Potential of insect growth regulators for the control of Musca domestica (Diptera: Muscidae) with respect to their biochemical and histological effects

Housefly causes a variety of health problems to humans and animals. Therefore, it is crucial to find out effective methods for the control of housefly larvae to avoid health problems associated with the presence this disease vector insect. Efficacy of insect growth regulators (IGRs), chlorfluazuron, lufenuron, methoxyfenozide and pyriproxyfen, against larvae of Musca domestica (Diptera: Muscidae), was assessed. The IGRs were mixed with food media at concentrations of 2.5, 5.0, 10.0, 25.0, 50.0, 75.0 and 100.0 mg/kg (ppm).

The highest larvicidal activity was obtained by chlorfluazuron and pyriproxyfen with LC₅₀ values of 6.79 and 7.10 ppm, respectively, 72 h post-treatment. Also, 25.0 ppm of chlorfluazuron and 75.0 ppm of methoxyfenozide as well as lufenuron were shown to fully suppress adult emergence and survival percentages (0.0%). Moreover, the activity of three digestive enzymes suppressed in the treated larvae with pyriproxyfen and chlorfluazuron: amylase (enzyme ratio (ER) = 0.71 and 0.78), lipase (ER = 0.54 and 0.63) and proteases (ER = 0.62 and 0.66), respectively. Also, methoxyfenozide and pyriproxyfen inhibited acetylcholinesterase (AChE) and general-esterase (GE) activity with ER (0.28 and 0.59) and (0.61 and 0.72), respectively. The histological examination of M. domestica larvae treated with IGRs showed changes in midgut; for example, the epithelial cells were broken, deformed and loss their columnar structure. Also, the peritrophic membrane disappeared completely.

The findings of the current study indicate that the tested IGRs have a potential to be applied in IPM programs of M. domestica.