In vitro efficacy of herbal plant extracts on some phytopathogenic fungi

Abstract

Crops are subject to yield losses caused by the presence of pests whose species and population diversity are changing with climate warming. The use of agrochemicals is still the most effective method of plant protection against diseases and pests. However, the intensive use of pesticides in some EU countries makes it necessary to search for alternative methods that can be applied in plant protection for consumer and environmental safety. The aim of the study was the laboratory evaluation of the fungistatic effect of extracts of herbal plants occurring in natural state in Poland: horseradish (Armoracia rusticana L.), yarrow (Achillea millefolium L.) and tansy (Tanacetum vulgare L.) on selected polyphagic phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, Colletotrichum coccodes and Fusarium oxysporum). In this study, 5%, 10% and 20% concentrations of herbal water-extract extracts were applied to evaluate their effects on linear growth of fungi and inhibition of their growth relative to control. Total content of polyphenols and flavonoids was assessed in the extracts using spectrophotometry, and their antioxidant activity by applying the synthetic DPPH radical. The plant extracts of tansy and yarrow leaves were characterized by a higher content of polyphenols and flavonoids compared to horseradish leaf extracts; they also had a higher antioxidant activity. Plant extracts inhibited the growth of fungi to a different extent, depending on the species of fungus, type of extract, its concentration and duration of action. The strongest fungistatic effect was recorded for tansy and yarrow extracts, while the weakest for the extract of horseradish leaves. Plant extracts showed the weakest effect against Botrytis cinerea, inhibiting the development of this fungus only during the first days of the experiment. The present research is a preliminary study that will be used in the further to develop a biological preparation for the protection of agricultural and horticultural plants against fungal pathogens.

Antifungal Potency of Amaranth Leaf Extract: An In Vitro Study

“…The present study showed no antifungal effect against C. coccodes, and a stimulating effect on mycelial surface growth was even observed. The growth of this species was also poorly inhibited by other plant extracts, including extracts from plants with high biocidal potential [13]. Carminate et al [41] also indicated the great potential of Amaranthus viridis in controlling F. solani f. sp.…”

“…Studies on the antifungal effect of various plant extracts against F. oxysporum have been conducted by many researchers [12,17] who showed that F. oxysporum was not very sensitive to the effects of extracts from medicinal plants. Kursa et al [13] showed that 20% ethanol extracts of tansy, yarrow and horseradish, considered potent against many phytopathogens, inhibited the surface growth of F. oxysporum only at the level of 24.7-26.56%, and only in the first days of the experiment. The strong inhibitory effect of the amaranth extract was recorded against F. equiseti, mainly in relation to the extracts of A. retroflexus (TR) and A. hypochondriacus × hybrisus (PH).…”

“…The study evaluated the effects of ethanol extracts of amaranth leaves (Polish and Turkish species: PC, PH, TR, TH) at concentrations of 10% and 15% on the linear growth of the test fungi. The method of poisoned substrates was used in the study, which is recommended to test chemical agents under laboratory conditions [13]. The method consisted of adding the test substance to sterile potato dextrose agar (PDA) medium cooled to 50 • C and inoculating the fungus species on the solidified medium.…”

“…Many of them are based on plant extracts enriched with minerals and beneficial microorganisms [10]. Numerous studies have been conducted on plants containing biologically active compounds that inhibit the growth of pathogenic microorganisms [11][12][13]. Many plant species, mainly herbs, are already promising sources of bioactive substances such as phenols, anthocyanins, flavonoids or carotenoids, which are used to extend the shelf life of meals and processed foods [14][15][16][17].…”

“…In recent decades, the antimicrobial and antifungal properties of various extracts and their components, including essential oils, have been tested and attention has been drawn to the application of these natural raw materials as alternative plant protection products, because they are biodegradable and non-toxic to the environment [18]. Some of them contain natural products from secondary metabolic pathways that allow plants to protect themselves from their natural enemies [13]. In addition to many herbal plants occurring in the natural environment, certain pseudo-cereals are also rich in a wide range of compounds, e.g., flavonoids and phenolic acids, present not only in grains, but also in other aerial plant parts (leaves, stems) [19,20].…”