I have spittle globs on almost every one of my plants, they are in containers. Is this from a spittle bug? Are they harmful, or just unsightly? Any treatment I should be doing to the plants in general to make them less palatable to these bugs? Any reason why this year they showed up in big numbers? Thank you. P.S. the picture was taken with little flip phone, so it's not the best, but gives you the general idea. Think of it as a watercolor or some art that is impressionistic. :)