Hi, all nature lovers!
Today, walking through the forest, I saw strange balls on oak leaves. At first I thought it was some kind of "fruit". This surprised me, because I know exactly what oak "fruits" look like!
The thought of what happened to the tree haunted me! I decided to find out. Using Google Lens, I found similar images and started reading.
It turned out that these balls have a name oak apple or oak gall. The reason for their appearance are insect larvae. These insects are called "nutworms" or gall wasp. Moreover, the disease affects young trees. Indeed, the oak, the photos of which you see in this post, is still a very young plant.
But the most interesting thing is that these ink nuts used to be used to make ink! Even the ancient Romans used them for this.
In addition to oak, the gall wasp can lay larvae on roses, maple, mountain ash, as well as on herbaceous plants.
I was not able to find affected plants in nature, so I took pictures in the public domain on the Internet.
pic credit https://www.thoughtco.com/gall-wasps-family-cynipidae-1968088
pic credit https://mauget.com/glossary/cynipid-gall-wasps/
In fact, I often saw plants like the one in the photo above when I was a kid. Back then we called it "rust". But now I know they are insect larvae.