I was reading New Scientist this weekend in a rare moment of calm and they had an article on the latest U.S Super-Storms that have hit the Southern United States and the ongoing debate as to whether they are caused by Global Warming. Now Hurricanes are a natural feature of the weather and seasons in that part of the world so their occurrence certainly isn’t but their new-found strength is linked to abnormally warm water in the Gulf of Mexico and a unusually slow storm path wherein the weather system gets stuck in place dumping high levels of rainfall over short periods. Sound familar ? Both of these features are implicated as a consequence of our warming world…..Good job Trump demonstrated good future vision by rolling back all of Obama’s Flood Defence Protection initiatives just days before Hurricane Harvey struck. You can almost imagine Mother Nature giving Trump (dressed as King Canute) the finger….
I’ve also been busy working on my garden and I was amused to see this label stuck to the top of a wooden stake I was using…….Judging by the ingredients of the wood treatment, I think there might be a nice little earner in hanging around wood yards and buying some treated wood chip 🙂
Ok onto the weather and is that Indian Summer making an appearance or are these strong Atlantic low pressure systems putting paid to that idea ?
General Weather Situation
So for Monday we have a somewhat messy weather picture with low pressure from last week sitting over Europe, another one north west of Scotland and high pressure squeezed in-between. Now this scenario will settle the weather for a few days but that high pressure won’t dominate I’m afraid so expect change as we approach the end of the week, but it’s not all bad news…..As inferred last week, the north and east are likely to pick up some wet weather this week due to the proximity of the low pressure system over Europe. So today we have a relatively calm and dull start to the week. That thick cloud layer over the U.K and Ireland will break up to give a nice sunny day with pleasant temperatures. Across the Irish Sea we may see some rain creep into North Wales, The North West and East Anglia by late morning and this will be joined by some thickening cloud later in the afternoon over Scotland, the north of England and Wales. By the evening this rain sinks southwards into The Midlands before fizzling out. So a mixed start to the week and temperatures where you’d expect to see them of late, mid-teens, held back by that light to moderate northerly wind.
Onto Tuesday and again a dull start for us all but that cloud cover will soon break to give long spells of sunshine over most of the U.K, with the possible exception of some rain brushing the coastline of East Anglia again. Through the morning Ireland will see thicker cloud across the west, but pleasant sunny intervals along the east coast. By the afternoon, this thicker cloud over Western Ireland converts into rainfall which pushes cloud and rain across all of Ireland for the 2nd part of the day. The U.K looks to stay largely dry all day Tuesday and with light winds shifting round to the west, we will pick up a degree or two temperature to hit the heady heights of the high teens in some places 😛
Mid-week beckons and that rain over ireland pushes across The Irish Sea overnight to grace the north of England and Scotland with its presence. Menawhile a new rain front of potentially heavier rain is set to make landfall around dawn on Wednesday in Kerry and bring heavy rain to the west coast and Midlands of Ireland. The U.K looks to have a dry morning until that western rain pushes into Scotland and West Wales by early afternoon with Wales, the north of England and Scotland in line for the worst of it I’m afraid. Further south we look to stay dry for most of the day as that rain stays more northerly. Much stronger winds on Wednesday and from the south west so mild everywhere with mid to high teens again the order of the day.
Onto Thursday and that rain overnight has formed a vertical band straddling The South West, Wales and the west coast of the U.K, expect it to be potentially heavy. This band of rain looks to straddle the M5 for most of the day so if you’re driving up or down that motorway, take care on Thursday. West of that band of rain we look to have clearing skies and a predominantly dry day for Ireland and Scotland, though the far north east of Scotland may pick up some heavy mizzly drizzle. Sunny intervals for Ireland but thicker cloud will give a dull, cool day for Scotland though this is expected to clear from the west in the afternoon. By dusk that rain band has drifted east and south and is expected to lie from Bristol diagonally up to The Humber crossing The Midlands, so south of this line should stay reasonably dry but predominantly cloudy. Strong to moderate south westerly winds again for Thursday and mid-teen temperatures maybe pushing up into the high teens in the south of England.
Closing out the week on Friday and we have a dry sunny start across Ireland and the U.K but it won’t last for the latter because by early afternoon a rain front will push into the west of Ireland and rapidly move eastwards crossing Ireland during the mid-late afternoon. For the U.K we have a really nice autumn day with light winds and plenty of autumn sunshine so a cracking end to the week here with long spells of sunshine expected with maybe more in the way of cloud across Scotland. Temperature-wise I’d expect low to mid-teens across Ireland under that thicker cloud and rain and mid to high teens for the U.K depending on cloud cover.
So how does the weekend look ?
