Eggs?

Eggs?

Observation - Eggs?. Description: These orange things, about the size of slugs eggs were found in the bottom of a plastic tree guard round a 3 year old plum tree. The tree had been mulched with bark. Most were a light orange and wrinkled. They were hard but when squeezed they popped and h

These orange things, about the size of slugs eggs were found in the bottom of a plastic tree guard round a 3 year old plum tree. The tree had been mulched with bark. Most were a light orange and wrinkled. They were hard but when squeezed they popped and had a small amount of white substance in them. Others (a few) were not wrinkled, were darker orange, of matt appearance, and would not pop when squeezed. Any ideas? They were on the surface, not underground.