Control of Sclerotium rolfsii in peanut by using Cymbopogon martinii essential oil

Abstract

Essential oils of seven species were investigated in order to control peanut plants against white mold (Sclerotium rolfsii Sacc.). The assays were carried out by in vitro and in vivo assays. At first, fungitoxicity and suppression of oxalic acid diffusion (SOAD) bioassays were performed in order to evaluate the mycelial growth of fungus. Then, validation assays were carried out in greenhouse, involving inoculation of fungus in the seeds and further plant treatments with essential oil. Four isolates of S. rolfsii were tested in different oil concentrations. Cymbopogon martinii oil at 300 ppm inhibited the mycelia growth of S. rolfsii in 55% and also the number of sclerotia. In validation assay, we found that a single dose of C. martinii oil at 400 ppm reduced the rate of disease in 55%, confirming the in vitro assays. The follows traits: number of pods/plant, pod weight and harvest index increased in 57, 54, and 40%, respectively, in all C. martini oil treatments. These results demonstrate that C. martinii oil at low concentration may serve for new formulations in the treatment and prevention of white mold.

Isolation and Morphological Characterization of Sclerotium rolfsii-Inciting Stem rot Disease in Groundnut (Arachis hypogaea L .)

“…3). The comparable findings also reported by Yrlânia et al (2015) proved the virulence of S. rolfsii on groundnut plants. The first symptoms were tested 48 h after inoculation, which evolved to stem bottleneck and plant wilting with the presence of white mycelium under greenhouse conditions.…”

Microencapsulation of Lippia turbinata essential oil and its impact on peanut seed quality preservation

“…According to the data at present available the inhibition of peanut germination due to use of EOs had not been reported. De Lira Guerra et al (2015) observed no inhibition of germination in peanut seeds treated with seven EOs (Lemongrass martinii (Roxb.) Stapf var.…”

Microencapsulation of Peumus boldus essential oil and its impact on peanut seed quality preservation

“…This undesirable effect was previously registered in microcosm assays when the formulation was applied directly on shelled peanut seeds (Girardi et al, 2016). Therefore, the change in the application methodology employed in this work, which consisted in spreading the microcapsules on in-pod peanut, it was not sufficient to avoid the adverse effect on GDe Lira Guerra et al (2015) evaluated the allelopathic effect of seven EOs (Cymbopogon martinii, Cedrus atlantica, Copaifera officinalis, Zingiber officinale, Eucalipto staigeriana, Juniperus communis and Ocimum basilicum) at the dose of 1000 ppm on peanut seeds, without findings inhibitory effects. However, in vitro studies conducted by Verdeguer et al (2011) evidenced the phytotoxic effects of boldo EO on Amaranthus hybridus and Portulaca oleracea, attributing this activity to the high content of oxygenated monoterpenes that it possesses.…”