Efficacy of naphthoquinones as insecticides against the house fly, Musca domestica L.

Abstract

Acute toxicity of seven naphthoquinones was tested against adults of the house fly (Musca domestica), of which plumbagin was the only one to show sufficient acute toxicity (LD50=21 and 18μg for females and males, respectively). The efficacy of sublethal doses (LD30) was determined for plumbagin. Sublethal doses of plumbagin caused significant reductions in the longevity, fecundity and fertility of M. domestica. The treated females oviposited 22.1–30.5 eggs/female on average, while in the variant where treated males coupled with untreated females, the mean number of eggs was 129.3 eggs/female, thus significantly less compared to the control of 224.8 eggs/female. A significantly lower hatching capacity of the larvae (50%) was found in eggs oviposited by treated females compared to the control, where 99% of the larvae hatched.The larvae that did hatch showed reduced vitality compared to the control larvae, manifested by higher mortality during their development and significantly lower natality, which ranged between 44.1 and 57.3% in all treated variants, whereas the natality of the control larvae achieved 76%. Of the tested naphthoquinones, plumbagin exhibits a potential for the development of new botanical insecticides against the house fly.