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.

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the aim of the present research was to identify and analyse the biocontrol capacity of nine local Trichoderma spp. isolates against Lasiodiplodia theobromae. the isolates were identified as T. asperellum (3), T. harzianum (5) and T. koningiospsis (1). these fungi significantly slowed L. theobromae mycelial development in vitro, with maximum reductions of 75.4 and 64.1% reported with T. asperellum BRs-1 and T. harzianum BRs-7, respectively. the antagonistic fungi were able to inhibit the growth of L. theobromae through the production of mycotoxic compounds. after 5 days of incubation, the fungi produced a large number of conidia and targeted lytic enzymes in solid-state fermentation (ssF). the principal component analysis (Pca) clustered Trichoderma strains according to their phylogenetical relationships and demonstrated a tight association between the species sub-group and antagonistic features. these findings suggest that local soil-derived Trichoderma spp. have the potential to be efficient biological agents against L. theobromae.