Biocontrol introduction

Target pest: Hypericum androsaemum (Malpighiales: Hypericaceae), tutsan

Agent introduced: Melampsora hypericorum (Pucciniales: Melampsoraceae), tutsan rust

Imported:

Landcare Research (2019d) - present in New Zealand since the 1950s.

Release details:

Landcare Research (2019d) - self-introduced.

Establishment:

Landcrare Research (2019) - there are two main strains of the rust present in New Zealand, with one type in the South Island and the other in the North Island. Stewart Island has both.

Impacts on target:

Landcare Research (2019) - tutsan rust appears to be controlling tutsan in the South Island, where the plant is not invasive, but not in the North Island. There are four genotypes of tutsan present in New Zealand, although two of these are rare. The two common genotypes, like the two rust genotypes, are mainly divided between the North and South Islands. Testing in Europe has shown the North Island tutsan genotype to be resistant to all of the four strains of the rust found in Europe (which includes the two found in New Zealand). This helps to explain why tutsan is problematic in the North Island but not in the South Island.

References

Landcare Research (2019d). Final phase for tutsan project. Weed Biocontrol: What's New? 88, May 2019. https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/weed-biocontrol-issue-88/final-phase-for-tutsan-project