Prioritizing invasive plants for biological control in in western USA
In the United States of America, between 1902 and 2020, 83 weed species have been the target of biological control programmes. With an increased number of potential targets, and an overall trend in decreasing funds, prioritising targets for biological control is important. The Biological Control Target Selection (BCTS) system was developed by researchers in South Africa to address this issue and it was subsequently adapted for the USA and applied to 295 western state-regulated invasive plant species. The USA BCTS system contains three sections (1) the impact of the target species, (2) the likelihood of achieving control and (3) the investment required. The responses to individual questions within each section are scored and an overall score, the BCTS index is calculated as: (∑ Section 1) x [(∑ Section 2) + (∑ Section 3)], where the higher the score the higher priority. The outcome of the analysis identified 20 high priority invasive plant species for biological control in the Western USA (Table 1).
Table 1. Top twenty species prioritised for biological control in the Western USA
Species | Family | BCTS score | Origin | EPPO Status |
Alhagi maurorum | Fabaceae | 3024 | Asia/Europe | |
Araujia sericifera | Apocynaceae | 3010 | S. America | L IAP |
Tamarix aphylla | Tamaricaceae | 2997 | Africa/Asia | |
Rubus fruticosus | Rosaceae | 2960 | Europe | |
Buddleia davidii | Scrophulariaceae | 2937 | Asia | L IAP |
Clematis vitalba | Ranunculaceae | 2835 | Africa/Asia/Europe | |
Bryonia alba | Cucurbitaceae | 2800 | Asia/Europe | |
Spartina anglica | Poaceae | 2775 | Europe | |
Bothriochloa ischaemum | Poaceae | 2769 | Africa/Asia/Europe | |
Iris pseudacorus | Iridaceae | 2720 | Africa/Asia/Europe | |
Myriophyllum spicatum | Haloragaceae | 2720 | Africa/Asia/Europe | |
Nardus stricta | Poaceae | 2720 | Widespread | |
Rorippa austriaca | Brassicaceae | 2720 | Asia/Europe | |
Cabomba caroliniana | Cabombaceae | 2688 | Americas | L IAP |
Spartium junceum | Fabaceae | 2686 | Europe | |
Zygophyllum fabago | Zygophyllaceae | 2686 | Asia | |
Sphaerophysa salsula | Fabaceae | 2628 | Asia | |
Koenigia polystachya | Polygonaceae | 2627 | Asia | L IAP |
Daphne laureola | Thymelaeaceae | 2590 | Africa/Europe | |
Ranunculus acris | Ranunculaceae | 2590 | Asia/Europe |
L IAP: EPPO List of Invasive Alien Plants
Sources
Winston RL, Schwarzländer M, Hinz HL, Rushton J, Pratt PD (2024) Prioritizing weeds for biological control development in the western USA: Results from the adaptation of the biological control target selection system. Biological Control 198, 105634. https://doi.org/10.1016/j.biocontrol.2024.105634