cedar-quince rust

Asked February 28, 2018, 12:23 PM EST

My service berry trees have what I believe to be cedar-quince rust. Is there an anti-fungal spray that I can purchase to treat this? I understand that sprays containing ziram are recommended but I haven't been able to find a spray locally that contains it.

Kent County Delaware cedar quince rust

3 Responses


Cedar quince rust caused by the fungus Gymnosporangium can affect leaves, fruit, and twigs of the quince trees. It overwinters in swollen twigs that may have an orange appearance, especially when spores are produced on those twigs in the spring. You can prune out the worst affected twigs/branches, and rake up and remove fallen infected fruit. If the alternate host, juniper, is near by, you can also prune out orange spore mass producing cankers on the junipers.
The fungicide thiram is not used in current practices. You can use chlorothalonil, available in stores as Fungonil or Bravo, or in a generic brand. You can also use a copper fungicide. The key is to apply in the spring, when new leaves and fruit are being formed, and the spores are being produced in those swellings on twigs or on old fruit. You may want to apply twice in the spring, about 10 days apart.

Thank you for contacting Cooperative Extension,


Thanks for the information. I have purchased the product 'Daconil' from Southern States. It contains chlorothalonil. I have sprayed the service berry trees once as the buds are beginning to open and will do so again in the next few days. I have noticed growths on some of the branch tips and will prune these off as well. I had service berries when I lived in Illinois which fed the birds there and I hope to do the same here in Delaware.

Hope you have good luck with your serviceberry trees and the bird watching! Do take care with the pesticides such as daconil and any insecticides for sure with the bees and birds. I would suggest spraying the trees once more at petal drop of the flowers, because bees would be finished then. That way the fruit can develop pesticide free for the birds. The fungicide residues probably last on surfaces about 7 days, depending on rainfall.

Thanks again for contacting Cooperative Extension,