 Cedar-apple
rust: Cedar-apple rust is the most important rust of apple in eastern North America.
The fungus can infect leaves and fruit of most cultivars in the mid-Atlantic region. A
notable exception is 'Delicious', which is nearly immune. The disease is prevalent
wherever the alternate host, eastern red cedar (Juniperus virginiana L.) occurs. On
susceptible cultivars it can cause serious crop loss, reduction of crop value, as well as
almost total defoliation. Two other rusts, quince rust and hawthorn rust, can be
significant problems in some areas in some years, depending upon availability of alternate
hosts and environmental conditions.Management: Fungicides that are effective against the rust diseases should be applied periodically from the pink stage of bud development through third cover to protect the emerging leaves and developing fruit. Removing cedars located within a 2-mile radius of the orchard interrupts the life cycle of the fungus and makes control with fungicides easier. Removing all cedars within 4 to 5 miles of the orchard will provide complete control. Cedar removal is not a practical option for most commercial orchardists. |