October has been relatively mild to date with plenty of disease pressure and as always there has been plenty of questions about which fungicides to use.
Fungicide Choices for October
My Fungicide of choice for most people has been FR321 and Instrata Elite through this October. As we move forward into November, some of the more northern parts of the country may well start looking towards Medallion but for now I’d stick to these two products in rotation.
2021 had trials at the STRI and we’ve shared the outcome of the trials as they’ve come available.
How rainfast is FR321?
As FR321 is a fairly new solution to the industry and we’ve had lots of rain the rainfastness question was bound to crop up. FR321 consists of 3 products, Heritage, Medallion and Ryder
- Medallion is rainfast in 1 hour
- But will do a good job of spore population control in the the lower areas of the leaf tissue/thatch
- Heritage is rainfast in 2 hours
- Heritage is also taken up by the roots so would still be utilised, as long as the plant is actively growing
We don’t have any rainfastness data on the FR321 one-box solution yet so I’d stick to 1-2 hours as a minimum but the way these products work would suggest that if you were to have any washed off the leaf then much of it would still be utilised.
I would however stick to the concept of when spraying fungicides “the longer it has to dry on the leaf the better“.
But I completely understand for some, a prolonged period of dry leaf is not a luxury they have!
Starting with a dry leaf can also be a challenge. Immediately following rain or heavy due the amount of water being held in the leaf is surprisingly high, so bare this in mind when applying products which need to stay where you apply them, water on leaves will lead to run off more readily.
For some tips on finding spray windows click the picture:
How long will my Fungicide last?
There are lots of things that will influence the longevity of a fungicide but in simple terms the higher the pressure the shorter the amount of control you’ll get. During October and particularly mild Octobers 14 days of control is a realistic amount of time for a fungicide to last.
I’m not suggesting you apply every 14 days but understanding how long it will last at this time of year puts you in good position to ensure you use all the ITM tools available to you to help keep your surfaces clean.
Once your 14 days are up you decide whether the pressure is high enough to apply another one, or if using other tools can keep the pressure down enough to delay your next fungicide application.
As the temperature cools, the longevity will increase and the pressure should also reduce. If you convince yourself that you’ll get 30 days control at this time of year it’s highly likely you will to run into trouble.
To find out more about turf fungicide longevity, we have a blog all about it here.
Its been a bad year for some, but I’ve also seen some people stating to get on top of it following modelling and applying preventatively. Were looking to do some trials in the South West this year to further our understanding, and are also looking to put a Smith-kerns model in place for people to use to help track pressure periods and better target application timings.
So watch this space and I will do some work on this one.
Its been a strange year for peak flight (compared to the previous years we’ve been paying attention). With peak flight, and so Acelepryn applications delayed by about 2 weeks.
The majority will already have the product in the ground by now, or waiting for the right spray window.
On the Horizon
Glenn and Henry now have a significant back catalogue of episodes of ‘On the Horizon’, it’s a great listen!
This is Novembers.