I posted this earlier in the wrong thread: So I have copied it here where I meant to place in the first time.
Looking in the database here, the rust rating for Joan Senior does show it is prone to get rust.
Rust Resistance: Shows Susceptibility
Rust Resistance Decimal Score: 2.5
I have used Green Magic, but not consistently enough to give it a fair rating. I did not notice a drop off in the blooms.
Rust is so variable year to year in the garden, it is hard to know if a treatment is responsible for the reduction in rust or if it is just a year when rust is really bad, or a year when there is almost no rust.
I have tried some new chemicals this year and really thought they were doing a great job because I was seeing no rust in the garden. Then I visited some other gardens in the area to find that I had been using expensive chemicals and had no rust, but these other gardeners had sprayed nothing and also had NO RUST. Darn, I was so shocked when people with no rust informed me that they had not done anything for rust this year and I saw no rust at all in their gardens.
Edited to add:
What I used this year was Azoxystrobin actually Azoxy 2sc Select at 1/2 tsp per gal. mixed with chlorothalonil based on the study shown here. I read it was recommended to use a sticker with it so I did mix in a spreader sticker from tractor supply 1/2 tsp per gal, and added some Miracle Grow 1tbs. per gal.
https://apsjournals.apsnet.org...
