Antifungal activity of plant extracts against phytopathogenic fungi

Aqueous-methanolic extracts and acetone exudates of 24 plant species were screened for their antifungal activity against four largely spread plant pathogens possessing a broad spectrum of plant hosts - Alternaria alternata, Botrytis cinerea, Phytophthora cambivora and Fusarium oxysporum. Examination of the effect of plant extracts on mycelium growth and development of plant pathogens was done by diffusion method in vitro on PDA medium. The highest antifungal activity with an impact on the most studied pathogens was found for the acetone exudates. Among the tested exudates that of Salvia officinalis showed the highest activity against three plant pathogens tested. The exudates of Artemisia campestris, Artemisa absinthium and Clinopodium vulgare displayed activity against Fusarium oxysporum and Phytophthora cambivora. Chemical profiles of the most active exudates were determined by HPTLC and GC/MS. Non-polar substances composed mainly of flavonoid aglycones, terpenes, sterols and fatty acids were identified

Plant extracts and Trichoderma spp: possibilities for implementation in agriculture as biopesticides

AbstractThe overuse of agrochemicals and development of pesticide resistance in plant pathogens is a main challenge in conventional agriculture. The use of biopesticides based on natural substances is recognized as an effective alternative of conventional pesticides. Besides the beneficial microorganisms, some plant species can be a source of microbiologically active compounds. Among the most promising are Origanum vulgare ssp. hirtum, Centaurea finazzeri, Achillea crithmifolia, Artemisia spp, Thymus pulegioides, Tanacetum parthenium, Clinopodium vulgare, Salvia sclarea, Lavandula officinalis and Mentha piperita. The filamentous fungi from genus Trichoderma are some of the most studied biocontrol agents because of their versatile mode of action. They employ several different strategies to combat plant pathogens, like direct mycoparasitism, production of enzymes and antibiotic substances, competition, ability to induce resistance in plants to a variety of stresses. Cost-effective cultivation and mass production of Trichoderma sp. biomass and formulations will allow utilization of locally available low-cost materials, such as different wastes and by-products that could be used as a growth substrate for production of adequate biomass containing effective propagules with or without minimal adjustments to the composition of cultivation media. This review outlines the two major mass production methods - solid and liquid state fermentation of Trichoderma spp. The possibilities for development of novel products for the bioindustry are highlighted

Invasive forest pathogens in Europe: Cross-country variation in public awareness but consistency in policy acceptability

Political action can reduce introductions of diseases caused by invasive forest pathogens (IPs) and public support is important for effective prevention. The public’s awareness of IP problems and the acceptability of policies aiming to combat these pathogens were surveyed in nine European countries (N = 3469). Although awareness of specific diseases (e.g., ash dieback) varied, problem awareness and policy acceptability were similar across countries. The public was positive towards policies for informational measures and stricter standards for plant production, but less positive towards restricting public access to protected areas. Multilevel models, including individual and country level variables, revealed that media exposure was positively associated with awareness of IP problems, and strengthened the link between problem awareness and policy acceptability. Results suggest that learning about IPs through the media and recognizing the associated problems increase policy acceptability. Overall, the study elaborates on the anthropogenic dimension of diseases caused by IPs

From leaf to continent: The multi-scale distribution of an invasive cryptic pathogen complex on oak

The spatial distribution and niche differentiation of three closely related species (Erysiphe alphitoides, Erysiphe quercicola and Erysiphe hypophylla) causing oak powdery mildew was studied at scales ranging from the European continent, where they are invasive, to a single leaf. While E. alphitoides was dominant at all scales, E. quercicola and E. hypophylla had restricted geographic, stand and leaf distributions. The large-scale distributions were likely explained by climatic factors and species environmental tolerances, with E. quercicola being more frequent in warmer climates and E. hypophylla in colder climates. The extensive sampling and molecular analyses revealed the cryptic invasion of E. quercicola in nine countries from which it had not previously been recorded. The presence of the three species was also strongly affected by host factors, such as oak species and developmental stage. Segregation patterns between Erysiphe species were observed at the leaf scale, between and within leaf surfaces, suggesting competitive effects