RJ, sure you're not thinking of cedar-apple rust regarding junipers?
Cedar-apple rust info:
http://www.ipm.iastate.edu/ipm...
"Cedar-apple rust is an interesting disease. It requires both an apple and cedar or juniper to complete its life cycle. On the cedar, the fungus produces reddish-brown galls that are up to golf-ball size on young twigs. During wet weather these galls swell and begin to push out bright orange gelatinous tubular structures. Wind carries fungal spores from these gelatinous structures to susceptible apple or crabapple cultivars."
Apple scab info:
http://www.apsnet.org/edcenter...
From the above, hosts of apple scab (pathogen Venturia inaequalis):
"Apples and flowering crabapples (Malus spp.), hawthorn (Crataegus spp.), mountain ash (Sorbus spp.), firethorn (Pyracantha spp.), and loquat (Eriobotrya japonica). Pear (Pyrus spp.) is infected by a related fungus, Venturia pirina, which causes nearly identical symptoms."
