Is biological control of weeds conservation’s blind spot?

Authors: CABRERA WALSH, GUILLERMO - Fuedei; SOSA, ALEJANDRO - Fuedei; MC KAY, FERNANDO - Fuedei; MAESTRO, MARIANO - Fuedei; HILL, MARTIN - Rhodes University; HINZ, HARIET - Commonwealth Agricultural Bureau International (CABI) - Switzerland; PAYNTER, QUENTIN - Landcare Research; Pratt, Paul; RAGHU, S. - Commonwealth Scientific And Industrial Research Organisation (CSIRO); SHAW, RICHARD - Commonwealth Agricultural Bureau International (CABI); Tipping, Philip; WINSTON, RACHEL - Mia Consulting, Llc

Submitted to: Quarterly Review of Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2023
Publication Date: 2/15/2023
Citation: Cabrera Walsh, G., Sosa, A.J., Mc Kay, F., Maestro, M., Hill, M., Hinz, H., Paynter, Q., Pratt, P.D., Raghu, S., Shaw, R., Tipping, P.W., Winston, R.L. 2023. Is biological control of weeds conservation’s blind spot? Quarterly Review of Biology. 98(1):1-28.

Interpretive Summary: Invasive alien species are considered the second most important threat to biodiversity, and among them invasive plants rank the highest. Classical weed biocontrol (CWB) is a technique for controlling widespread exotic plants by re-uniting them with specific natural enemies (arthropods and pathogens) from their native range. This review analyses the support or disapproval of scientists from the fields of ecology, agriculture, and invasive species management towards CWB. The number of weed biocontrol agent releases per region since 1900, was also reviewed, as was their origin. The two were compared to evaluate the levels of approval of CWB amongst the management and policy-makers’ communities. CWB was first used toward the end of the 19th century, but picked up momentum as from the 1950s, with a peak in biocontrol agent releases between 1990 and 1999. A decline occurred in the number of agent releases after that, probably related to lower investment levels, shorter financial cycles, difficulties in obtaining collection, export, and release permits, and a lower tolerance for less than categorical specificity test results. Ecological academia appears to be more hostile/skeptical towards weed biocontrol than scientists in applied and experimental biology. Our synthesis suggests that despite resistance in some quarters of the conservation science community in acknowledging the value of CWB, the general scientific perception of the science and practice of CWB has been consistently favorable during the last 28 years, suggesting that exotic weed management and research need to find common grounds for discussion.

Technical Abstract: Invasive alien species are considered the second most important threat to biodiversity, and among them invasive plants rank the highest. Classical weed biocontrol (CWB) is a technique for controlling widespread exotic plants by re-uniting them with specific natural enemies (arthropods and pathogens) from their native range. This review analyses the support or disapproval of scientists from the fields of ecology, agriculture, and invasive species management towards CWB. The number of weed biocontrol agent releases per region since 1900, was also reviewed, as was their origin. The two were compared to evaluate the levels of approval of CWB amongst the management and policy-makers’ communities. CWB was first used toward the end of the 19th century, but picked up momentum as from the 1950s, with a peak in biocontrol agent releases between 1990 and 1999. A decline occurred in the number of agent releases after that, probably related to lower investment levels, shorter financial cycles, difficulties in obtaining collection, export, and release permits, and a lower tolerance for less than categorical specificity test results. Ecological academia appears to be more hostile/skeptical towards weed biocontrol than scientists in applied and experimental biology. Our synthesis suggests that despite resistance in some quarters of the conservation science community in acknowledging the value of CWB, the general scientific perception of the science and practice of CWB has been consistently favorable during the last 28 years, suggesting that exotic weed management and research need to find common grounds for discussion.