This one is located at Campamento Mara. Fly into the area and destroy the growths. You have to destroy the entire growth before you die or it grows back. For the mushrooms, use the Air Lifter to lift them up before you take them out.
Next, you have to destroy the source. Use the retract to open the bulb and then shoot at the red. Repeat two more times for the achievement. If you die, you have to start destroying the source from the checkpoint (after destroying the growths).