Impact of Mikania micrantha on crop production systems in Viti Levu, Fiji.

Abstract

A study assessing the economic impacts of Mikania micrantha Kunth. ex. H.B.K. (hereafter, mikania) was conducted using a targeted questionnaire survey in the high rainfall eastern and moderate rainfall western regions of Viti Levu. The survey questionnaire was distributed to 320 (with 59% response rate received) and 275 (with 40% response rate received) farmholders in high rainfall eastern and low rainfall western regions of Viti Levu, respectively. Outcomes of the survey revealed that respondents recognised the negative impact of mikania with a large majority (94% in root crop areas and 100% in sugarcane areas) indicating that they control the weed to prevent crop loss while (76% in root crop areas and 97% in sugarcane areas) do so to prevent the spread of mikania to other areas. A high proportion of respondents in root crop (57%) and sugarcane (66%), indicated that herbicides were the most frequently used management tool for mikania. Controlling weeds was also considered by farmholders as a costly activity, with 35% respondents in root crop areas and 29% respondents in sugarcane areas reporting that they spend AUD $31.00 and $21.00 ha-1 on controlling mikania infestations in root crop and sugarcane areas, respectively. Mikania is mostly controlled in production areas leaving non-production areas as reservoirs for reinfestation. Efforts may be best concentrated in managing the weed in both production and non-production areas. In addition, research using an effective biological control agent(s) for mikania in non-production areas would assist in reducing the density and area of infestation of the weed.