Unfortunately fairy rings are quite challenging to conduct trials on, it’s part of the reason you see them appear on so few fungicide labels.
As you’ll know some years are better and some worst for fairy ring appearance, this makes getting meaningful data over multiple years on their control a big challenge.
For example if you don’t have a flare up of fairy ring symptoms in your untreated control plots the trial would not be valid/meaningful.
Meaning for a disease like microdochium, which you can pretty reliably get in trial plots year on year, it’s fairly quick and easy (ish) to get a data set to add that disease to the label, but every time a trial fails due to low pressure and needs repeating the costs go up, so many manufacturers don’t persist.
You can read more about fairy ring generally in this blog from last year.
Some good tips for tackling fairy ring in this article also.
I’ve got three golf courses helping me with the fairy ring user trials this season.
We’re going to look at the affect of temperature at time of application as the ‘variable’.
This comes from a lot of work done in the US which has shown this to be an important factor for how successful you’ll be.
So, same products, program, water rate and spray techniques, just two different start temperatures.
It’s all investigating the notion that fairy ring fungi, much like grass have times of active growth and times of dormancy.
We can’t see the fungi so it’s strange to think of them in this way, but when it’s too cold they are not growing, and organisms which are not growing are more tolerant to stimuli.
If you don’t believe me think:
a) Broad leaf herbicides like Overtake; spray on a weed when it’s not actively growing and it won’t take up the product or transport it around the plant, and so it does not have the desired effect and control the weed.
b) Very late Acelepryn applications for leatherjacket control; if the grubs are down deep, dormant, because it’s cold we don’t get such a good effect because they are not taking on the active ingredient.
So we also have this “Goldilocks zone” with fairy ring applications.
Below a certain temperature the mycelium which make up the main mass of the fairy ring will not be growing. If we treat at that time the product will:
- Struggle to come into contact with the pathogen
- Be less effective, as the fungi is not undergoing normal metabolic processes – which are what the a.i’s in the products interfere with
On the other hand, leave it too long into the season and the fungi has already grown huge, attaching it now will be a bigger challenge for the product and also if you do win, the symptoms will still show.
Dead mycelium/fungal matter breaking down is what produces that characteristic greening up of the turf. So you succeeded in controlling the fungi but you still got the green ring of stimulated growth you didn’t want.
So the 3 courses in the trial have two different temperature thresholds to spray at; 12°C & 15°C.
We’re talking two week average soil temperatures, as tracked in TurfAdvisor here.
When they hit 12°C for their site they go spray half of the greens in the trial, then spray the same greens again 14 days later.
When they hit 15°C they spray the second half of them, again following up 14 days later.
All the sites have already treated for the first 12°C application, so I’ll keep you posted how the trials progress and if we can pick out any difference between the two application timings at the end of the trail…
