More Weird Leaves On A Tree
Thank you for attaching the images. These are leaf galls cause by very small insects as the y feed on the leaf tissue.
The typical story is that the female adult lays her eggs on, or in, the back of the leaf; the larva (youngster) hatches and starts feeding on the leaf tissue. As the insect feeds, it injects salivary fluids which cause the leaf tissues to form as is shown in your images. Each insect species makes leaf galls specific to their kind. These appear to be needle galls. You can learn the name if you search online with “leaf galls plant name” – omit the quote marks and insert the tree’s name.
The number of leaves with galls will vary from one year to the next,this people the populationof the causal insects also varies.
Leaf galls are not detrimental to the tree’s health. Some people consider the galls an interesting part of nature while others think they are ugly and want them gone.
No treatment is suggested for this sort of leaf gall. If a few leaves are affected, you might want to remove them; if many are affected, you might as well allow them to remain.See “Galls on trees” - http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/other/galls/galls-on-trees.aspx
Thank you for this great answer. I did the search, leaf gall grape vines, as you suggested. The answer with a picture similar to mine is in the article at https://ask.extension.org/questions/146821
Thank you for the follow-up.
If you do another search, but on the internet and with your favorite search engine, you'll be able to find a perfect match. I used the phrase "leaf galls grape" -- but no quotes -- and found these images: https://www.google.com/search?q=leaf+gall+grapes&source=lnms&tbm=isch&sa=X&ved=0ahUK...#
Notice the several perfect matches on that page, including this close-up view: http://www.insectimages.org/browse/detail.cfm?imgnum=5472892