No sooner had I posted a picture of my massive Leicestershire Puffball last week than I was greeted with a “Mines bigger than yours” scenario from my Motherland (Danemark)
No contest I’ll admit size-wise, but judging by the impish look on the wee lads face I think the temptation to give it a swift boot is the same wherever you are Tusind Tak Russell !!!!
Some pretty earth-shattering news reached me over the weekend that the Met Office has lost the BBC Weather Forecasting contract. Firstly I’d like to categorically deny that I am leaving my present position to take up a post at the BBC (Thanks to one of my erstwhile colleagues for that suggestion – wishful thinking eh Mr Dave Howells of Telford in a Father Ted / Golden Cleric type voice ??), but I have to admit I probably share the same amount of hair and dress sense as the above
On a more serious note it will be interesting to see who the BBC turn to for their forecasting information as I understand they are out to tender. I’m also led to believe that the Met Office possess some of the most powerful forecasting computers available. As an ill-informed outsider I think the BBC may have thrown the baby out with the bath water in pursuit of budget, but then we see that a lot in this modern world don’t we ?
On the flipside it could be that they’re looking to modernise their offering and for me in the days of smart phones and tablets, their output is behind the times. Whether this is the fault of the Beeb or the Met Office, I don’t know.
Yesterday whilst out walking in the mountains of The Cevenne, I relied totally on the accuracy of Meteoblue for their rain radar and forecasting and came across a number of French people who benefited from it as well. (They were worried about the risk of lightning)
With 4G now more widespread enabling quicker downloads of weather data I think companies who have anticipated this technology trend like Meteoblue and yR will possibly win out over the more institutionalised offerings, time will tell.
Ok enough of the speculation and onto this week. This unsettled weather sets the theme because all things fungal have been coming out of the woodwork since last week’s blog with the onset of rain, high humidity and high overnight temperatures.
General Weather Forecast
Last week I talked about a Bay of Biscay low pressure that was set to influence Sunday and Mondays weather and not only does it indeed look to be making an appearance but its effect will last a good chunk of this week which means we’ll see out August wet and cooler. Out here in The Cevenne, France, it is the same, with heavy rain on the horizon !
So Monday starts off with that southern rain already into the south coast, whilst additional rain fronts are across Donegal and Eastern Scotland. It’s that southern rain that poses the most issues potentially because during the morning it becomes heavier along the coast and pushes slowly northwards affecting all areas up to The Pennine’s by close of play Monday. At present the worst of the rain looks south coast and possibly south east / east coast of England-orientated, but this could change during the day. West of this across Wales, you look to have a dry start but that rain will just kiss South Wales before moving up into The Valleys, shouldn’t be too bad though. For Ireland, you look to have a dry day after that rain in Donegal moves away, but for Scotland the east coast looks to keep the rain for the day. With an east wind blowing it’ll be much cooler than the muggy temperatures late last week and over the weekend so high teens will be the order of the day.
Overnight into Tuesday and that rain clears England, but stubbornly sits over north-east Scotland overnight and into the early hours of Tuesday. During Tuesday morning however two separate pulses of heavy run push up from the south west reaching Kerry and Cornwall / Devon mid-morning. Again this rain could be very heavy along the south coast early afternoon and with Mondays saturated soil, I expect flooding here for sure. So this rain pushes north east across Ireland and the U.K during the course of Tuesday again reaching up to The Pennines later in the day. That rain over north east Scotland spends another day in situ, so wet up there as well. The wind will swing round to the south west for Tuesday and freshen so wet and windy will be the order of the day for sure and again cool in those strong, blustery winds.
By mid-week we have a repeat of Tuesday’s heavy rain pulses so again expect heavy rain pushing into Kerry and Cornwall / Devon early doors Wednesday and then moving north eastwards, If anything this rain looks heavier than Tuesday’s and at present a line drawn up the M5 to The Wash is in the firing line, as is the south coast again, sorry for you guys down there. By late morning that Irish rain front is across Northern Ireland to leave sunshine and showers behind across The Republic. It has also moved into north west Scotland by late morning and here it’ll join up with the north east rain front to give a wet end to Wednesday across all of Scotland. Further south that rain quickly pushes through to leave sunshine behind but the south east may hold onto that rain through the afternoon and into the evening as will the west coast of Ireland and north west Scotland. Temperatures will be mid-high teens in the rain, but afterwards when the sun breaks through they’ll rise into the low twenties and that may cause some issues agronomically.
For Thursday, we have a slightly drier outlook with a dry start to the day for many areas away from the west coasts. There will still be plenty of rain showers around principally affecting the west coastline of the U.K and Ireland to a lesser extent a.m. By the afternoon that rain will slowly push inland from the coasts of Ireland and the U.K to bring lighter rain to western areas and again into the south west of England. Brighter by the afternoon though between those showers or longer spells of rain so by the evening most areas should be dry and sunny with the last of Thursday’s rain sitting over The Lakes and The Western Isles. Cooler for Thursday with disappointing temperatures for late August, mid teens, maybe a tad higher if you see the sun and still with a moderate to strong south westerly wind calling the shots.
