Knowledgebase

Apple Tree Leaf Issue #871586

Asked June 04, 2024, 5:15 PM EDT

Hello – We've nurtured a 6-in-1 espalier apple tree the past 10 years. This year, the leaves of the lhe lower-right "honeycrisp" branch have rapidly developed a "pimpled" appearance which seems to be spreading to the macintosh branch above it. Can you positively identify what might be going on from the attached images? If not, please let me know what I can provide to help identfy the issue, and what can be done to treat it. Thank you in advance for any guidance you can provide!

Deschutes County Oregon

Expert Response

Hi Mark,   Was there any use of an herbicide to manage for weeds?  If not, I suggest you bring a sample (Several leaves and stem) into our plant clinic so we can look at them under the microscope.  Could be environmental or could be  a small insect.  we are located on the Fairgrounds in Redmond and open M-F 9-4.  Once we can take a closer look we shoud be able to furhter assist and suggest management. 
Amy Jo Detweiler,  Professor and Extension Horticulturist Replied June 06, 2024, 7:06 PM EDT

Good morning and thank you Amy.  We have not used any herbicides, though I cannot speak for our neighbors and their landscaping/management on the other side of the fence.  We have had some fungi growth at the base of the wooden fence line in the past, but it was not near the apple tree.  I've done a reasonably good job gently removing the growths along with some of their root structure in the past.  I will try to get the requested leaf/stem sample up to you sometime today, Friday 6/7.  Thank you so much!

The Question Asker Replied June 07, 2024, 10:00 AM EDT

Hello, sorry to be a "pest" (hah, haa – just struck me as funny since we're trying to figure out what kind of "pest" we're dealing with...) but I dropped off the requested sample and spoke with ... (good with faces, bad with names,) Friday 6/7.  I was wondering whether you were able to determine anything looking at it under the microscope.

Thanks and regards,

Mark

The Question Asker Replied June 11, 2024, 4:02 PM EDT
Hi Mark,  I did take a look under the microscope but did not see anything,  I was primarily looking for mites that can sometimes appear that way.  In looking again, some of that damage really looks consistent with herbicide damage?  Is the newest growth showing symptoms or is it outgrowing the damage?  Here is what I was looking for was these blister mites, but did not see any?
https://extension.usu.edu/planthealth/ipm/notes_ag/fruit-blister-mites

If the leaf damage continues with new leaves you could consider sending a branch sample over to the plant clinic in Corvallis,  I believe the cost is $87 per sample.  
Amy Jo Detweiler,  Professor and Extension Horticulturist Replied June 14, 2024, 8:05 PM EDT

Loading ...