Hello Margaret,

Thank you for your question.

I know this may sound odd, but I think what you are seeing is a fungus (note the resemblance to mushroom growth). At least that is what it looks like in the photo.

We are seeing a lot of issues with fungus because of the severe heat and humidity. To check to see if it is a fungus, rather than insects, break off a chunk of the growth and inspect it. Be sure to dispose of it in a bag and in the trash and wash your hands before touching any other parts of the plant or other plants. You should be able to determine, by the feel, if it is a fungal growth.

Here is a description from https://extension.psu.edu/holly-diseases of "Leaf Scorch" caused by sudden changes in the weather: "Young leaves formed during cool, damp weather are damaged easily if exposed to hot, dry, windy weather."

"Tiny, black fungal fruiting structures pepper the spot surface as a
result of attack by a secondary fungus."

Here is a website with tips on dealing with diseases of holly. If you type "fungus on holly," into your search engine, the "live to plant" site should show up with a photo at the top that looks very much like what you are seeing. For some reason, the photo does not appear when you go to the site. The site does, however, address how to treat it.

https://livetoplant.com/common-holly-plant-diseases-how-to-identify-and-treat/

If, on the other hand, it seems you are dealing with a pest and not a disease, here is a website that should be helpful:

https://livetoplant.com/most-common-holly-plant-pests-identification-and-treatment-guide/

I hope this is helpful and that your holly will recover.

Good wishes,