Biological controls under the microscope

Friday November 09, 2018 Written by Published in Environment

Discussions and field trips involving the biological control of economically and environmentally important weeds in the Cook Islands, were held at the Ministry of Agriculture on Wednesday and Thursday.

Science biodiversity and conservation team leader Lynley Hayes and entomologist Quentin Paynter from Landcare Research New Zealand, and Michael Dave, a weed biological control scientist from Australia, attended the workshop.

Hayes said the project involved developing biological control for six problem weeds identified by local experts in consultation with scientists.

The top six invasive weeds on the island are mile-a-minute (pokutekute), balloon vine, red passion fruit vine (pou’ue), cockleburr, strawberry guava (tua’va papa’a) and the African tulip (patiti vai).

In the last four years Landcare and the Agriculture ministry had released biocontrol agents to fight all of the six weeds, said Hayes.

The biocontrol agents are a gall-forming scale insect to control the spread of the strawberry guava weed (tectococcus ovatus), heliconius butterflies to combat the red passion fruit vine, the rust fungus (puccinia xanthii) a bio-agent for cockleburr and the balloon vine and the mikania rust fungus (Puccinia spegazzinii) to combat mile-a-minute.

Monitoring of the released agents will be ongoing.

Sometimes weeds can have beneficial properties, says Hayes, and now that controls have been introduced, the weeds will be less invasive.

The weed biocontrol project has operated for five years and is funded by the New Zealand Ministry of Foreign Affairs and Trade.

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