An expert on biological control says Samoa has over 300 invasive weeds and allowing them to grow will have an impact on forestry, crops and the safety and livelihoods of Samoans.

Dr. Lynley Hayes of Manaaki Whenua Landcare in New Zealand, who travelled to Samoa to attend a national workshop on weed prioritisation at Tanoa Hotel on Wednesday, told the Samoa Observer that there are over 300 invasive weeds in the country.

She said while all invasive weeds should be eradicated, authorities in Samoa should be “pragmatic” and just choose a few to start with in order to minimise their impact on forestry, crops, livelihoods and the safety of citizens.

"There are over 300 invasive weeds in Samoa but we have to be pragmatic and choose a few to start the process of eradication with,” Dr. Hayes said in an interview.

“Today we identified as a group, a top five list, and from there we decided on two biocontrol agents that have already succeeded in American Samoa and Fiji.”

According to Dr. Hayes, invasive weeds are detrimental to forestry, crops as well as other aspects of the Samoans’ livelihoods and even safety, due to the increasing impact of climate change in the islands. 

She said the practice of eradicating invasive weeds is not new to Samoa and has been done before. 

"The eradication of invasive weeds is not new to Samoa but it has been a while since it was done. 

“The last time we worked with invasive weeds in Samoa was 1988 and it was a success story.”

As part of biological control other living organisms are often used to suppress or render obsolete pest populations, hence the introduction of an insect, which Dr. Hayes should be credited for the success in eradicating the vaofefe palagi, mimosa invisa or giant sensitive plant in Samoa. 

"We came in 1988 to look for the mimosa invisa, and it was very hard to find because the bio control agent that was introduced was doing its job," she said.

The success of the invasive weeds eradication will also depend on the processes stipulated by the Government, according to Dr. Hayes. 

But for now she said she is bringing home the message that work needs to be done on invasive weeds, due to the rising impact of climate change on the islands, which are only exacerbated by invasive weeds. 

The national workshop on Wednesday was held by the Ministry of Natural Resources and Environment in partnership with the Management of Invasive Species for Climate Change Adaptation in the Pacific (MISCCAP) project and the Secretariat of the Pacific Regional Environment Programme (S.P.R.E.P) and the Pacific Regional Invasive Species Management Support Service (PRISMSS).

The workshop was held under the auspices of the Natural Enemies Natural Solution (N.E.N.S) component of the MISCCAP project, identifying priority weeds in Samoa and revisiting the findings of work already been done in the past, in order to draw up a list of natural enemies (biological agents) that are available and for which weeds. N.E.N.S. main focus is to restore the natural balance between weeds and the environment through natural enemy intervention. 

In many situations N.E.N.S. is the best, least damaging, cost-effective and sustainable method for controlling weeds when compared to other control methods such as the use of chemical control (herbicides) – it is also more realistic when compared to manual control methods.

The M.N.R.E. Chief Executive Officer, Lealaisalanoa Frances Brown-Reupena opened the national conference where there were presentations by the Ministry of Agriculture and Fisheries, the M.N.R.E. and Dr. Hayes who is also the N.E.N.S. specialist advisor. 

An in-depth discussion towards condensing the long list of invasive weed species into a list of at least 20 priority weed species ensued.

“Samoa is happy to be part of the NENS-MISCCAP project,” said Lealaisalanoa in her keynote address.

“N.E.N.S is the practice of introducing natural enemies into a site to manage invasive weeds when eradication is deemed non-feasible. 

“When introduced, the selected natural enemies begin to feed on the target weed in order to keep its population low thus controlling its population and containing its spread.”

William Young, a PhD Student at the University of Newcastle currently attached to the S.P.R.E.P. Headquarters, told the Samoa Observer that part of his research is to connect with communities on their reactions and perspectives of invasive weeds.

"I have had several conversations with different groups of people in Samoa on the subject,” he told this newspaper. 

“It is very interesting to learn from our communities what they think and know of invasive weeds. 

“There are some invasive weeds which groups use for dance decorations and others use for medicine.

"We will be going to Apolima this weekend to have a dialogue, if allowed by the 60 or so residents there about how they deal with invasive weeds.

"I think communicating with the communities helps because we need to get to an understanding of what our people know about the invasive weeds or do not know and what we can learn from them to better the methods of dealing with invasive weeds.”