Fireweed (Senecio madagascariensis Poiret) is one of 1200 species of Senecio distributed throughout the world.  A native of Madagascar and South Africa, it has spread to Australia, South America, and became established in Hawaii during the early 1980's.  Individual fireweed plants produce nearly 30,000 seed that remain viable for years.  When introduced fireweed quickly spreads and threatens agriculture operations.  Fireweed has infested nearly 100,000 acres of rangelands in Maui and Hawaii counties in less than 20 years.  In some areas, nearly 60 percent of vegetative cover is fireweed.  Senecio species contain hepatotoxic pyrrolizidine alkaloids (PAs) that if consumed induce irreversible liver damage.  There are few publications on the ecology and management of fireweed and until recently, none reporting the PA content.  Our recent research in Hawaii found that fireweed does contain PAs and that their concentration varied between collection locations.  From this preliminary research we hypothesize that PA concentration varies in fireweed across soil fertility, elevation, and climatic gradients. Anecdotal evidence indicates that rotational and multi-species grazing using sheep in particular can greatly reduce fireweed infestation in pastures.  We suggest an adaptive management strategy for the implementation of an integrated weed management program to control fireweed populations.  The adaptive management process, as it relates to fireweed control, involves: 1) establishing overall goals for the operation, 2) setting management priorities in relation to fireweed’s affect on operational goals, 3) identifying appropriate methods for the control of fireweed, 4) developing and implementing an integrated weed management plan, 5) monitoring results of management actions, and 6) modifying and improving the management plan accordingly.  Such an approach to fireweed control allows for flexibility in planning and priorities as conditions change.