Closing out the week we have a better picture with a lot of areas starting out and staying dry for the majority of Friday, but of course there is a caveat Yes you guessed it, the western coastlines of Ireland and the U.K look to stay unsettled with frequent rain fronts pushing in during the course of the day. Again later in the morning we see those showers push inland across Ireland, Wales and the western half of the U.K and Scotland in particular. So eastern and south eastern counties may stay dry for the whole of Friday and it’ll be sunnier with temperatures lifting into the high teens here. Elsewhere mid to high teens will be the order of the day and winds will be more westerly in nature.
So after a wet, cool and windy week is the weekend looking anyway better ??
Saturday looks to be a drier day for many with only some rain pushing into the south west of Ireland and England during the afternoon / evening a potential blot on the landscape. Clearer skies at the start of Saturday but cloud will push in quickly to give a dullish sort of day unfortunately, but it will feel warmer than Friday with a muggy nineteen – low twenties in the south east. Overnight that south west rain becomes heavier and moves into Wales and the south east of England, but it soon fizzles out because it looks like the wind will swing eastwards on Sunday and this will turn the tables rainfall-wise. That is to say rain is likely to push in to the east on warmer, humid air from the continent and this may mean it’ll be accompanied by thunderstorms and lightning
Tricky one for the start of next week because we still have a low pressure in place and currently it’s projected to be sitting just off the west coast of Ireland so that means the windy and rain theme may well continue for the western side of the U.K and Ireland of course on Monday with the east drier. The boot quickly moves to the other foot though as that low is projected to move eastwards so the rain and cooler weather may follow it on Tuesday, which means drier for the west and wetter and cooler for the east. The temperatures won’t be anything to shout about initially because the winds will briefly shift northwards on Tuesday introducing a chilly feel to the weather in central and eastern parts. For the west it could be warmer on Tuesday and that rise in temperatures will follow to all areas by the 2nd part of Wednesday as high pressure comes onto the scene. Calm and settled for Thursday for most areas but there’s a risk of a new Atlantic low popping up to bring rain into Ireland later on next week. So potentially the start and finish of the week may be unsettled in the west with a warmer intermission between them. For the east it looks like that high pressure will stay in situ, but whether it will dominate into September as it normally does is a different matter.
A lot to talk about this week with the combination of high temperature, rainfall and humidity really ramping up disease pressure. I’d like to tip a nod to last weeks blog when I suggested this would be the case.
One of the key drivers to disease is high overnight temperatures and humidity and you can see from this late night shot of my weather station last week that we had plenty of this…..
Cause and Effect…
So we have identified a set of parameters that are likely to cause high disease pressure, but it’s not that straight-forward is it, life seldom is…Some people will and have said to me that they have sprayed before the onset of this elevated disease pressure and yet they have still seen disease activity, in particular mycelium of Microdochium and Dollar Spot. So why is this ?
Well we have talked about this before during periods of the year when the weather is really driving disease pressure and no doubt we will talk about it again…
Fungicide = Fungiostat
A modern day fungicide is likely to exert a regulatory effect on the speed of population growth of a pathogen so if the pathogen is growing slowly it restricts the rate of growth to a point where it is no longer damaging to the grass plant. In truth this is more accurately described as a fungiostatic mode of action rather than a fungicidal one, because the latter implies killing the fungus (‘cid’ from latin means to kill I think)
Why is this definition important ? Well because when we have climatic conditions driving disease development, sometimes the rate of fungal growth due to high temperature / humidity combinations effectively out-paces the regulatory effect of the applied fungicide. So in essence when you have applied a fungicide that you know is effective and you still see symptoms of disease activity, sometimes this is because the rate of fungal growth is faster than the suppression effect exerted by the pesticide. When the weather / climatic conditions decline (and in our climate they are usually short-lived) then you start to see more effective suppression of the disease.
Of course it isn’t always the case that the above is the only reason why we still see disease activity after applying a pesticide, sometimes it is because there is a lag in terms of uptake. I saw a really graphical illustration of this during July / August, not with a fungicide, but with a selective herbicide.
In July, I sprayed a patch of weeds on a neighbour’s lawn with what I knew to be a very good selective herbicide. I tank mixed in a feed and an iron as well, the former to facilitate uptake. It was very dry and surprisingly to me I saw no effect at all even when we’d had some rain. I thought about repeating the application but in the meantime we had another bout of rain, this time heavy. The effect on the weed was amazing as obviously now it had the opportunity to grow and it was only then that the selective kicked in and the weed died out, some 6 weeks after initial application.
The take home message here particularly with selective herbicides is that if the weeds and grass aren’t growing, don’t expect to see a quick hit, however you may end up seeing one much later in the season if conditions work in favour of growth and therefore uptake.
When we come to fungicides I’m sure sometimes the same is true because much is written about modes of action, but little is actually known in terms of how these translate to the actual scenario of managed-amenity turf, particularly when you’re cutting at 3mm daily.
