Antifungal activity of Moroccan medicinal plants against citrus sour rot agent Geotrichum candidum

Aims: The aim of this work was to find an alternative to the chemical fungicides currently used in the control of Geotrichum candidum, the causal agent of citrus sour rot. Methods and Results: Minimal inhibition concentrations (MIC) and minimal fungicidal concentrations (MFC) were determined using agar dilution method. The methanol extracts of Cistus villosus, Ceratonia siliqua and Halimium umbellatum exhibited strong antifungal activity with MIC values ranged between 0·156 and 1·25 mg ml^?1, and MFC values ranged between 2·5 and 5 mg ml^?1. Incidence of sour rot was lowered to 0·00, 3·33 and 11·66% when mandarin fruit was treated with C. villosus, C. siliqua and H. umbellatum methanol extracts at 50 mg ml^?1, respectively, compared with 95% in the control. Conclusions: Cistus villosus, C. siliqua and H. umbellatum methanol extracts successfully reduced the disease incidence caused by G. candidum, and no phytotoxic effects were recorded on citrus fruit. Significance and Impact of the Study: These findings suggest that C. villosus, C. siliqua and H. umbellatum plants may be useful and effective agents for control of citrus sour rot. Such natural products therefore represent a sustainable alternative to the use of synthetic fungicides.     

Biocontrol of root-rot disease of Coleus forskohlii and Coleus amboinicus by using plant extracts as antifungal agents

Different plant extracts were screened for their potential antifungal activity against Fusarium chlamydosporum causing root rot of Coleus amboinicus and Coleus forskohlii; the aqueous and 50% ethanol extract of Annona squamosa, Azadircta indica, Eucalyptus Spp., Ocimum sanctum, Lawsonia inermis, Allium schoenoprasum, Cinnamomum verum Zingiber officinale, Piper nigrum, Calendula officinalis species were found to be effective. Both aqueous and 50% ethanol extract of the aforementioned plants showed a significant inhibition.     

In vitro antimicrobial activity of plant extracts against Pseudomonas syringae pv. actinidiae causal agent of bacterial canker in kiwifruit

Abstract

Pseudomonas syringae pv. actinidiae (Psa), the causal agent of bacterial canker of kiwifruit, is considered the main pathogen of yellow-, green- and red-fleshed kiwifruit. All major kiwifruit producing countries in the world have been affected by this bacterial pathogen, leading to substantial economic losses. The control of bacterial canker of kiwifruit is based only on preventive methods or on the use of copper compounds that can cause phytotoxicity problems. In this study, the in vitro antibacterial activity of seven different plant extracts against eight Psa strains has been evaluated. The inhibition of 100% of the Psa growth was observed, after 24?h, for the extracts of Polygonum cuspidatum roots (POL-roots), Hypericum perforatum roots elicited with chitosan oligosaccharides (HYP-COS roots) and non-fermented grape pomace (ITA-pomace). The strongest antibacterial activity was exhibited by POL-roots, with a geometric mean of minimum inhibitory concentration of 100% of growth (GMMIC₁₀₀) of 105.11 µg/mL after 24?h, and with a GMMIC₁₀₀ value of 148.65 µg/mL after 48?h. Moreover, POL-roots extract showed the best bactericidal activity with a GMMBC of 210.22 µg/mL. No phytotoxic activity was observed up to 15 days in the leaves of Actinidia chinensis “Belen” treated with plant extracts at 500 µg/mL.