Evaluation of Clove Essential Oil as a Mycobiocide Against Rhizopus stolonifer and Fusarium solani, Tuber Rot Causing Fungi in Yam (Dioscorea rotundata Poir.)

Abstract

To exploit natural products for plant disease control, the essential oil of Syzygium aromaticum (L.) Merr. & Perr. (clove) was investigated for its antifungal activity against Rhizopus stolonifer and Fusarium solani, the postharvested yam tuber rot pathogens. The essential oil was obtained by hydrodistillation using a Clevenger‐type apparatus. The chemical composition of the oil was determined by gas chromatography and gas chromatography coupled with mass spectrometry. Antifungal activities of the oil were tested in vitro against mycelia growth and spores germination. In situ tests were conducted on healthy yam tubers, and necrosis symptoms were assessed. Results showed that eugenol (79.4%), eugenylacetate (9.2%) and isocaryophyllene (7.0%) were the major components. The oil exerted antifungal activities with total inhibition (TI) of the mycelia growth of R. stolonifer and F. solani was recorded at 200 and 300 ppm, respectively, while TI of spores germination was recorded at 31.25 and 250 ppm, respectively. For the standard fungicide (Ridomil®), TI value of mycelia growth was 1600 ppm for the both pathogens, while TI of spores germination were 200 ppm and 1600 ppm, respectively, for Rhizopus and Fusarium. In situ tests showed complete inhibition of yam tuber rot when the essential oil was applied at 2000 ppm for preventive tests. This oil also reduced significantly (P ≤ 0.05) necrosis development on yam tuber for curative test at the same concentration. Total inhibition of the necrosis by Ridomil (3000 ppm) was observed only for Rhizopus on preventive test. There were positive correlations between the oil concentration and the reduction of necrosis cause by R. stolonifer and F. solani. These findings showed that clove essential oil may serve as environmental friendly bio‐fungicide for the management of postharvest yam tuber rot.

Thymol Encapsulated into HP-β-Cyclodextrin as an Alternative to Synthetic Fungicides to Induce Lemon Resistance against Sour Rot Decay

“…Thus, under curative conditions, 10 h of separation between G. citri-auriantii inoculation and lemon treatments could be enough for the fungus to invade the fruit cells and HP-β-CD-thymol complex would be less able to control the decay spread. Thus, Sameza et al [ 29 ] reported that infection control becomes difficult once a pathogen penetrates plant tissues.…”

Antifungal activity of the essential oils of plectranthus neochilus (Lamiaceae) and tagetes erecta (Asteraceae) cultivated in brazil

“…9 Although the synthetic fungicides are effective, the development of fungal resistance, toxicity to non-target organisms and environmental problems is due to its continuous or repeated application. 10 The search for antifungal compounds from natural sources has increased over the last decade, and plants continue to be a major source of biologically active compounds that may provide lead structures for the development of new drugs. 11 In this scenario, essential oils constitute a rich source of bioactive chemicals and have been recently pointed out as a promising alternative against the pathogenic fungi.…”

Inhibitory Action of Biofungicide Physcion on Initial and Secondary Infection of Magnaporthe oryzae

“…To solve problems above many scientists have increased interests in finding safer substances including plant extracts and plant secondary metabolites with fungicidal activities (Copping and Menn 2000;Yoon et al 2011;Sameza et al 2016).…”

“…Synthetic fungicides have been widely applied as preventive or curative measures to control plant diseases over the past several decades, but the continuously repeated and excessive applications of synthetic fungicides have resulted in fungus resistance (Gisi et al 2002;Steffens et al 1996;Zhang et al 2006), residual toxicity in food (Navarro et al 2011) and disruption of ecosystem (Tu et al 2011). To solve problems above many scientists have increased interests in finding safer substances including plant extracts and plant secondary metabolites with fungicidal activities (Copping and Menn 2000;Yoon et al 2011;Sameza et al 2016).…”