[Eric Vinje]

Hello Alice –

Juniper hawthorn rust and cedar apple rust are very similar plant pathogens that attack eastern red cedar and other varieties of juniper. Both are caused by fungal spores that require juniper plants to be present to exist. These spores overwinter as a reddish-brown gall on young twigs of various juniper species. In early spring, especially during wet weather, these galls swell and bright orange masses of spores are blown by the wind where they infect susceptible hawthorn, apple, crabapple and pear trees. To control this persistent disease we recommend the following:

• Rake up and dispose of fallen leaves and other debris from under trees.
• Remove galls from infected junipers. In some cases, juniper plants should be removed entirely.
• Use a thick layer of mulch to cover the soil after you have raked and cleaned it well.
• Prune or stake plants to improve air circulation.
• Water in the early morning hours or use soaker hoses to give plants time to dry out during the day — avoid overhead irrigation.

Note: Organic fungicides — copper and sulfur sprays — can be used to protect trees from spores being released by the juniper host in mid-spring. however, this occurs only once a year, so additional applications after this are not necessary.

https://www.planetnatural.com/pest-problem-solver/plant-disease/cedar-apple-rust/

Hope this helps!

[Author]

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