Queensland
Guides
Samea multiplicalis
salvinia stem-borer moth
Samea multiplicalis is an aquatic moth native to the Americas, ranging from the southern United States to Argentina, and introduced to Australia in 1981 as a biological control agent for invasive water ferns. Adults are small, tan moths with darker wing markings and a wingspan of approximately 20 mm. The species completes its entire life cycle on or near aquatic host plants, with larvae feeding internally on stems and externally on leaves, often causing plant death. High rates of parasitism by native wasps and flies limit its effectiveness as a weed control agent in introduced ranges.