It is not webworms! Webbing on the bark of trunks and branches is a good thing. Don’t spray!! Bark lice is natures clean-up crew. These tiny creatures are scouring the bark for plant, animal, or fungus life which they eat, and while they perform this housekeeping chore, they spin this web for protection. Usually the web will disintegrate in two or three days and will disappear almost a suddenly as it appeared. Leave them alone and let them do their job of cleaning up your trees or shrubs. Thank goodness for good bugs!