Three of my tuscan blue rosemary plants (I have 5, all getting same sun and water) have started to dry up and die off, one branch at a time. Half of three of the plants are close to dead, the other branches of those plants are starting to look sick too.
I just noticed small little light green flying insects (very small, sort of triangular in shape) that fly off the sick plants when I water. What are those insects and how can I control them. Are the insects killing the rosemary plant, or are they there because of the dead plant?