August 19th

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Hi All,

Firstly, an apology, I got Friday’s forecast very wrong, so instead of a dry day, alot of areas received rain, we got 24mm here for instance. That raHeatAug192013in may be a welcome mistake mind as it looks like we’re heading into high pressure this week. That means the return of heat for some, particularly towards the end of the week, when I expect temperatures to hit the high twenties. You can clearly see the heat pushing up in this graphic for Thursday this week, from Meteoblue. Of course the question is, will it last for the U.K Bank Holiday ?, maybe for the beginning of it, but I think we’ll be getting some rain as well, potentially heavy to boot.

For the last 3 weeks we’ve been going through an alternating cycle of mini peaks and troughs, so we build heat during the week (under a peak like this), then we get a low pushing through, then we build heat again after it. For the near future I can see this pattern continuing into September.

Rainfall Data

Thanks to all you guys for the rainfall data, Paul in I.T is busy collating it as it comes in, but I charted out the top 10 driest and wettest so far and it makes interesting reading ;

RainfallaUGU2013

It suggests that the rainfall pattern has been very much north and west, moving in a diagonal orientation (/) over both Ireland and the U.K, so the north and west of the country gets the heavier rain and the south and east, less.  It’s also interesting to look at the last 2 months pattern as well ;

RainfallJulyAug2013

Now the data is from 60 or so venues so far, but it’s clear to see that some areas of the U.K and Ireland were extremely dry for June and July. I’d also note that the high reading for clubs in The Midlands came from one deluge at the end of July. We’ll present all the data in a link from next week’s blog.

General Weather Situation

As initimated above, we are in for a pretty nice week’s weather, over the vast majority of the U.K and also Ireland, with heat building in the central and southern regions of the U.K during the week and that may trigger off some thunderstorms for the Bank Holiday there.

Monday see’s a cool, bright start for many in the U.K and Ireland with light westerly winds (Geez didn’t it blow on Saturday !) and hazy sunshine gradually pushing the temperature up to the low twenties in the south of the U.K. Further north it’ll be cooler with more cloud cover and the chance of light rain for the north-west of Scotland. Tuesday see’s pretty much a re-run of Monday with perhaps more sunshine in the afternoon pushing temperatures a little higher again and those winds maintain their light, westerly / south-westerly orientation.

Overnight a rain front clips the north-west of Ireland, so rain for Connacht early doors to start Wednesday and also Scotland, where the same rain front will bring light precipitation to the north-west initially and then it’ll sink slowly south, dissipating as it does so over the borders. Further south, that heat keeps building from the continent, so expect mid to high twenties. For Thursday, we have pretty much a dry picture for all of the U.K and Ireland (not often I say that), with variable cloud cover burning off in the afternoon to push temperatures up into the high twenties, maybe clipping thirty degree’s in some areas. During the day, the wind will push round to the south-east, but it’ll be light and barely noticeable.

Friday sees a change as a low pressure system begins to push in from The Atlantic and as it does so the wind will push round to southerly, then finally westerly heralding the arrival of moisture to the south western coast of Ireland by the afternoon and this will push across country into the west coast of the U.K by early evening, but amounts will be light. It’ll still be pretty warm though, with temperatures again high twenties in the central and southern region.

The Bank Holiday weekend (U.K only) is going to be a pretty tricky one to predict with this movement in from the west of moisture butting up against the very warm continental air mass. At some point we’re going to get rain for sure and that rain may be potentially heavy in nature, particularly across the south of England. I think Saturday is likely to be potentially the wettest day, but because this is moisture pushing up against continental air, it’s almost a waste of time trying to predict whose going to get it a week away, so I’m going to do an update at the end of the week when the patterns look clearer. I do think the temperature will slip back to low twenties though under the influence of that low and that means high teens for Ireland and Scotland, with more in the way of sunshine and showers here for the start of the weekend.

Weather Outlook

As mentioned above, the Bank Holiday is a tricky one to predict rainfall-wise, so I’ll update on Thursday. Looking further than that, I think once the influence of that low pressure pushes through, we can expect a quiet start to next week, light winds and temperatures in the low twenties. Thereafter I think that’s the way it’ll stay until the end of the week, when another low is due to swing in, maintaining our alternating high-low-high pattern of late.

Agronomic Notes

Heat Stress ?

The heat that’s arriving this week will be different in nature to the July heat so I don’t expect it to put the plant under so much stress. Why ? because the winds will be lighter, so E.T rates will be lower and also the night temperatures will be mid-teens, so the temperature will not be consistently hot through the day, it’ll take a while to crank up.

