News
NARI contributes to East Timor development
14th March 2005
by Seniorl Anzu
East Timor had approached PNG’s National Agricultural Research Institute (NARI) for a biological control agent to manage the chromolaena weed (Chromolaena odorata) which is spreading and threatening the country’s agriculture and natural vegetation.
Picture of Arctiid larva feeding on chromolaena leaf and a typical gall or swelling caused by gall-fly, stunting the weed's growth
According to NARI Director General Dr Raghunath Ghodake, East Timor’s Ministry of Agriculture, Forestry and Fisheries (MAFF) visited NARI’s Lae based weed management programme in mid March to collect gall flies (Cecidochares connexa) for controlling the notorious and invasive weed of the tropics.
This foreign weed, which has recently become an agricultural and environmental concern in PNG, has also been a threat to East Timor. Outside its native range in tropical America, chromolaena is a serious invader of pastures, young tree plantations, fallow lands, old shifting agricultural areas, conservation areas and other areas close to human settlement. Chromolaena is a plant of open land in the tropics where it supersedes pioneer ephemeral herbs and causes problems ranging form habitat displacement for native flora and fauna to direct competition for nutrients, water and light with perennial crops.
NARI assisted MAFF in supplying the exotic biological control agent, which is proving to be a success in controlling the weed in established sites. Well over 1000 gall flies were collected at Erap in the Markham valley of Morobe province - a site with gall fly establishment - for the visiting team.
This biocontrol agent is spreading and appears to provide good control in many released sites of confirmed provinces since it was introduced in PNG four years ago.
Adults of this agent lay eggs in soft apical stem tissue and the larvae, upon hatching, feeds in the stem causing gall formation. The galls affect (stop) the flow of water and nutrients from the soil to other parts of the plant. Gall formation stunts plant growth and reduces flower formation, which disrupts spread of seeds to uninfected or new areas. A heavy attack can kill the whole plant.
MAFF’s Director of Research and Extension Centre Mr Lourenco Fontes said chromolaena is widely present in East Timor. “Over 80 percent of the total area is covered with chromolaena. The weed has established since the 1970s and is becoming an agricultural threat to the infant nation,” Mr Fontes said. He said the visit was the first approach undertaken to control the weed, adding that the gall flies will be released to four major infested sites in the country.
The NARI weed management programme also supplied the visiting team with Caligrapha pentrina – a biocontrol agent for another weed commonly known as broom stick (Sida).
Discussions during the visit also explored potential research collaboration between NARI and MAFF.
The three-member team included Mrs Tania Paul of Charles Darwin University in Australia, who is the leader of weed management programme in East Timor.
Weed research in PNG and East Timor is supported by the Australian Centre for International Agricultural Research (ACIAR).