Asian pear tree disease problem - Ask Extension
We have a roughly 30 year old asian pear tree that in the last three years has increasingly looked diseased with blotchy leaves. Almost all the leaves...
Knowledgebase
Asian pear tree disease problem #715076
Asked August 19, 2020, 12:41 AM EDT
We have a roughly 30 year old asian pear tree that in the last three years has increasingly looked diseased with blotchy leaves. Almost all the leaves are deteriorated now. Many of the branches have turned black and some of the smaller new branches have died. While there were new pears early in the season, almost all of them no longer exist. However, there is recent new growth at the top of the tree and sporadically throughout the tree. We have never sprayed the tree. We would like to know what is the disease, what can be done about it, and is the disease likely reversible or will it kill the tree? For health reasons we do not want to personally spray the tree if that is the desired way to get rid of the problem. What specific credentials or experience should we search for when looking to hire someone to do the spraying?
Multnomah County Oregon
Expert Response
Wow, we have not seen trellis rust this bad on any pears yet. The disease was first found in Oregon in 2016 but only on sporadic leaves here and there on a tree. I have seen more this year than in past years indicating it was very favorable for disease development. But my various fruiting pears here in Corvallis do not look near this infected.
Do you know any more about the type of Asian pear you have? My references are all boxed up due to a move we are making to a new building and Covid-19 issues, etc....Otherwise I could look up more about this on Asian pear. In the mean time, here is our section on this disease:
Now, I would be remiss if I did not mention fire blight as a possibility based on your description. Not as likely given the images but possible. The tree will survive both of these problems but fire blight has the capacity to kill the tree with disease reoccurring in back to back years. Based on your comments I suspect the rust will occur next year as well but weather will dictate how bad it might get. Any junipers near by or underneath the tree? It is the alternate host spreading the rust fungus.
Thanks so much for your quick reply. Our records are a bit confusing, but our tree is either a Hosui oriental pear or a Shinko, although we think it is the former. I checked the backs of the leaves and they are more blistered. I should also note that there is more new growth recently than I had earlier observed throughout the tree. My wife has decided we would like to spray, but given the great number of possible sprays it is impossible for us to choose which one would work best and be safest. Can you recommend one for us? Thanks again for your help. And if you would like to publish or publicize our tree problem, you’re more than welcome to do so.
Just let the tree service company make the selection based on what they have and use regularly. Most of them will do fine and none are available to you as a home gardener but the commercial care companies can get them.
Are there junipers under the tree? They might be contributing to the problem.
No, we do not have any juniper. Are you recommending that we hire someone to treat the tree rather than trying it ourselves?
Sometimes our interpretation of each others words is not the same. Lets try again on this topic:
If you wish to spray a fungicide to manage this rust disease on your Asian pear tree then all I can recommend is Bonide Fruit Tree and Plant Guard RTS which is registered but also contains an
insecticide in addition to a group 7 + 11 fungicide. There just is not a lot registered on pear for the home garden.
If you wish to hire a spray service to do the work, they can get similar products that might be more effective (and without the insecticide). Considering the age of your tree, they should be able to cover it better as well.
From your response it sounds like getting a spray service is the best approach. In looking locally on the Internet for such a service, what keywords would you suggest we use to locate such a service. Even better, can you give us any recommendations? As with all businesses, it is often very hard to decide which is the best company for a particular job. Again, our sincere thanks for your great help in solving this problem for us. George and Dawn Tsongas
Rating these services is not something we do. I would recommend, however, to get your usual 3 estimates and go with the folks you like better. There is no hurry as applications will no go on until next spring. There is not much you can do this year other than look for local Junipers that might be continuing the problem.
