Q: I live in Levy County, Florida, near Gainesville.
We have agapanthus under live oak trees and in beds with hydrangeas and azaleas mulched with pine straw and nightly irrigation, as we have high, dry sandy soil.
Yesterday the agapanthus were covered with insects which were literally decimating the plants before my eyes.
Description: About 3/4″-1″ in length with a silver gray body and almost black wings. The silver line shining in between its wings on its back gave an appearance–at first glance–of having a white stripe down its back. Upon further investigation, it appears that it is the silver-gray color of its body shining through.
They did not fly when I was near but kept intently eating away at the agapanthus leaves right down to the center stem/vein.
A: Lyle Buss, in the University of Florida Insect Identification Laboratory says it is a blister beetle in the genus Epicauta: http://entomology.ifas.ufl.edu/creatures/urban/medical/blister_beetles.htm
Don’t grab the beetles when they are alive! For control information, you could check out this article: http://edis.ifas.ufl.edu/IG013
Blister beetles have a strange life cycle, as the first article above describes briefly. The larvae of Epicauta eat eggs of grasshoppers, and could therefore be considered beneficial! The adult stage is the one that can be damaging to plants, as you already know.