So only a couple of days before the longest day and then we start our inexorable slide towards the autumn 🙁
It always kind of confuses me when we reach this point in the summer, well before summer has actually taken place and the same for the shortest day around the 20th of December. Usually the worst part of the winter occurs well after this date. One cannot argue with the consequences of earth’s rotation though, so I won’t.
Over the weekend some of you enjoyed some rain showers but for many we got very little at all and with drying winds its effects were soon gone. That puts us in a prolonged dry period, particularly for the east of the country with <20mm of rain in May and practically nothing to shout about in June either. Here in the Midlands we have had 1.8mm over the last 3 weeks and looking at the outlook we have an Atlantic blocking high pressure developing this week which will push any rain over the top of the U.K. This will make June one of the driest months we have endured for a good few years I reckon. Will we get payback in August I wonder ?
Before I go onto the weather, a quick aside. As many of you will know I love nature and together with the 4 Hedgehogs I now have visiting the garden nightly, I put a number of bird feeders up and some fat sprinklers for the Thrushes, Blackbirds, Robins, Dunnock and the like. Now for a long time it’s been a source of constant frustration to me to see a big fat Squirrel empty the feeders on a daily basis. Catapults and water pistols are fine but when you’re out at work, they can do their worst and you come home to an empty feeder 🙁
So I researched Squirrel-proof feeders and found this one accompanied by good reviews ;
It’s called the Brome Squirrel Buster Mini and I think it works 🙂
If anything heavier than 700 gms hangs on the feeder, the spring compresses and the inner feeder slots into the outer guard, effectively denying the weighty Squirrel access to the contents of the feeder. You can alter the trigger weight if you have thinner-than-average Squirrels visiting 🙂
The instructions say you should hang it 18″ away from as feeder, tree, post, etc to stop the Squirrel hanging over and attacking it from the side.
Mine is about 12″, 30cm away and I am pleased to say that after 2 weeks it remains unmolested by those bloody Squirrels and I now have a thriving number of young birds (Coal Tits, Robins, etc) visiting on a regular basis no longer intimidated by a tree-living Rat.
Ok back onto the weather for the coming week….
General Weather Situation
It’s a north-south and west-east divide for the beginning of this week with frontal systems affecting the north and west whilst the south sits in a period of calm, fine and dry weather. Today we start dry in all places but by mid-morning a rain front will push into the west of Ireland preceded by a bank of thick cloud. This rain will cross Ireland on the back of a westerly wind and push into the west coast of the U.K by late afternoon. Anywhere from Wales up to south-west Scotland will see thicker cloud and rain showers developing through the afternoon with rain pushing into northern England and across Wales this evening. All the time staying west though. The afternoon rain that pushes into Scotland will soon fizzle out through the evening as will most of the rain across Ireland, becoming isolated to the south of the country. East and south of this will see a fine, dry and settled day with varying amounts of cloud. In the sunshine temperatures will pick up markedly into the low twenties for the south of England, high teens, low twenties for The Midlands and mid to high teens further north with Scotland and Ireland slightly cooler under that cloud cover. Winds will be moderate and westerly.
Onto Tuesday and we see a re-run of thick cloud and rain building across the west of Ireland before rain sets in from early doors. This time the trajectory is more north-west and the rain is heavier and so we will see showers develop along the north-west coast through the morning and afternoon. Later in the afternoon that rain over Ireland becomes much heavier across the north-western counties and this rain then pushes across The Irish Sea into Scotland and the north west of England during the evening to give a particularly wet night for the north west. South of this rain event we see England and Wales dry and settled with cloud cover burning off during the morning to give a hot, dry and sunny day with temperatures pushing up into the mid-twenties again across the south of England. Again cooler across Ireland and particularly Scotland under that thick cloud and evening rain with temperatures struggling into the mid-teens.
Onto mid-week in a jiffy and the longest day. Overnight and Central Scotland will see that heavy rain pushing through and out into The North Sea so a dry(ish) start for most on Wednesday with lighter winds. I say dry(ish) because North Wales and the north of England may still see some rain courtesy of that overnight frontal system as we start the morning rush hour but this will soon fizzle out. It will however leave thicker cloud around for many on Wednesday so a slightly cooler day for the U.K and Ireland, except for the south-east of England which will see clearer skies and hotter temperatures, again climbing into the low to mid-twenties. As I mentioned earlier we have a blocking high developing out in The Atlantic and on Wednesday we will start to see the effects of this high pressure introducing northerly winds into Ireland and dropping the temperature down into the mid-teens. Further east we will see light westerly winds but these will change overnight to a northerly.
Thursday sees those light to moderate northerly winds in place so a cooler day for sure. That change in the wind direction may just push some rain down the north-east coast of England across into East Anglia overnight but we will see. Other than this we look dry for the whole of Thursday with varying levels of cloud and sunshine. The northerly wind will drop the temperature considerably across the south of England down into the high teens with Scotland and Ireland a couple of degrees lower.
Friday starts off clear and cool after a chilly night where temperatures will drop into single figures. Through Friday we see cloud build, particularly over the north and west and this cloud bank will move south through the day to give a dry but hazy sunshine kind of a day for most of us. Again with a cool northerly wind in situ we will see temperatures locked in the high teens perhaps just breaking twenty degrees across the south of England. Dry again though.
