Bio-Herbicidal Potential of The Essential Oils from Different <i>Rosmarinus Officinalis</i> L. Chemotypes in Laboratory Assays

• Main Authors: Jihane El Mahdi, Waed Tarraf, Claudia Ruta, Lea Piscitelli, Adel Aly, Giuseppe De Mastro
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Agronomy
• Subjects: sustainable weed management; monoterpenes; Rosmarinus officinalis L.; chemotypes; bio-herbicides; germination
• Online Access: https://www.mdpi.com/2073-4395/10/6/775

The current study aimed to assess the allelopathic effect of <i>Rosmarinus officinalis</i> L. essential oils (EOs) to define the potent effect against weed species, by exploring distinct chemotypes and their main compounds. The EOs from eight accessions were characterized. Their components were identified by gas chromatography, and four chemotypes were defined; C1 (α-pinene), C2 (camphor), C3 (α-pinene/1,8-cineole), and C4 (α-pinene/1,8-cineole/camphor). Four concentrations of the EOs (400, 800, 1200, and 2400 µL/L) and the main compounds of each chemotype were tested in a laboratory assay against <i>Amaranthus retroflexus</i> L. and <i>Lolium perenne </i>L.<i> </i>in pre- and post-germination. The results showed that the EOs significantly affected all the tested parameters (germination, early growth, and physiological and histological parameters of the weeds under study) in a dose, chemotype, and species dependent manner. <i>A. retroflexus</i> was more sensitive than <i>L. perenne </i>at germination level being significantly inhibited at the lowest dose of all the chemotypes. The latter all exhibited significant effects but with a higher potency of C2 (camphor chemotype) and C3 (-pinene/1,8-cineole chemotype), as well qualitative differences in the induced damage. Our results thus increase knowledge about the role of the monoterpene composition in bio-herbicidal effect, which can help in the development of EO based bio-herbicides.