Toxicity and oviposition deterrence of essential oils of Clinopodium nubigenum and Lavandula angustifolia against the myiasis-inducing blowfly Lucilia sericata

Abstract

Cutaneous myiasis is a severe worldwide medical and veterinary issue. In this trial the essential oil (EO) of the Andean medicinal plant species Clinopodium nubigenum (Kunth) Kuntze was evaluated for its bioactivity against the myiasis-inducing blowfly Lucilia sericata (Meigen) (Diptera Calliphoridae) and compared with that of the well-known medicinal plant species Lavandula angustifolia Mill. The EOs were analysed and tested in laboratory for their oviposition deterrence and toxicity against L . sericata adults. The physiology of EO toxicity was evaluated by enzymatic inhibition tests. The antibacterial and antifungal properties of the EOs were tested as well. At 0.8 μL cm -2 , both EOs completely deterred L . sericata oviposition up to 3 hours. After 24 h, the oviposition deterrence was still 82.7% for L . angustifolia and the 89.5% for C . nubigenum . The two EOs were also toxic to eggs and adults of L . sericata . By contact/fumigation, the EOs, the LC 50 values against the eggs were 0.07 and 0.48 μL cm -2 while, by topical application on the adults, LD 50 values were 0.278 and 0.393 μL per individual for C . nubigenum and L . angustifolia EOs, respectively. Inhibition of acetylcholine esterase of L . sericata by EOs (IC 50 = 67.450 and 79.495 mg L -1 for C . nubigenum and L . angustifolia , respectively) suggested that the neural sites are targets of the EO toxicity. Finally, the observed antibacterial and antifungal properties of C . nubigenum and L . angustifolia EOs suggest that they could also help prevent secondary infections.

Allium sativum, Rosmarinus officinalis, and Salvia officinalis Essential Oils: A Spiced Shield against Blowflies

“…In particular, among the foodborne disease bacteria, we observed a strong activity against E. coli, while S. enterica was the most resistant strain. In line with these results, S. enterica was found to be the most resistant microbial strain for the EOs extracted from C. nubigenum and L. angustifolia [28]. Such antimicrobial activity of the EOs is important since Calliphoridae are vectors of numerous microorganisms and foodborne pathogens [1][2][3].…”

“…The responsiveness of C. vomitoria to the three EOs was confirmed by the results of the oviposition deterrence bioassay that showed that A. sativum, R. officinalis, and S. officinalis EOs are able to exert a clear deterrent activity against C. vomitoria females' oviposition. Such results are in good agreement with previous experiments showing a strong oviposition deterrence by Artemisia dracunculus L. and A. annua L. (Asteraceae) EOs [19] against C. vomitoria and of Lavandula angustifolia Mill., and Clinopodium nubigenum (Kunth) EOs against Lucilia sericata Meigen (Diptera Calliphoridae) [28]. A repellent effect of EOs was also observed by Callander and James [38] who obtained the complete inhibition of oviposition of L. cuprina on wool treated with tea tree (Melaleuca alternifolia Maiden & Betche) EO.…”

“…The antibacterial activity of the EOs was determined by assessing the minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) following the method described by Bedini et al [28]. In brief, 5 mL of 10 7 UFC mL −1 microbial broth was incubated in tubes containing 50 µL of decreasing concentrations of the EO (10, 5, 2.5, 1.25, and 0.63 µL per tube).…”

Behavioral effects induced by organic insecticides can be exploited for a sustainable control of the Orange Spiny Whitefly Aleurocanthus spiniferus

“…Pest control could be achieved through the integration of multiple tactics; among the possible alternatives to synthetic pesticides, the use of chemical stimuli to manipulate insect behavior is considered a suitable biotechnical control tool in the management of several insect pests 29 . Some insecticides, beside lethal toxicity, affect insect behavior preventing settling on the host plant, probing and feeding, oviposition, and virus transmission 33,34 . Therefore, behavioral effects caused by an insecticide that is apparently non-toxic for the insect in conventional tests, could in fact permit to contain the insect populations and associated yield losses.…”

Lamiaceae medicinales y aromáticas comercializadas en el Área Metropolitana de Buenos Aires, Argentina

“…antimicrobiano (Bedini et al, 2019), pediculicida (Limoncu et al, 2017), repelente de insectos (Štefanidesová et al, 2017). A: Condimento para salsas, ensaladas, estofados y dulces, saborizante de bebidas.…”