Pear leaf curling not midges

Question: I have an asian pear tree, about 10 years old, that suddenly had an issue when leaving out. Pointy, skinny, curled leaves - similar to rose rosette. It has affected a few branches of both apple trees - about the same age. After ruling out midges (no bugs anywhere) I did find a similar picture talking about zinc deficiency. After spraying with zinc I noted some of the new leaves looked closer to normal (second pic). Any other ideas? Thanks!

responder: Rhonda Frick-Wright  Replied June 05, 2023, 9:54 PM EDT
response: Hi Oliver and thanks for your question and great pictures of your Asian Pear tree leaves. What this really looks like to me is chemical damage. Did anyone spray an herbicide anywhere near the trees? The wind has been high lately and blows the chemicals easily into the air. This causes curled deformed leaves.  This can also happen if the lawn was sprayed with an herbicide even in winter. This can also happen if the same sprayer was used with an herbicide and then an insecticide or fungicide.   The only other thing likely to cause this deformity is powdery mildew which you would see as a white to gray powdery growth on the leaves or shoots.   The only think you can do at this point is keep the proper culture, ie water and sanitation for the tree this summer and keep fingers crossed. If it IS an herbicide incident, I would not eat the fruit this year.  https://s3.wp.wsu.edu/uploads/sites/2071/2013/12/Growing-and-Using-Asian-Pears.pdf

responder: The Question Asker Replied June 06, 2023, 6:54 PM EDT
response: Thank you for the reply - very appreciated! I really doubt it would be a chemical herbicide. The only thing I use on / around this tree is Neem oil (from concentrate) with a little liquid soap so it sticks. I have used it for a few years to control... powdery mildew of course! It is possible that it is powdery mildew. It is close to the grape arbor that does get it every year, but with the Neem oil for the past few years it has been kept well under control.  Also, I did spray the Neem oil as the initial "hope for a cure" this spring when I saw it. It doesn't seem to be the powdery mildew but if you don't think it could be a zinc deficiency I will assume it is the powdery mildew and continue accordingly. The only two things we spray with are potent vinegar to help in the fight against weeds, and Neem oil to assist specifically with powdery mildew. Any other thoughts? Attached are two photos of one stem off of the Arkansas Black that has suffered similarly, one from above and one from below. There is also one pic from a pear "rosette" I harvested. LMK if there is anything else that you think could have caused this :)

responder: Rhonda Frick-Wright  Replied June 06, 2023, 8:00 PM EDT
response: Hi Oliver- I have tried reassigning this question to an Oregon State expert on diseases to see if he can find any other options. If you don't hear from someone in a week, let us know. Good luck,

responder: Jay W. Pscheidt, PhD, Professor  Replied June 07, 2023, 9:29 AM EDT
response: Sorry, but I have to agree with the first impression of a chemical injury.  This is not powdery mildew. The fuzzy growth you show in some of your images is just normal trichomes of the leaves.  One of the things that is not apparent from the images is the distribution of the damage. It seems like it is on some branches but not others but maybe it is on all the branches. Plants in the background (fig tree?) do not seem to have any issues.  The key image is the third one where we see fruitlets that are beginning to size right along with rosetted shoot buds. This indicates that whatever the issue is, it occurred after or near the end of flowering.  Multiple rosetted shoots coming from the same node tends to indicate use of glysophate in preceding years. I know you have not used anything like it but it is very similar.  The injury may also be due to chemical use after flowering. I do not know that neem oil would do this. There are warnings on the label about using it on tender foliage. I would not use the soap in the product as neem oil will spread just fine without it. Use during the usual heat spell we had this spring can also be the cause. Plants were not adapted to the heat at that time. So, review the date of your applications, any changes in the products you used and the weather at those times.  Low on the list of issues could be a virus but I am not aware of which ones it might be or why it would show up after 10 years.