Antibiotic resistance has been called one of the world’s most pressing public health threats. The combination of essential oils with conventional antibiotics is one of the emerging approaches that could help prevent this problem. In light of this, this study aimed to investigate the impact of combination of Ruta montana essential oil with conventional antibiotics on some pathogenic bacteria. The essential oil isolated by steam-hydrodistillation was first analyzed using GC-MS then tested alone and in combination with five recommended antibiotics against three bacterial strains by the agar disc diffusion and broth micro-dilution methods. Out of forty-nine peaks, thirty-eight components were identified representing 98.17% of the total oil composition. The major components were 2-Undecanone (63.39%), 2-Nonanone (5.65%), 2-Acetoxytetradecane (4.94%), 2-Decanone (4.47%) and 2-Dodecanone (3.35%). While R. montana essential oil showed only weak antibacterial activity compared to the antibiotics tested alone, unexpectedly, the combination of RM essential oil with antibiotics remarkably increased the antibacterial activity of the antibiotics through synergistic effects in up to 70% of cases. These results suggest that combining antibiotics with essential oils, even those with low antibacterial activity, may be effective in overcoming problems caused by increasing bacterial resistance.

The aphid Aphis pomi represents an important pest of apples. The use of botanical extracts may be a safe and effective way to control this pest. In this context, we studied the aphicidal and repellent effects of aqueous extracts of Salvia microphylla against A. pomi. Five concentrations were tested on two main aphid parameters: mortality rate and percentage of repellency. The results showed that concentrations of 10% recorded the highest mortality rate (73.33%) and percentage of repellency (62.59%). After further field investigations, the use of S. microphylla may constitute a component of the integrated management of aphids.

The research of new control methods that have low negative effects represent analternative aiming to limit disadvantages of chemical control of pests. This studyaimed to test the effect of 11 aqueous plant extracts belonging to four species(Santolina africana, Juniperus thurifera, Artemisia herba-alba and Pituranthosscoparius), on the larvae of the aphid Aphis craccivora installed on the leaves ofRobinia pseudoacacia under laboratory conditions. The insecticidal effect ofaqueous extracts on the mortality of aphids was evaluated by the introduction ofacacia leaflet into an extract and infestation of them by 10 larvae of the aphid.Later, a counting of dead larvae after 3, 6, 12 and 24 h was performed. In addition,we investigated the effect of the aqueous extracts on the orientation of the aphidsby putting the latter in a position of choice between six leaflets, each treated with adifferent extract. In addition, a phytochemical screening was carried out to detectthe presence of saponins and polyphenols in the extracts studied. Through ourstudy, the extract obtained from S. africana at a concentration of 15% was the mosteffective with a mortality rate higher than 80% after 24 h of artificial infestation.As for the effect of the four extracts on the orientation of the cowpea aphid, theydid not attract the larvae massively. Regarding phytochemical screening,differences in the chemical composition of the analyzed extracts were observed.These differences may explain in part the variation of aphicidal effects of testedplant extracts.