Cedar-quince blight - what to do?
I have an 8 or 9 year old quince bush, which last year gave very nice fruit in addition to blossoms. This year the fruit looked deformed and had black speckles on them....and now are covered what look like orange scales or dried droplets. There are wild crab apples in the area, as well as cedar/juniper trees, which is what made me wonder about that particular fungal problem. The setting is a city garden in a double lot in northern Baltimore City
Quince can be subject to several fungal diseases as well as quince rust. This rust fungi requires two types of plants, a pomaceous plant and a cedar in which to complete their life cycle. Juniperus virginiana, the Eastern red cedar, is the most common rust-susceptible cedar in Maryland. Fungal spores produced on one type of host plant are carried by wind to infect the other.
The best recommendation is to select resistant varieties. Practice good sanitation, remove any fallen fruits from the ground.
Removing the cedar/ juniper trees may not be practical. Controlling rust diseases with a spray schedule is difficult as you would have to spray in the early spring, bloom, petal fall, and cover sprays. http://extension.umd.edu/hgic/rust-diseases-trees-and-shrubs