Synonyms: Cedar-Apple Rust, Juniper-apple Rust.
Cedar Apple Rust is one of many rusts, which are parasitic fungi that have two alternate host plants belonging to separate families. In our region, one of the host plants for Cedar Apple Rust is Eastern Red Cedar (Juniperus virginiana) and the other host is a plant belonging to the Rosaceae (Rose Family), such as apple, hawthorn (Crataegus species), or serviceberry (Amelanchier species). The rust is a major agricultural pest on apple and similar crops, whereas the cedars are relatively resistant.
Cedar Apple Rust overwinters on cedar trees as hard, dull-brown galls. In response to spring rains, the galls put out gelatinous (jelly-like) orange "horns." These bear spores that are carried by wind or insects to the leaves or fruits of alternate host plants. During dry spells, the horns of the galls on the cedar shrivel, to reawaken when it rains. The spores from the cedars cause the formation of small, dense, spore-case clusters on leaves or fruit of the alternate host. The spores released by these spore cases are disseminated and produce the galls found on cedars.
Cedar Apple Rust occurs throughout Maryland. It needs its two alternate host plants to be in relatively close proximity.
There are 402 records in the project database.
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