That gel like substance is Peach tree rust which is a fungal disease that affects peach
trees and other plants in the Prunus genus, such as almonds, apricots, cherries, nectarines, and plums.
Where I live we have
apple tree rust which is very similar to peach tree rust.
Juniper trees are carriers of the
apple tree rust.
I don1 know what causes peach tree rust other than fungal spore.
It can be treated with a fungicide.
We did not have any luck treating our trees so we got rid of them.