Efficacy testing of novel organic fungicides and elicitors: from the lab to the field

Novel organic fungicides and elicitors against downy mildew on grapevines were evaluated on grapevine seedlings in a series of indoor screening experiments under controlled conditions and, if they have shown a good efficacy indoors, in a screening vineyard under field conditions. From 39 products tested under controlled conditions 10 were further examined under field conditions. All of the new products tested under field conditions showed at least partial efficacy. However, the efficacy was not good enough to protect grapevine plants sufficiently from downy mildew. For a complete re-placement of copper in plant protection against downy mildew on grapevine in organic agriculture, additional new products are needed

Impact of soil management practices on soil fertility and disease suppressiveness

Soil management practices are targeted to provide adequate crop nutrition and to ensure durable soil fertility and to avoid negative environmental impacts. Soil management also aims to reduce pest and disease pressure on crops. Organic farming is believed to increase soil suppressiveness towards soil-borne diseases as well aerial diseases. In this paper we will discuss the potential of soil manage-ment as a tool to improve disease suppressiveness in practice

Reben an verschiedenen Standorten sind unterschiedlich anfällig gegen falschen Mehltau und unterscheiden sich in der Expression von Krankheits-Verteidigungs-Genen

The influence of site on resistance of grapevine (cv. Chasselas) to Plasmopara viticola was evaluated. Grapevine leaves from three vineyards in the region of Lake Neuchâtel (Switzerland) were tested for their susceptibility to P. viticola in the lab in five successive years (2004-2008), and the expression levels of four selected defense-related genes (Glucanase, Lipoxygenase 9, 9-cis epoxycarotenoid dioxygenase, Stilbene synthase) were studied in one year. In all five years of examination, differences between sites were substantial, with plants from site HAU being much less susceptible to P. viticola than plants from site AUV. Susceptibility of plants from a third site varied from year to year. Differences in susceptibility were mirrored in the constitutive expression pattern of four defence-related genes, with samples from the HAU site clearly separated from samples of the other two sites in redundancy analysis

Entwicklung von nachhaltigen Kupfer-Alternativen: Der lange Weg von der Forschung zum Produkt

Entwicklung von nachhaltigen Kupfer-Alternativen: Der lange Weg von der Forschung zum Produkt

Crop protection strategies in European organic viticulture protection strategies in European organic viticulture

Contents - Organic viticulture in Europe - Major bottlenecks and solutions - Crop protection strategies in humid climates - Novel trends in disease contro

Identifizierung und Charakterisierung der krankheitsunterdrückenden Mikroorganismen beim Komposteinsatz

Einleitung • Bodenbürtige Krankheiten verursachen grosse Schäden und sind schwierig zu kontrollieren. • Kompost-Zugabe kann Druck durch bodenbürtige Krankheitserreger reduzieren • ABER: Nicht jeder Komposteinsatz ist erfolgreich. • