I believe I have spittle bugs because there is foam on the stems of my plants but the top leaves are shrinking up and the base of the plant is dying. Could there be another bug? On a neighboring plant I'm getting brown spots on the leaves so there is yet another insect.
Spittle Bugs and ?
Certified GKH Gardening Expert
The following article should be of some help with the spittle bugs: https://www.gardeningknowhow.com/plant-problems/pests/insects/spittlebug-control.htm
As for the brown spots on the leaves of the other plant, if you are not seeing any signs of insects or other damage, then it is likely a fungus (there are several that create brown spots) and should be treatable with fungicide. I recommend neem oil, which is both an effective pesticide and fungicide.