Modern technologies to assess environmental risk of introduced weed biocontrol agents

Exploring metabolite relatedness of species using metabolomics approaches, as an additional and feasible tool to further strengthen biocontrol agents release applications. 

Current host range testing for introduced biocontrol agents (BCAs) in NZ is based on phylogenetic relatedness of the test species.We hypothesize that apparent anomalies in the realised host range of BCAs can be accounted for with metabolic profiles of host plants, a better representation of the phenotype i.e., genotype × environment (G × E) interactions.

We recently showed that the metabolic profile of host plants is significantly modified between the native and introduced environments (Barrett et al., 2024), which could have implications on BCA behaviour and establishment. Therefore, metabolite profiling may throw new light on host plant selection, not obtainable from the centrifugal phylogenetic approach alone, thereby minimising misinterpretations and false positives deduced from traditional approaches.

We will test this using two case studies:

• Cassida rubiginosa released against Cirsium arvense, Californian thistle, and
• Blaptea elguetai, a candidate agent (in containment) for the target weed Tropaeolum speciosum, the Chilean flame creeper.

The anticipated biosecurity outcome is minimised environmental risk by BCAs, achieved by a more definitive host range. By exercising such precise and sustainable management practices aimed at mitigating unintended damage to non-target species, including native plants, we will adhere to Māori taiao (natural world) and kaitiakitanga (guardianship and conservation) principles to devise and implement our research plan. 

Contact Project Leader Arvind Subbaraj: [email protected]