Plant traits that predict the success of weed biocontrol.

We constantly seek generalisations to help us predict which weeds will make better targets for biocontrol, so that we can get a better bang for our buck.

Analysing data from 80 weed biocontrol programs from around the world revealed three plant traits are good at predicting the impact of novel (pioneering) weed biocontrol programmes. Those traits are: whether a weed was reported to be a major weed in its native range; the mode of reproduction (sexual or asexual), and habitat/ecosystem type (aquatic or wetland versus terrestrial). Biocontrol impacts are generally high against weeds with the best combination of traits (not weedy in the native range, asexual, aquatic plant species) and generally (but not always) low against weeds with the worst combination of traits.

Moreover, countries that conduct weed biocontrol programmes freely share weed biocontrol agents and the success of pioneering programmes predicts how well a repeat programme should perform against the same target weed in other regions. In other words, repeat programmes in New Zealand using biocontrol agents already proven to work in other countries, are predicted to have a high probability of success, but biocontrol agents that failed to control a weed in another country, probably won’t succeed in New Zealand either.

Although weed species that are predicted to be easier targets will gain support from this model, weed species that are predicted to be more difficult targets with the worst combination of traits may still be prioritised as suitable targets for biocontrol if they are sufficiently important so that the increased risk of failure is offset by the greater potential benefits of successful control. The predictive framework means that the higher risk of the programme will be known at the outset, so that it is resourced accordingly and realistic expectations are well-managed from the outset.

Plant traits that predict the success of weed biocontrol.

In this section

Further reading