In “The War of the Worlds” the gross alien invaders — Martians, of course — ravage the cities and countryside alike, only to fall victim to the ordinary microbes swirling around in the air. Tiny things save the day.

Now, insects are helping garden-gloved human hands — and their accompanying trowels and loppers and weed whackers — in fighting against the hoard of non-native running-wild plants that can smother the local greenery.

Imported leaf-eating beetles have helped keep purple loosestrife from taking over the state’s wetlands. Imported weevils that feed exclusively on mile-a-minute vine — named for the speed at which it grows — now seem to showing up wherever the plant takes root.