I noticed on some of the leaves of my azaleas there are semi-hard white "foamy substances" growing on the leaves and want to know what it is and how to treat. Thank you.
Certified GKH Gardening Expert
It sounds like spittle bugs to me. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/insects/spittlebug-control.htm