South America: allies in biocontrol
Fruit fly Toxotrypana australis a potential biocontrol agent for Moth Plant.
In recent years South America has become an important ally in New Zealand’s efforts to control pest plants. Biocontrol is the use of insects or diseases to control these plants and researcher Hugh Gourlay says Landcare Research’s significant involvement in South America marks a monumental shift.
‘Twenty years ago all the weeds we were working on came from Europe and the United Kingdom – gorse, broom, ragwort, thistle species and old man’s beard – but in the last 5 years most of the weeds we’re working on are South American in origin and hence our interest in that continent to look for possible biocontrol agents.
‘What this means of course is that at some point in New Zealand’s recent history South American plants became very popular for people to import, sell and grow in gardens. Now, as with so many other plant species, we’re seeing them evolve into weeds.’
Mr Gourlay and his colleagues spend several weeks every year in South America talking with experts and searching the areas where the plants originated from for insects and diseases attacking the plants that might be good biocontrol agents for New Zealand.
‘It’s important that we search these areas overseas where the weeds originate from, as that is where it is most likely that we will be able to find natural enemies that may have potential as biocontrol agents.’
Currently there are projects in three South American countries (Colombia, Brazil and Argentina) and other projects are likely soon. We also have had close links with Chilean researchers seeking biocontrols for hieracium, gorse and barberry.
Colombia – Seeking biocontrols for banana passionfruit. Unfortunately, the most recent batch of insects perished following the September 4 earthquake in Canterbury.
Brazil – Currently working on three species of beetles for the control of tradescantia (wandering Willie). One beetle is being mass-reared for released and an application to release the other two is currently with ERMA.
Argentina – Collecting insects for testing against moth plant, which is a significant problem, in parts of the North Island. Researchers are also looking at possible biocontrols for Chilean needle grass and will soon investigate possible biocontrols for pampas.
Getting insects out of South American countries has become quite difficult because of these countries’ strict adherence to an international convention on the protection of endemic genetic material. This is one reason why Landcare Research is continually needing to develop formal partnerships with South American researchers and research organisations.