Rust spots on my Bartlett pear tree - Ask Extension
Hello, I have rust spots on my Bartlett pear tree. And I don't see any fruits on it. It is a relatively young tree 4 yrs old. What should I do.?
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Rust spots on my Bartlett pear tree #877374
Asked July 15, 2024, 6:27 PM EDT
Hello, I have rust spots on my Bartlett pear tree. And I don't see any fruits on it. It is a relatively young tree 4 yrs old. What should I do.?
Benton County Oregon
Expert Response
Hi, Sharna,
Pears can be slow to begin bearing fruit. Did it bloom this spring? If it didn't, that is why no fruit. If it did, there could be a pollination problem. The weather might not have been conducive to pollinators flying, or a freeze could have damaged the blooms.
If it bloomed and there were very tiny fruits that aborted, other things could be happening - including rust infecting them when they were young. To tell what is happening for sure, you'll need to observe the tree carefully as soon as it starts to flower or produce leaves, next spring.
Rust is a common disease of pears, and there are two kinds in the PNW. Pear trellis rust https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-trellis-rust-european-pear-rust and Pacific Coast Pear Rust https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-pacific-coast-pear-rust. A small amount is not usually a big problem, but in a bad year it can be quite damaging. Juniper or incense cedar are alternate hosts for the fungi, and since most neighborhoods have one or the other, it is hard to avoid it completely. However if you can remove any junipers (or incense cedars) within a 1,000ft radius, that is the best way to break the cycle.
If you can remove and bag infected leaves, that can deter a young infection - but only temporarily if there is an alternate host nearby. However, it looks like you may already have many leaves infected.
There are few non-commercial fungicides available to homeowners for rust. The PNW Handbook suggests Immunox for flowering pears. The
Pesticide Information Center Online (PICOL) Database list other possibilities for home use, such as sulfur and neem oil. These can be used to prevent infection early in the season. They must be applied at the right time - read the label for application instructions. As with any fungicide, they cannot prevent an active infection, only reduce further infection.
Pears can be slow to begin bearing fruit. Did it bloom this spring? If it didn't, that is why no fruit. If it did, there could be a pollination problem. The weather might not have been conducive to pollinators flying, or a freeze could have damaged the blooms.
If it bloomed and there were very tiny fruits that aborted, other things could be happening - including rust infecting them when they were young. To tell what is happening for sure, you'll need to observe the tree carefully as soon as it starts to flower or produce leaves, next spring.
Rust is a common disease of pears, and there are two kinds in the PNW. Pear trellis rust https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-trellis-rust-european-pear-rust and Pacific Coast Pear Rust https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-pacific-coast-pear-rust. A small amount is not usually a big problem, but in a bad year it can be quite damaging. Juniper or incense cedar are alternate hosts for the fungi, and since most neighborhoods have one or the other, it is hard to avoid it completely. However if you can remove any junipers (or incense cedars) within a 1,000ft radius, that is the best way to break the cycle.
If you can remove and bag infected leaves, that can deter a young infection - but only temporarily if there is an alternate host nearby. However, it looks like you may already have many leaves infected.
There are few non-commercial fungicides available to homeowners for rust. The PNW Handbook suggests Immunox for flowering pears. The
Pesticide Information Center Online (PICOL) Database list other possibilities for home use, such as sulfur and neem oil. These can be used to prevent infection early in the season. They must be applied at the right time - read the label for application instructions. As with any fungicide, they cannot prevent an active infection, only reduce further infection.
