Background Myiasis caused by Lucilia sericata (Diptera: Calliphoridae) is widely distributed throughout the world and affects both humans and animals. In addition, L. sericata larvae and adults may play a role in spreading causal agents of mycobacterial infections. Therefore, it is important to establish new and safe alternative methods of controlling this blowfly.
Methods The insecticidal effectiveness of four commercially available essential oils [lettuce (Lactuca sativa), chamomile (Matricaria chamomilla), anise (Pimpinella anisum), rosemary (Rosmarinus officinalis)] against third larval instars of L. sericata was evaluated. The effects of sub-lethal concentrations of these oils on pupation rates, adult emergences, sex ratios, and morphological anomalies were also determined.
Results The oils were highly toxic to L. sericata larvae, with median lethal concentrations
(LC50) of 0.57%, 0.85%, 2.74%, and 6.77% for lettuce, chamomile, anise, and rosemary
oils, respectively. Pupation rates were markedly decreased after treatment with 8% lettuce
oil, and adult emergence was suppressed by 2% lettuce and chamomile oils. Morphological
abnormalities were recorded after treatment with all tested oils, and lettuce was the major
cause of deformation. There was a predominance of males over females (4 : 1) after
treatment with lower concentrations of chamomile and rosemary; such a skew toward
males would lead to a population decline. Conclusions The four tested oils are inexpensive and may represent new botanical insecticides for controlling blowflies.