiolated

You can test this theory if you are one of the courses / sports complexes that are seeing ETS. The next time you spray a mix with TE, put down a small cover / plastic sheet on an area that normally shows ETS and spray over it, lift it off once dry and you’ll have an untreated area in amongst your treated. Mark the area (photograph it) or use some spray paint if it’s in a non-critical area and see if it produces more or less ETS over time.

You can do the same test with a triazole fungicide because as the fact sheet states it’s been postulated that an application of a triazole fungicide (like propiconazole, tebuconazole, prochloraz) has an affect on ETS by controlling the causal fungus. So if you’re spraying a triazole for a labelled disease, put down a small test area as above and see if you see more or less ETS after spraying? I did this last week so I’ll let you know how it fares.

So how could TE be having an effect on ETS? Well maybe there’s a relationship between how grass grows in the presence of the gibberellin (produced by the Fusarium fungus held to be responsible) and GA1 gibberellin that TE inhibits ? Maybe we see more expression of ETS because GA1 is inhibited? Now I could be entirely wrong on this and maybe what I’ve seen is purely coincidental and just down to the distribution of ETS across the areas I’m treating, but it’s worth taking note of and of course reporting back to this blog what you see, where you see it and what your experiences are. As usual I’d be grateful for your experiences either way…

I reiterate that this is a SWAG of a theory at present (Scientific Wild-Arsed Guess) and at the end of the day it’s not going to stop us using TE because the benefits far out-weigh the negatives, but if there is a correlation, maybe it will help us manage ETS over the longer-term.

All the best…

Mark Hunt