Fruit tree issues - Ask Extension
Hi. I was just wondering what might be going on with my Asian pears and plums and what I might need to do to address the problem. They seem to have ...
Knowledgebase
Fruit tree issues #870306
Asked May 27, 2024, 4:20 PM EDT
Hi. I was just wondering what might be going on with my Asian pears and plums and what I might need to do to address the problem. They seem to have some type of bugs or disease. See attached photos.
Montgomery County Maryland
Expert Response
Hi-
Asian pear: this is a classic symptom of rust (possibly quince or hawthron rust), a fungal disease named for the orange spores and leaf lesions it produces. Many plants in the rose family (apple, pear, crabapple, hawthorn, quince, serviceberry, etc.) can contract rust and the fungus has unusual reproduction where it must spend part of its life cycle in another unrelated host plant, in this case, juniper (such as our native and widespread Eastern Redcedar). You can learn more about rusts in this Ohio State University article.
Fungicide treatments sometimes help prevent rust infection but they must be applied at bloom. Several reapplications each season may be needed to effectively suppress the disease, and once symptoms manifest, as they are here, no treatment will be effective because these spores are intended to infect the juniper host again to complete the cycle. Fungicides will also not be able to cure an existing infection or reverse its effects. Ideally, the most practical approach to dealing with rust since it's such a widespread disease is to select cultivars. Unfortunately, there are no rust-resistant Asian pear cultivars.
Not much needs to be done at this point since these spores are windblown and abundant enough (from infections on other wild and cultivated trees) that removal of these won't make much difference. Still, you can pluck off and dispose of any infected fruits that you can reach if you prefer. We recommend that backyard fruit growers use spray schedule information from Virginia Extension (click Home Fruit in right sidebar).
Note: organic fungicides like sulfur are not very effective against rust. Mancozeb is a synthetic fungicide labeled for controlling rust diseases in pear trees.
Plum: this symptom is consistent with brown rot, a very common fungal disease of peach, cherry, and plum. Infected fruits will shrivel and become fruit "mummies," covered in gray to tan spore masses.) Strip off and remove all affected fruits from the tree and the ground. Use prevention and management information from the Virginia Extension fruit management guide.
If brown rot is not the cause, one or more plant stressors (e.g. extreme weather, poor tree health) may have caused the brown fruit discoloration.
Jon
Asian pear: this is a classic symptom of rust (possibly quince or hawthron rust), a fungal disease named for the orange spores and leaf lesions it produces. Many plants in the rose family (apple, pear, crabapple, hawthorn, quince, serviceberry, etc.) can contract rust and the fungus has unusual reproduction where it must spend part of its life cycle in another unrelated host plant, in this case, juniper (such as our native and widespread Eastern Redcedar). You can learn more about rusts in this Ohio State University article.
Fungicide treatments sometimes help prevent rust infection but they must be applied at bloom. Several reapplications each season may be needed to effectively suppress the disease, and once symptoms manifest, as they are here, no treatment will be effective because these spores are intended to infect the juniper host again to complete the cycle. Fungicides will also not be able to cure an existing infection or reverse its effects. Ideally, the most practical approach to dealing with rust since it's such a widespread disease is to select cultivars. Unfortunately, there are no rust-resistant Asian pear cultivars.
Not much needs to be done at this point since these spores are windblown and abundant enough (from infections on other wild and cultivated trees) that removal of these won't make much difference. Still, you can pluck off and dispose of any infected fruits that you can reach if you prefer. We recommend that backyard fruit growers use spray schedule information from Virginia Extension (click Home Fruit in right sidebar).
Note: organic fungicides like sulfur are not very effective against rust. Mancozeb is a synthetic fungicide labeled for controlling rust diseases in pear trees.
Plum: this symptom is consistent with brown rot, a very common fungal disease of peach, cherry, and plum. Infected fruits will shrivel and become fruit "mummies," covered in gray to tan spore masses.) Strip off and remove all affected fruits from the tree and the ground. Use prevention and management information from the Virginia Extension fruit management guide.
If brown rot is not the cause, one or more plant stressors (e.g. extreme weather, poor tree health) may have caused the brown fruit discoloration.
Jon
