What happens to the insects after the weeds are gone?
Sorry, but your weeds will never be eradicated. In the most successful examples of biological control there are always a small number of plants that do not fully succumb to the attack of the beneficial insect. This is good. It allows the insect population to sustain itself during years of low weed density.
Biological Control of Weeds, Inc.
1418 Maple Drive Bozeman, MT 59715