Author
Makereta Ranadi
makeretaciri87@gmail.com
Ministry of Agriculture and Waterways, Fiji.
Sigatoka
Abstract
Sida acuta, a malvaceous weed native to Central America, has become a serious invasive species in Fiji, affecting both crop and livestock productivity. In 1997, Calligrapha pantherina, a leaf-feeding beetle, was introduced from Papua New Guinea to suppress S. acuta. Field surveys across Viti Levu, Taveuni, Kadavu, Gau, Koro, Beqa, Ovalau, and parts of Vanua Levu confirmed beetle dispersal up to 5 km from release sites and demonstrated significant reduction in weed populations. To support mass rearing, laboratory studies were conducted under controlled conditions (24–28°C, 65–70% RH) during 2017–2018. It helps to identify critical points for intervention and improving overall yield during mass production. Developmental durations for egg, larval, and pupal stages ranged from 2–7, 11–20, and 3–11 days, with survival rates of 81%, 46%, and 72%, respectively. This allows laboratory technicians to predict and manage rearing timelines efficiently. The sex ratio of newly emerged adults was 5:4 (male: female), with females exhibiting longer lifespans. These findings support the continued use and expansion of C. pantherina as an effective biological control agent for S. acuta in Fiji.
keywords
Sida acuta
Calligrapha pantherina
biological control
weed suppression
Fiji
Highlights
C. pantherina successfully established across multiple Fijian islands
Field data show effective suppression of S. acuta populations
Lab studies support mass rearing for strategic releases