So let us look at some disease scenarios occurring at present…
Microdochium nivale (Formerly and often called Fusarium)
Plenty of this about with the combination of high night temperatures, rainfall and humidity and with the forecast of another very unsettled week for some areas you can expect this one to run and run. The problem here is do you spray a systemic + contact combination now to knock it on the head and use up one of your effective autumn sprays in late August a month before the main autumn disease period ? As is often the case there is no right or wrong answer.
One option is to spray a contact only (But not a protectant note) and if the formulation allows, tank mix this with some available nutrient to ensure you have uptake of the active (by stimulating growth) In these cooler temperatures, that nutrient should be more ammonium sulphate, potassium nitrate based and you don’t need a lot of it. (5-7kg of N per hectare)
I’d always suggest tank mixing iron as well with this mix because we know the acidification and drying action of some (but not all) forms of iron suppresses disease activity.
The other is the ‘belt and braces’ approach of spraying a systemic and contact combination but for me if you have an acceptable growth rate and are therefore actively growing out the disease then perhaps you should keep your powder dry till you really need this approach (End of September)
Of course you must be the judge of this and your situation will dictate which size hat fits, if you have regulated your turf for example and it isn’t growing much then the chances are the disease will definitely have the upper hand.
Red Thread & Dollar Spot
Now here’s an example of two diseases, the activity of which is definitely affected by PGR usage. Last week I looked at some tee areas which because of poor irrigation design (I see that a lot) were very dry and had poor grass cover. The superintendent had also applied a PGR at 1 litre per hectare as was his usual practice, however with the benefit of hindsight this was a mistake because the turf areas were truly rammed with Red Thread, much more than I’d ever seen. For sure regulating your turf with a PGR will definitely increase the activity of foliar pathogens like Red Thread and Dollar Spot, if climatic conditions are conducive for their development. Much better for me to let the grass plant naturally grow it out and you decrease the level of mycelium by clipping removal.
I can hear the shouts of “Rubbish” and “Humbug” from those of you who have shares in TE, but unless you are maintaining a turf with higher pesticide inputs or where disease levels are naturally low I think using healthy plant growth to grow out disease is an effective strategy for these two diseases. So if in doubt, grow it out……
Before I leave Dollar Spot, I had a nice piece of anecdotal evidence to this effect from a good friend of mine (Ta Adam) showing some really aggressive Dollar Spot on a bowling green.
He remarked that if the grass growth on green was healthy then it typically showed little disease even without spraying, but if it was put under stress (drought = lack of moisture = lack of nitrogen) then the green would show aggressive Dollar Spot activity.
Will it or won’t it / Is it or isn’t it active ????
Sometimes when you look at disease activity it is difficult to tell whether it is active or not so here is a tip…
Take a sample from the affected area ideally on the edge of the disease patch (because the fungus is growing outwards) and put it in a sealed plastic bag or sample jar overnight. To help promote disease development, give it a nice misting spray before you do so.
Note – I got a great ‘Mister’ free of charge recently with a bottle of Girvan’s finest Hendrick’s Gin, if ever there was an incentive to drink G & T’s, this was it for me !!!!!!!
The above picture shows a sample of Dollar Spot which had this treatment and you can clearly see the formation of mycelium on the plant tissue so it is active and if conditions conspire it will continue to cause plant damage.
I am seeing some activity out there, in the above case the image is of Foliar Blight Anthracnose on one area of fine turf. What was different about this area ? Well it was a raised, dry area of a green that had dried out during the hot, dry, high E.T days of July and because the plant was under stress it had fallen victim to this pathogen.
With the heavy rain forecast for this week in some places I expect to see an increase in Anthracnose activity, but more Basal Rot than Foliar blight. I hope you heeded the warnings in July, however if you have signs of activity, I’d suggest applying a granular rather than foliar fertiliser because undoubtedly this will be more effective during the coming weeks wet and unsettled weather, plus you’ll be able to apply it more easily than a liquid !!!
High Temperature and Humidity = Rhizoctonia
It isn’t often I see an image that makes me stop in my tracks and think hmmmm, but such was the case last week when I got this pic from hyper-fit Alex (Cheers matey)
This image was from a football pitch but the last time I saw something like it was back in 1997 in the south west of England. ( In that case it was on a green ) This looks to be Rhizoctonia Solani and is a disease that is really driven by humidity and temperature together. Interestingly in the notes on the disease from the U.S, they also think it’s activity is encouraged by the over-use of organic fertilisers.
Algae / Squidge
I’ve had a number of texts / emails showing Black Algae colonising areas of turf and queries relating to treatment. Obviously it’s there because the areas are wet consistently at present and also because they may have thinned during summer stress (but not always). In the old days Daconil showed some activity on this phenomenon but personally I think you’re best approach if possible is to lightly aerate and topdress to naturally dry the area out. That said with this week’s forecast it may well predominate I’m afraid.
If any of you have had success treating with iron or anything else for that matter, please email me or drop a comment in.
Ok that’s all for this week, bit of a mammoth blog, my apologies
All the best.