Dalo is one of the most important staple food crops in Fiji not only because of its traditional significance but also because of its economic importance. Fiji is currently the major exporter of dalo in the Pacific with exports valued at almost $20 million dollars annually.
However, Fiji’s dalo is also threatened by the taro beetle (Papuana uniondis) Adult dalo beetle damage the underground corms by chewing and burrowing into them creating tunnels. These beetles create large cavities allowing secondary rots to develop causing low quality corms for consumption. Dalo damaged by beetles cannot be exported.
The adult beetle is black, shiny and 15-20mm in length. Many P. uninodis species has a horn on the head with the average life cycle of 22 to 25 weeks. The adult beetles fly from the breeding sites to the taro field and tunnel through the soil and into the base of the taro corm. They then proceed to feed on the growing corm, leaving large holes that degrade the market quality and value of the corm. The wounds created while feeding promotes a path way for rot-causing organisms. The feeding activity can cause wilting and even death of the affected dalo plants.
Areas infested with Taro Beetle
Taro beetle was first found in Fiji in 1984 and since then it is being localized in the Central Division of Viti Levu extending from Tailevu to Sigatoka and up to Vunidawa in the interior. Lovoni in Ovalau, the Ra Province from Nalidi to Navitilevu along the Kings Highway are also taro beetle infested areas. Recent findings of taro beetle have been in Gau. In addition to this, continuous survey will be carried out to ascertain the presence or absence of taro beetle in Bua, Ckaudrove in Vanua Levu.
Numerous efforts have been made to develop effective control measures for the taro beetle. These include:
• Crop rotation, clean planting material (free from soil, grubs and beetles).
• Destroy breeding sites at the sides of dalo gardens.
• The fungus- Metarhizium- works under experimental conditions, but as yet there is no recommendation for farmers. A virus has been tried without success.
The chemical imidachloprid (Confidor) and cypermerthrin (Mustang) have controlled Papuana beetles in Fiji. Please do seek advice from the Extension and Research Division of the Ministry of Primary Industries (MPI).
Biosecurity Containment, Advice and Control Measures
• Avoid the movement of dalo corms, planting material and other taro beetle host plants from taro beetle infested areas to non infested areas.
• Contact your nearest Biosecurity Office or Agricultural Officer for the necessary supervision of treatments to be carried out for infested dalo planting materials.
Seek assistance or approval from the Biosecurity Authority of Fiji (BAF) if you want to move dalo or dalo planting material and are not sure of the taro beetle infested or non infested areas.