State proposes introduction of moth to control invasive fireweed plant

The Hawaii Department of Agriculture (HDOA) proposes the introduction of a moth (Secusio extensa) into Hawaii as a natural enemy and biological control agent for the fireweed plant. Fireweed is an invasive plant that is toxic to livestock, and quickly infests heavily grazed or neglected pastures, and even cultivated land.

Courtesy Photos by Ron Heu, and Walter Nagamine, (Hawaii Dept. of Agriculture).

Secusio extensa male moth. Photo courtesy Hawaii Department of Health.

The release of the moth is expected to reduce fireweed populations to manageable levels.  Studies were conducted on more than 70 plants considered to be key components of Hawaiian ecosystems.  Tests showed the moth was host specific to a tribe of plants that does not include any native or economically important plant species in Hawaii.  The one exception was the Helianthus anuus, an introduced plant, which researchers found could not sustain a population of the moth.

Release of the moth is proposed on Maui, Oahu and the Big Island.