Well we have high and low pressure battling it out but this time the high pressure is out on The Continent so it’ll shift the wind direction eastwards and that should keep the deep Atlantic low pressure system lying north west of us out of the picture. So a nice dry weekend beckons with light easterly / south easterly winds and plenty of sunshine. (There you go Mr Collins 🙂 )
So a settled weather picture to start next week ? No not really as we have a sneaky low forming in The Bay of Biscay and that might bring rain across the south west and south coast of the U.K for the early part of the week. Tricky to say at this stage because it really depends on the behaviour and position of this low pressure. If it’s close to the south coast of the U.K then we can expect unsettled weather for the south of England but drier for the north, west and Scotland. At this stage I think we will see some unsettled weather at the start of next week but it’s likely to be more south and east of the U.K that is affected. With strong south easterly winds in place we should retain some decent temperatures. By mid-week we have a deep Atlantic low coming in and it is a cool one as well (the first time I’ve seen blue on Unisys for awhile) and that looks to bring unsettled conditions with potentially heavy rain into Ireland for Wednesday before crossing the Irish Sea into Wales and the rest of the U.K from Thursday onwards. A wet end to the week then possibly with strong south westerly / southerly winds I think.
There’s been a lot of Dollar Spot about this season, both here and on the continent and undoubtedly the driver is the wet summer, high humidity and extended periods of plant leaf wetness. It tends to affect tees, fairways and approaches here more than anywhere else rather than greens but I know this is different on the continent with more fine turf areas affected.
There may be a number of contributing factors as to why higher height of cut areas are affected more but I think one of them is related to plant leaf wetness. I think it is likely that on the areas affected, the plant leaf stays wetter for longer because most courses don’t physically remove the dew off fairways (although some do with late season tournaments). It’s also related to improved plant health on greens vs. fairways and possibly because we are already applying fungicides on greens for Microdochium control that will also control this pathogen. Saw a classic case of this last week on approaches and you can see the line of demarcation quite clearly between good nutrition combined with a light rate fungicide vs. untreated…
Growth Patterns – September to date…
We have had some pretty chilly nights over the last week or so courtesy of a strong northerly airstream and you can see from the chart above that we touched close to 5°C on Friday and Sunday during the night. That knocked the Growth Potential right down (as well as triggering my central heating to come on unexpectedly…”In September ?, Not on your nelly !” says me….) from its near optimum of the week before and hopefully allowed you to get on top of grass growth on outfield areas in particular. That’s quite early in my mind for the temperature to drop this low but its worth thinking about the consequences of this looking at the week ahead.
Obviously greens growth will have dropped off with this sharp reduction in temperature and that brings me onto the perennial debate concerning PGR usage late in the season and the pros and cons of this. Obviously one of the key areas going forward is PGR usage with respect to increased fungicide efficacy, it is a logical thought process in my mind that if a plant is regulated going into the autumn (and particularly during October) then it will extend fungicide longevity. Of course every coin has a flipside and if you have active disease and you have regulated your grass plant then it will be slower to grow out, this is also logical and one of the reasons why some foliar pathogens are more aggressive on grass that has been treated by a PGR.
There’s also the question of combining a PGR and a fungicide in the same spray tank. I know a number of people do this with apparently no issues in terms of phytotoxicity (plant yellowing), but what about efficacy ?
How do we know that a joint application of a PGR with a systemic fungicde (specifically) doesn’t affect the rate of uptake and efficacy of the latter ?
To add further to factors that we have to consider, we know that one family of fungicides in particular, the DMI’s (Demthylation inhibitors), which include Propiconazole, Tebuconazole, Difenoconazole exert their own plant growth regulatory effects to varying degrees, with some actives more regulatory than others. So by applying a PGR with a DMI we do have the potential to cause some yellowing of the plants within a sward and specifically annual Poa annua biotypes. I’ve looked for some research on this subject and found quite an interesting example on this link – http://turf.unl.edu/turfinfo/July9%20PGR%20Over-Reg.pdf
For me I think it’s something an end-user can evaluate very easily in the field themselves on their surfaces by trialing an extension of PGR usage up to the end of October on say 9 greens / tees (because disease on tees last autumn was both aggressive and common) or half a sportsfield vs. untreated.
Why up to the end of October and not beyond ?
Well in a normal autumn we tend to have a sharp drop off in growth from the beginning of November (usually after a balmy Halloween with high disease pressure) and often the combined growth during November and December isn’t equivalent to October on its own from a GDD and G.P perspective. So there’s a strong argument that Mother Nature does the job from November onwards though in 2015, there’s a counter-argument that you could have continued PGR usage right up to Christmas such was the extent of the mild weather !
It is without doubt a complicated debate with as many pro’s as con’s but it is an important one as we look to develop and improve disease management strategies in the light of the loss of effective fungicide chemistries and the arrival of lower A.I-content replacements.
The week ahead…
So looking ahead at this week you can see that the cool northerly winds are keeping the G.P / GDD down in the early part of the week but as the winds lessen and change direction we pick up some pretty good growth at the end of the week / weekend. So if you have spray windows I think it’s a good time to get your last hit on weeds prior to the onset of autumn proper. Picking up greens with foliar nutrition will also be beneficial provided you have gaps between the rain (more of an issue for Ireland and Scotland this week I think) . Overseeding of thin / worn areas from the summer will also continue to be effective as we look to keep good air (and therefore) soil temperatures through the latter part of September as per usual.
Ok that’s me for another week.
All the best…