Yanina Rossi

Efficacy of Essential Oils from Edible Plants as Insecticides Against the House Fly, Musca Domestica L.

The compositions of 12 essential oils (EOs) obtained by hydrodistillation of edible fruits and herbs were analyzed by gas chromatography/mass spectroscopy (GC/MS). The insecticidal activity of each oil against the house fly Musca domestica was evaluated by placing flies in a glass jar with a screw cap that held a piece of EO-treated cotton yarn. The dose necessary to kill 50% of flies (LC50) in 30 min was determined at 26 ± 1°C. Twelve EOs and 17 individual terpenes were assayed against M. domestica, showing LC50 values ranging from 3.9 to 85.2 and from 3.3 to >100 mg/dm3, respectively. EO from Citrus sinensis was the most potent insecticide (LC50 = 3.9 mg/dm3), followed by EOs from C. aurantium (LC50 = 4.8 mg/dm3) and Eucalyptus cinerea (LC50 = 5.5 mg/dm3). According to GC/MS analysis, limonene (92.47%), linalool (1.43%), and β-myrcene (0.88%) were the principal components of C. sinensis EO. Limonene was also the principal constituent (94.07%) of C. aurantium, while 1,8-cineole (56.86%) was the major constituent of E. cinerea EO. 1,8-Cineole was most active against M. domestica (LC50 = 3.3 mg/dm3), while (4R)(+)-limonene, was moderately active (LC50 = 6.2 mg/dm3). Dimethyl 2,2-dichlorovinyl phosphate (DDVP) selected as a positive control, showed an LC50 of 0.5 mg/dm3. EOs from C. sinensis, C. aurantium, and E. cinerea show promise as natural insecticides against houseflies.

INSECTICIDE PROPERTIES OF THE ESSENTIAL OILS FROM HAPLOPAPPUS FOLIOSUS AND BAHIA AMBROSOIDES AGAINST THE HOUSE FLY, MUSCA DOMESTICA L

The compositions of the essential oils (EO’s) obtained by hydro distillation from fresh leaves of haplopappus foliosus and bahia ambrosoides was analyzed by gas chromatography/mass spectroscopy (GC/MS). The insecticidal activity of each oil against the house fly Musca domestica was evaluated by placing flies in a glass jar with a screw cap that held a piece of EO-treated cotton yarn. The dose necessary to kill 50% of flies (LC 50 ) in 1 h was determined at 26±1°C. The essential oil from haplopappus foliosus was the most potent insecticide (LC 50 = 4.43 mg/dm 3), wile the EO from bahia ambrosoides shows only moderated insecticide activity (LC 50 = 19.27 mg/dm3). According to GC and GC/MS analysis, limonene (28,00%); epi-bicyclosesquiphellandrene (9,84%); bornyl acetate (7,74%); 4-terpineol (6,36%); p-cymene (6,00%); agarospirol (5,53%); α-muurolene (4,34%); δ-cadinene (3,98%) and caryophyllene (3,97%) were the principal components of haplopappus foliosus EO and limonene (28,16%); α-pinene (11,12%); germacrene D (8,81%); sabinene (5,93%); α-thujene (3,48%); γ-curcumene (3,45%) y α-bergamotene (3,36%) were the principal components of bahia ambrosoides EO. The EO from haplopappus foliosus seem promising as a natural insecticide against houseflies and the difference with the activity of the EO of bahia ambrosoides can be ascribed to the content of oxygenated monoterpenoids and sesquiterpenoids.

Fumigant toxicity of Citrus sinensis essential oil on Musca domestica L. adults in the absence and presence of a P450 inhibitor.

Essential oils (EOs) are potential tools for controlling Musca domestica L. In a fumigant assay, M. domestica adults treated with Citrus sinensis EO (LC50=3.9mg/dm(3)), with (4R)(+)-limonene (95.1%) being its main component, died within 15min or less. The terpenes absorbed by the flies and their metabolites, analyzed using SPME fiber, were (4R)(+)-limonene (LC50=6.2mg/dm(3)), α-pinene (LC50=11.5mg/dm(3)), β-pinene (LC50=6.4mg/dm(3)), and two new components, carveol (LC50=1122mg/dm(3)) and carvone (LC50=19mg/dm(3)), in a proportion of 50, 6.2, 12.5, 6.3 and 25%, respectively. Carveol and carvone were formed by oxidation of (4R)(+)-limonene mediated by cytochrome P450, as was suggested by a fumigation assay on flies previously treated with piperonyl butoxide, a P450 inhibitor. In this experiment, an increase in the toxicity of the EO and (4R)(+)-limonene was observed, as well as a lower production of carveol and carvone.

Molecular response of Musca domestica L. to Mintostachys verticillata essential oil, (4R)(+)-pulegone and menthone

Intense applications of synthetic insecticides for the control of adult Musca domestica have led to the insects developing resistance to most of them. In consequence, there is interest in new active ingredients as alternatives to conventional insecticides. Essential oils (EO) are potential tools for controlling M. domestica because of their effectiveness and their minimal environmental effects. In a fumigant assay, M. domestica adults treated with Minthostachys verticillata EO [LC(50)=0.5 mg/dm(3); majority components by SPME-GC: (4R)(+)-pulegone (67.5%), menthone (22.3%) and (4R)(+)-limonene (3.8%)], died within 15 min or less. The terpenes absorbed by the flies and their metabolites, analyzed using SPME fiber, were (4R)(+)-limonene (LC(50)=6.2 mg/dm(3)), menthone (LC(50)=1.9 mg/dm(3)), (4R)(+)-pulegone (LC(50)=1.7 mg/dm(3)) and a new component, menthofuran (LC(50)=0.3 mg/dm(3)), in a relative proportion of 12.4, 6.5, 35.9 and 44.2% respectively. Menthofuran was formed by oxidation of either (4R)(+)-pulegone or menthone mediated by cytochrome P450, as demonstrated by a fumigation assay on flies previously treated with piperonyl butoxide, a P450 inhibitor, which showed a decrease in toxicity of the EO, (4R)(+)-pulegone and of menthone, supporting the participation of the P450 oxidizing system in the formation of menthofuran. The enzymatic reaction of isolated fly microsomes with the EO or the (4R)(+)-pulegone produced menthofuran in both cases. Contrary to expectations, the insect detoxification system contributed to enhance the toxicity of the M. verticillata EO. Consequently, resistant strains overexpressing P450 genes will be more susceptible to either M. verticillata EO or (4R)(+)-pulegone and menthone.