Field of Science

Quince rust?

Belette asks, "Do you happen to know anything interesting about Quince Rust?" (image)

Well, yes, and the most interesting thing the Phactor knows, in this particular instance, is that the image you sent the link for (above) shows quince scab, not quince rust. Scab is caused by a fungus called Venturia inaequalis. Cedar (actually Juniperus)-apple rust is caused by Gymnosporangium cavipes with its typical alternate host, lots of stages, terminology nightmare, rust life cycle. The quince scab also causes the leaf spots you mentioned. You can achieve some control over the scab fungus by removing the fallen infected leaves this fall which is where the fungus over winters. Spores are released in the spring to reinfect new leaves and fruit. It can be controlled at that stage by fungicidal orchard sprays too. So you won't have to cut down your neighbor's red cedars after all.

1 comment:

Belette said...

Thanks! That explains why my looking up quince rust didn't get me anywhere. And now I know the True Name I can find several other useful pages. Maybe there is something in this nomenclature thing after all.

I'll do a better job of sweeping up the leaves this year and see if that helps. Though I have neighbours a few doors away with a tree, and I can't do much about them.