A Study on the Natural History of Cytisus on Santa Catalina Island with an Emphasis on Biological Control

Exotic introduced species can disrupt native ecosystems and be particularly devastating on islands. Two brooms, Dyers' greenwold (Cytisus linifolius) and French broom (C. monspessulanus) (Fabaceae) may potentially outcompete native and endemic species on Santa Catalina Island. Re-establishment of these introduced invasive weeds is rapid following fire and disturbance. Seeds of these species may lay dormant in the soil for several years, although experiments show that abrasion of the seed coat enhances germination response. Phytophagous larvae of the Genista moth (Urcsiphita reversalis) (Lepidoptera: Pyralidae) are showing considerable promise in controlling the weeds and could be considered in the future for biological control.