Dry and settled is the forecast for the weekend with varying amounts of cloud and a north to north-westerly wind in situ. This means we will remain on the pleasantly cool side with cloud cover and that wind keeping temperatures down into the high teens. High pressure looks to remain in charge for the foreseeable so dry and settled it is.
High pressure looks to start off next week so remaining dry and settled but not especially hot because of the position of the high and the orientation of the wind. Through the course of Tuesday next week the high looks to get pushed south very slowly by a northerly low so we start to see some unsettled weather move into the north of the U.K and perhaps push further south as we go through the week. So I think a dry start to next week but more cloud and some rain making an appearance in northerly areas first and then perhaps later in the week further south.
So last week I mentioned that the third week of May provided the conditions conducive to Anthracnose spore germination for definite and that early May when we also had high temperatures was unlikely to have provided the necessary conditions because the humidity wasn’t high enough during this period.
This assertion regarding the early May temperatures has been proved wrong because late last week saw my first diagnosis of active Anthracnose, mainly foliar blight on Poa annua. If you work it back that’s 5 weeks since the early May high temperatures so the finger points strongly to this period being responsible for triggering fungal growth.
I decided to re-look at my weather data from this period using my own weather station as a source of data.
So here’s the data from May 1st till present day looking at air temperature, rainfall and humidity and remembering that we need a minimum of 25°C for 2-3 days to start spore germination.
So you’ll see two highlighted boxes on the graph above (red dashed lines), the first at the beginning of May when we hit 4 days > 25°C from the 5th and although the humidity wasn’t high during those 4 days it was immediately afterwards because we got rainfall.
If this early May event was indeed a trigger, it appears we don’t require temperature and humidity at the same time to generate fungal growth, rather we need the humidity straight after. You can see for the period of the 19th May onwards, we had both high temperature, high humidity and rainfall so that definitely provided the correct combination of conditions for disease development.
Now this doesn’t mean we will see rampant Anthracnose this year, more it’s one piece of the puzzle. The defining piece is whether the grass plant we manage goes under stress as Anthracnose is a stress-related disease. I believe when a grass plant is under stress it releases hormones (similar to humans) and the presence of these hormones acts as a trigger to disease growth within the grass plant, effectively switching the disease from a biotroph to a necrotroph.
It’s just a theory of mine. Of course the main stress we see during the summer is drought stress and with some areas of the country especially dry it isn’t beyond the realms of feasibility that we will see this disease manifest itself in foliar blight form from now on. Of course the other trick it has up its sleeve is that Anthracnose can also develop as a basal rot during periods of prolonged leaf / crown wetness so it can be of equal issue during a wet summer.
The idea therefore is to minimise stress, maintain plant health in terms of adequate and not deficient / excessive N nutrition and keep doing those all-important good cultural practices.
Now sometimes in this job you get sent an image which introduces more than a couple of frowns to the forehead. Such was the case last week when I got this in my inbox…
So kind of vague yellowing, some areas showing stimulated green up around the circumference.
We duly sent a sample off to Kate @ The Turf Disease Centre and I nipped along to have a look at the actual symptoms. What struck me was that the appearance was related to grass species distribution across a green rather than a specific ring or patch. The grass looked like Poa annua to me and if I guessed I’d say it was more of a annual biotype because it was coarser-leaved and seeding still. My first thought was either a plant-parasitic nematode species or perhaps Waitea (because of the pronounced yellowing) / Superficial Fairy Ring. On examination there was no depression in the area, no smell and it was only present on a few greens which had this grass species / biotype present.
Whilst I was at the club, Kate’s disease diagnosis came in and promptly re-introduced that frown to my forehead.
As you can see from the image above the disease was diagnosed as Take All or to give it its proper lardy-da name – Gaeumannomyces graminis var avenae.
So here we have a disease present on Poa annua rather than its more normal host, bentgrass.
Rather than showing as rings of dying turf it seemed to be only affecting specific Poa biotypes. My SWAG (Scientific Wild-Arsed Guess – Copyright Dr James Beard) is that this type of Poa was shallow rooted and therefore particularly susceptible to stress / desiccation. So the combined effect of this pathogen and elevated stress levels (the course had struggled with an irrigation system problem) was enough to tip the plant over the edge and display yellowing (probably as a result of poor nutrient uptake through a compromised root system)
It just goes to show you learn something new every week in this job and goes a long way to explain my well-furrowed brow 🙂
PGR applications on greens and longevity….
Did a little look at the temperatures we have had lately in The Midlands and correlated them to GDD.
Working on the U.S principle of applying every 200GDD (calculated using 0°C as a base) or approximately 130GDD ( (calculated using 6°C as a base), I reckon a PGR application on greens is lasting 12 days at present before we see rebound and that’s regardless of rate. Looking ahead we have some cooler nights from mid-week when that north wind kicks in so this will probably stretch out to 14 days through the next period. The bottom line then is to keep applications tight.
Ok that’s it for this week…
All the best…