Search

Pre-release efficacy assessments (PREAs) are used in weed biological control to predict the potential impact of prospective agents. These assessments enable the most damaging agents to be prioritised for host testing and release. Further, the inclusion of this information in release applications enables regulators to consider the benefits of an agent alongside any risks. We conducted a PREA to evaluate the efficacy of Trichilogaster sp., a galling wasp that is being considered for release in Florida to control invasive earleaf acacia, Acacia auriculiformis. This species is multivoltine and primarily galls vegetative buds. We performed a glasshouse trial exposing A. auriculiformis saplings to one generation of the gall wasp to determine the effect of galling on plant performance. We monitored the growth parameters and development of exposed and unexposed saplings every three weeks for twelve weeks. Above-ground and below-ground biomass were measured at the completion of the trial. One generation of galling reduced sapling height by 37.44 % (±5.57), above-ground biomass by 32.19 % (±4.00), and below-ground biomass by 38.26 % (±7.47). Galling also significantly reduced the other key growth parameters of stem weight, leaf weight, total branch length, and the number of nodes, shoot tips, and leaves. This Trichilogaster species significantly damages juvenile A. auriculiformis plants and could be an effective classical biological control agent if released in Florida, especially if it is not limited by a specialist third trophic level.

[Display omitted] • Significant growth impacts observed after only one generation of wasp galling. • Galling reduced sapling height and above and below ground biomass by more than 30%. • Number of galls negatively correlated with all plant growth parameters. • Trichilogaster sp. is a promising biological control agent for A. auriculiformis. Pre-release efficacy assessments (PREAs) are used in weed biological control to predict the potential impact of prospective agents. These assessments enable the most damaging agents to be prioritised for host testing and release. Further, the inclusion of this information in release applications enables regulators to consider the benefits of an agent alongside any risks. We conducted a PREA to evaluate the efficacy of Trichilogaster sp., a galling wasp that is being considered for release in Florida to control invasive earleaf acacia, Acacia auriculiformis. This species is multivoltine and primarily galls vegetative buds. We performed a glasshouse trial exposing A. auriculiformis saplings to one generation of the gall wasp to determine the effect of galling on plant performance. We monitored the growth parameters and development of exposed and unexposed saplings every three weeks for twelve weeks. Above-ground and below-ground biomass were measured at the completion of the trial. One generation of galling reduced sapling height by 37.44 % (±5.57), above-ground biomass by 32.19 % (±4.00), and below-ground biomass by 38.26 % (±7.47). Galling also significantly reduced the other key growth parameters of stem weight, leaf weight, total branch length, and the number of nodes, shoot tips, and leaves. This Trichilogaster species significantly damages juvenile A. auriculiformis plants and could be an effective classical biological control agent if released in Florida, especially if it is not limited by a specialist third trophic level. [ABSTRACT FROM AUTHOR]

Earleaf acacia (Acacia auriculiformis A.Cunn. ex Benth) is a fast-growing, evergreen tree from Australia that was introduced into the United States as an ornamental plant, but it has become a serious plant invader in Florida, USA. Spread of this invasive tree has accelerated in recent years and current control efforts do not meet conservation or land management needs. Our objective was to review and summarize available information to determine if pursuing classical biological control for earleaf acacia is warranted. Feasibility studies such as this identify pitfalls and conflicts before a project begins, increasing the likelihood that biological control efforts will be successful. This review compiles a list of non-target species based on their geographic overlap with the weed invasion and their relatedness to A. auriculiformis. Feasibility is also determined based on other criteria including conflicts of interest and availability of potential biological control agents. We also present a report from our initial explorations for natural enemies in the native range of Australia. Eighty-nine arthropod and one pathogen species have been identified feeding on earleaf acacia in the native range. Several of the arthropods found have the potential to be host specific and impactful. Few potential conflicts of interests were identified. These findings paired with the high-risk assessment for invasion and lack of sustainable and effective control methods, supports our conclusion that earleaf acacia is a promising target for classical biological control. [ABSTRACT FROM AUTHOR]