Spray or cut down Hawthorn tree with Juniper/Hawthorn Rust?
My semi-mature Hawthorn tree (transplanted Oct 2015) is severely infected with Juniper/Hawthorn rust. I don't have Junipers in my yard (maybe a neighbour has the Juniper) but I do have many large mature cedars. However, my cedars are not showing any signs of infection.
Should I spray my Hawthorn with a Fungicide - or should I remove it? I don't want to endanger my cedars.
Outside United States
The "cedar-apple" rusts have many different life cycles depending on the species of rust. The key will be to figure out which you have or which are prevalent in your area. Each of these fungi alternate from a conifer host to a roseseous host. If the rust on the hawthorn has a chance to infect the cedars then it is the cedars that need spraying when spores develop on the hawthorn. Since the cedars show no signs then you may not need to worry at all. But if you want to be sure and protect the cedars then removing the hawthorn may be in order. (But only if you have the correct species of rust in your area.)