Bartlett pear tree brown, wilted leaves - Ask Extension
Hi. I thought you had an article recently in your paper publication (Benton County) about pear blight last month, but I can't seem to find it here onl...
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Bartlett pear tree brown, wilted leaves #144080
Asked July 30, 2013, 4:50 AM EDT
Hi. I thought you had an article recently in your paper publication (Benton County) about pear blight last month, but I can't seem to find it here online. I recently (late July) noticed our Bartlett pear tree has several branches with dark brown, wilted leaves. There are brown spots on many other leaves. The tree started dropping some leaves a month or two ago. I'm thinking based on photos I found on line it is fire blight? Please help! What should I do about it?
Polk County Oregon
Expert Response
It looks like you have two separate problems from the pictures you sent. One is a bacterial leaf spot, which is controlled by pruning and a series of dormant sprays of either sulphur or copper. You could also use a Bordeaux mixture which you have to mix yourself. UC Davis IPM has a great paper on this. The other flagging of whole branches might be fire blight. Refer to PNW Plant disease handbook for controls. Definitely prune out infected branches and destroy them.
Thanks, Jeffrey. It looks like Bordeaux 8-8-100 is recommended for fire blight on pears, so would that would help with both conditions as a dormant spray? Or does the fire blight have to be sprayed on the blossoms, not on the dormant tree?
Also, can you tell me if 2013 is a 'fire blight year' in the Willamette Valley? The PNW guidebook you steered me to says it's rare here, but maybe that's changing. Other options of what might be causing the limb dieback are not all included in the guide (so I'm not sure how to distinguish or is the treatment similar?). They include:
"Pseudomonas blossom blast, Nectria twig blight, pear dieback caused by Phomopsis sp., and twig borer beetle damage"
I also read that young shoots and wood are most susceptible, but in our tree, it's the older branches that are dying. Does this help make a determination, or if wood is too old, is it also susceptible? (The tree is well over 30 years old.)
Thanks again.
Also, can you tell me if 2013 is a 'fire blight year' in the Willamette Valley? The PNW guidebook you steered me to says it's rare here, but maybe that's changing. Other options of what might be causing the limb dieback are not all included in the guide (so I'm not sure how to distinguish or is the treatment similar?). They include:
"Pseudomonas blossom blast, Nectria twig blight, pear dieback caused by Phomopsis sp., and twig borer beetle damage"
I also read that young shoots and wood are most susceptible, but in our tree, it's the older branches that are dying. Does this help make a determination, or if wood is too old, is it also susceptible? (The tree is well over 30 years old.)
Thanks again.
well, you have mentioned four pathogens, two fungi and two bacteria. The controls for all of them are similar with slight variations in application. For fire blight you DO need to apply spray to the blossoms in the spring. This means that you want to do it in the afternoon when the bees are gone. We certainly don't want to kill any more bees. But fire blight is still quite rare in the Willamette Valley. It's the one disease we don't see much of.
Pseudomonas blossom blast would have exhibited signs much earlier. Nectia is identified by sunken cankers on the twigs. Phomopsis mainly infects the fruit.
The link for the bordeaux mixture is www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7481
Stress of the trees often brings on these diseases so be sure your trees are well watered. Pruning whenever you see infected tissue will go a long way into the trees recovery.
Pseudomonas blossom blast would have exhibited signs much earlier. Nectia is identified by sunken cankers on the twigs. Phomopsis mainly infects the fruit.
The link for the bordeaux mixture is www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7481
Stress of the trees often brings on these diseases so be sure your trees are well watered. Pruning whenever you see infected tissue will go a long way into the trees recovery.
