I have these strange round brown things on my peach tree. they can't be insect eggs because they have the size of a lentil. they are white and sticky inside.
These seem to be Scale insects, you see the scale which protect the insects inside them.
They eats the sap. If they are active, usually you find ants nearby, taking part of the sap.
There are many types of such insects, with a lot of colours. These are very large, compared what I usually see.
Insecticides which enter to sap helps. You can remove them and then heavy water them. Without scale they are not a lot of probability to survive. Fighting ants also help: such insects are often the pet animals of ants: ants take care and carry them.