Eggs on leaves
I have multiple trees on my terrace and one in particular is blackening slightly and covered in white eggs/cocoons. There are lots of flies around and coming into the flat. Also, wasps seem to like it there too (the white eggs).
Certified GKH Gardening Expert
I would use Neem Oil to treat the plants.
Neem Oil is organic and safe for people and pets.
Here is a link with more information.