Earleaf Acacia
Acacia auriculiformis A. Cunn. ex Benth (Fabaceae), commonly known as earleaf acacia is an fast-growing, evergreen tree native to Australia, Papua New Guinea, and Indonesia. Earleaf acacia comes from mesic and humid subtropical forests, where it naturally grows along riverbanks and other high-water table areas. Earleaf acacia can be found in swamp forests and can tolerate a wide range of poor soils. This plant was introduced in Florida as an ornamental plant in the early 1900s. Since then, earleaf acacia has become a serious plant invader in Florida. This plant continues to spread at an alarming rate in southern and central Florida. Efforts to understand its current distribution and possible range in the USA are underway.
The current control methods for earleaf acacia are hand pulling seedlings, removing mature trees, and using herbicides. Our goal is to develop a biological control program to be integrated with the control methods for earleaf acacia in Florida, so that we may slow the spread of the plant and reduce negative environmental and economic impacts in the US
Earleaf acacia leaves and flowers (left) and fruits (right). Photos by: Sara Salgado.
Insects currently under study for potential use as biological control agents for earleaf acacia
Calomela intemerata
Calomela intemerata (Coleoptera: Chrysomelidae), a promising candidate for the biological control of earleaf acacia, has been undergoing host range and climate suitability testing at two containment laboratories in Florida since 2019. Colonies of two biotypes, Queensland and Northern Territory, are maintained at the Hayslip Biological Control Research and Containment Laboratory.
Calomela intemerata. Photo by: Sheri Holmes
Trichilogaster sp. nov.
Trichilogaster sp. nov. (Hymenoptera: Pteromalidae) is an orange, bud-galling wasp. This tiny wasp produces bud and stem galls on infested earleaf acacia plants. Little else is currently known about this species. This wasp species is currently undergoing identification by taxonomists as well as host range and biology studies to ensure its safe use as a biological control agent for earleaf acacia. It is well documented that the wasps in the genus Trichilogaster produce galls on Australian acacias and are highly host specific. There are two other species that are successful biological control agents of acacia species in other parts of the world, Trichilogaster acaciaelongifoliae Froggatt and Trichilogaster signiventris Girault. Therefore, potential success with using this new species of Trichilogaster for control of earleaf acacia in Florida is high.
Trichilogaster sp. nov. adult (left) and galls (right). Photos by: Sara Salgado.