GDD data predicts Growth Flush

Using GDD data, I thought it would be a good idea to look at the potential for growth coming up to the Bank Holiday weekend and as you can see from the graphic below it suggests that we’re going to get a flush of growth going into it unfortunately. This works on the assumption of course that there is enough moisture in the ground to generate this growth, but for the west and central areas, this is definitely true.

gddpredAug13

Chart showing predicted GDD data for Market Harborough during the coming week

A GDD figure above 10 suggests good growth to me and above 12, very strong growth, so you can see the potential issue coming up over the next week or so. On the strength of this, I’d definitely be looking at applying a PGR (if time and budget is available) on any outfield areas you’re looking to keep in check over the Bank Holiday and beyond, because if this data is right, it’ll take a good deal of sorting out next week when we’re all back at work !

Disease Pressure

Not really a disease, but with the almost autumnal weather of late, we’re seeing a lot of Etiolated Growth around, especially on collars and aprons with their higher height of cut. It’s a pain visually because it doesn’t tend to cut easily pushing down in front of the mowers, so the use of a brush may come in handy here. As I’ve mentioned in the past, this phenomenon is thought to be due to the presence of a Fusarium fungal species (not the normal one we deal with) that produces hgih levels of gibberrellic acid. I produced a fact sheet a while ago which you can download here – Etiolated Growth Fact Sheet

Etiolated Growth

The jury’s still out on whether you actually get some measure of control as a side effect of applying a Triazole fungicide, some people say you do, some don’t.

Disease Pressure -part 2

StuntPPN0813

Ectoparasitic nematode damage on Poa annua in an otherwise very nice, high bentgrass content sward

I’m seeing and I know Kate’s getting, alot of plant parasitic nematode (PPN) samples in lately which are mainly Ectoparasitic in nature, with Stunt nematodes occurring in high counts. These are ones that sit outside the plant (most of the time) and feed on the root causing quite serious cases of decline. Nematodes are Poikilothermic (lovely word for impressing people :)), it means cold-blooded, and so the very warm weather of July will have seen rapid increases in population, which their subsequent detrimental effect on the turf. Sometimes these show up as ‘hot spots’ of activity, sometimes they just look like an area of turf that is more drought-susceptible than surrounding turf, because the root system has been damaged by the activity of the PPN and the plant is struggling to regulate moisture uptake / loss, particulartly on high E.T days.

The appearance of the damage caused by Ectoparasitic nemadotes may not be down to the activity of the nematode alone, often there are secondary organisms, typically fungi that then attack the weakened plant, so you have a complex situation to manage. It’s also true to say that Poa tends to be selectively targeted in a lot (but not all) of PPN cases, such as in this image.

Other than that we have the usual suspects of Fusarium in areas that received rainfall at the end of last week, this should die down a bit as the leaf dries out, but on the flip-side, I do think we may get some heavy dews this week. Fairy Rings / Thatch Fungus has also been very active of late and I expect this to continue in the high temperatures / humidity expected this week, so a bit of a pain really.

Have a good week and I’ll do a mini-update on Thursday to let you know how the Bank Holiday is shaping up rainfall-wise.

Mark Hunt

 

 

 

2 thoughts on “August 19th

  1. Matthew James

    It has been quite noticeable for us for the second year running now that a top dressing operation has been the catalyst for a nematode outbreak. In my view, the stress caused by brushing or drag matting is enough to tip the balance in favour of the nematodes. We had a couple greens tested last year by Colin Flemming and our root-knot numbers were very high. Even if we go for another test now, there is little evidence to suggest spending vast amounts of money on some remedial products is worthwhile. Although aour symptoms are relatively mild, we are carrying out measures to “de-stress” the plant by keeping up aeration, maintaining adequate moisture and holding off further top dressing for the moment.

    Reply
    1. mark.hunt Post author

      Hi Matthew,

      I wouldn’t disagree with your observations as plant parasitic nematode (PPN) damage is closely linked to plant stress levels in my experience.
      The problem is it is also very closely linked to plant health and particularly rooting effeciency as well.
      I’m tripping over issues with PPN’s on a regular basis, often they’re affecting a set of greens within 18 holes and the greens that are worst affected nearly always tend to have high levels of surface fibre and / or compacted fibre. Either way the rooting is bridged, lateral and therefore ineffecient at both nutrient and water uptake meaning the effect of the nematode is exaggerated, particularly when you put the plant under stress.
      Furthermore by dropping topdressing you’re very likely to build compact fibre if you’re not careful, I’m guessing you mean holding off whilst other environmental pressures (high E.T periods) are present and commencing again when thinsg settle down ?
      Otherwise for me you’re ticking all of the boxes, maximising plant health, plenty of biostimulants, frequent aeration (to encourage new roots unaffected by the PPN’s) and minimising plant stress culturally. I’d also be lowering the rate or dropping out completely PGR usage on greens when PPN issues are prevalent as I do not believe it helps the plant grow away from the effect of the PPN.

      Reply

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