Distribution, development biology and behavior of <em>Dacus persicus</em> associated with <em>Calotropis gigantea</em> in Sri Lanka

Abstract

Calotropis gigantea (Crown flower, Giant milkweed or Wara) is a native medicinal plant in Sri Lanka. It is recorded as an invasive plant in Australia, Brazil, USA, etc. Dacus persicus is recorded as a highly destructive monophagous pest of C. gigantea in Sri Lanka. Larvae of D. persicus feed on developing fruits and seeds and reduce the reproductive output of the plant significantly making it a suitable candidate for biocontrol. Therefore, the present study was aimed to investigate the distribution and reproductive biology of Dacus persicus to assess the potential as a biocontrol agent for Calotropis species. D. persicus distributed in six provinces in Sri Lanka. The duration of mating and ovipositing of D. persicus was 54 and 92 minutes, respectively. It laid eggs in the seed chamber of developing fruits and the fruit size is highly correlated (p < 0.001, r = 0.990) with the number of laid eggs. Only one egg cluster of D. persicus found within a single fruit having 18.5 (± 0.85) eggs per cluster and the eggs hatched in 3 days. The duration of larval and pupal stages for D. persicus were 24 and 12 days, respectively. These results provide essential information needed in adopting D. persicus as a biocontrol agent of C. gigantea.

Keywords

• calotropis gigantea, dacus persicus, invasive species, biocontrol