Recipient Organization
AGRICULTURAL RESEARCH SERVICE
(N/A)
FORT LAUDERDALE,FL 33314
Performing Department
(N/A)
Non Technical Summary
(N/A)
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Goals / Objectives
Earleaf acacia, Acacia (A.) auriculiformis Cunn. ex Benthe., is an increasingly problematic invasive tree in Florida. In its invaded range, A. auriculiformis inhabits similar habitats as Melaleuca quinquenervia (Cav. ) S.T. Blake in central and southern counties in Florida, but recent observations indicate the species is expanding northward. Earleaf acacia is an evergreen tree that grows to 15 m in height, displaces native vegetation and threatens to shade-out rare plants such as the nodding pinweed, Lechea cernua Sm. in remnant scrub areas (Langeland and Craddock Burks 1998). This distinctive species is recognized for long narrow leaves that are slightly curved with parallel veins (3-7). The fruit are flat, oblong pods that are twisted at maturity. Earleaf acacia was introduced in Florida in 1932 and commonly grown as an ornamental for street landscaping for many years (Morton 1985, Gordon and Thomas 1997). Earleaf acacia is listed as a Category I invasive by the Florida Exotic Plant Pest Council ((FLEPPC) Plant List Committee 2009) because it invades pinelands, scrub and hammocks of south Florida, including the threatened rock pineland habitat. Category I invasive species are those that cause significant negative ecological and economic harm by displacing native species and diminishing ecosystem services. Earleaf acacia (A. auriculiformis) naturally occurs in Australia, Papua New Guinea and Indonesia (Boland et al. 1990). Researchers with the Australian Biological Control Laboratory (ABCL) began surveys for biological control agents of earleaf acacia during 2015-2016. As part of the original studies to determine feasibility of biological control for A. auriculiformis, researchers at IPRL and ABCL conducted a series of field surveys, molecular analyses, and literature reviews. Earleaf acacia appears to be a viable candidate for biological control due to the abundant and diverse assemblage of herbivores discovered in its native range. Expanding this project will not only facilitate surveys into new, unexplored areas, during different seasons, but also the collection and initial host-range testing of potential agents. Objective 1: Conclude Next Generation Sequencing on samples of A. auriculiformis from the native range and Florida to determine the origin of the Florida invasive plant. Objective 2: Continue herbivore surveys in Northern Territory, Queensland for potential biological control agents. Objective 3: Ship, curate and colonize most promising insects from foreign surveys at ABCL, Australia, IPRL, Fort Lauderdale, and UF-IFAS IRREC, Fort Pierce, Florida. Objective 4: Begin initial host-range examinations at USDA-ARS IRPL and UF-IFAS IRREC.
Project Methods
Genotyping of Acacia Populations. The selection of biological control agents for the biological control of A. auriculiformis is likely to be influenced by the origin of the weed, which has a wide native distribution in Australia, Papua New Guinea and Indonesia (Boland et al. 1990). Sourcing insects from the origin of the populations in the introduced range can lead to a higher degree of success because these species may be better adapted to local conditions and ultimately, more damaging (Kniskern and Rausher, 2001;Â Goolsby et al., 2006). In its native range this species rapidly expands into new areas but its distribution is thought to be limited by aridity (Boland et al. 1990). Due to its wide use in horticulture, herbarium records exist for A. auriculiformis from Australia, (Northern Territory, Queensland), China (Fujian, Guangdong, Guangxi and Zhejiang), Indonesia, Papua New Guinea, India, Malaysia, Mauritius, Moluccas, Pakistan, Panama, Reunion, and Tanzania (Tropicos.org 2015). To determine the origin of A. auriculiformis, and potentially the number of introductions to Florida, we have employed Next Generation Sequencing (NGS) tools such as Genotyping by Sequencing (GBS) (Elshire et al. 2011). This now offers the ability for small projects with limited resources to obtain thousands of Single Nucleotide Polymorphisms (SNPs) for genotype analysis. Host Range Testing of Potential Agents. All potential agents will be shipped into permitted quarantine facilities. Due to the potential immediate need for better control for this species, we are approaching this candidate plant with a plan to test agents at the USDA-ARS IPRL facility and the UF-IFAS IRREC facility. This will safeguard against colony collapse and may facilitate a more efficient testing process due to the increased host-range testing required for compliance with Section 7 of the Endangered Species Act. For the first year, the plant acquisition funds will be split between UF and USDA and in subsequent years, requested funds will be utilized to support technicians and both quarantine facilities for host-range testing.