Insecticidal Activity of Kaffir Lime (Citrus hystrix) against Rice Weevil (Sitophylus oryzae)

The aim of this study is to analyze the potential use of kaffir lime leaves and peel extract as bioinsecticides against rice weevils. The assessment of bioinsecticidal activity was studied through contact activity, repellency, antifeedant, and progeny and growth development tests. Contact activity tests resulted in increased adult mortality with increased extract concentrations from 10 to 50 mg/L after 24 hours. The leaf extract (LC50=18 mg/L) showed a higher mortality rate compared to fruit peel extracts (LC50=54 mg/L), with 100 % and 60 % mortality, respectively. The leaf extracts with a mean repellency of 68 % significantly repelled rice weevils compared to the 42 % repellency of fruit peel extracts. The leaf extract was classified in repellency class IV, while the peel extract was in repellency class II. With the use of Kaffir lime leaf extracts, F1 adults were completely suppressed at 20 mg/L concentration of leaf extract with a 100 % inhibition rate.