My pears have rust, what can I do?


Yes, your pear tree is infected by Pacific Coast Pear Rust. (If it's any consolation, many other pear trees in our region also have rust this year.) Significant outbreaks occur every several years. Both Asian and European cultivars are susceptible. 'Winter Nellis' is severely affected whereas 'Bartlett' is typically less affected. Some years, ‘Bartlett’ can also be seriously affected. Most rust diseases are interesting in that they require two hosts to complete the life cycle. With Pacific Coast Pear Rust the alternate (2nd) host is incense cedar. At the time pears were in flower, bright orange telia (jelly-like blobs; the fungus) were on the infected cedars. (See attached image.) Airborne spores from the jelly masses infect susceptible pears, both flowers and leaves. In order for a spray to be effective, it must be applied when the swollen, orange telia are present on the cedars. In western Oregon, that’s usually during bloom. (In other words, it’s too late to spray this year.) Another glitch is that suggested products are available only to commercial pest control companies. (If you may hire a company, consider reviewing “Selecting a Pest control Company”. Do not apply pesticide to the soil. It won’t affect rust. Your strategy for the remainder of this year will include (1) good sanitation (collect and discard infected leaves and fruit); (2) remove and discard any infected woody parts; and (3) if the incense cedar is on your property, consider removing it.

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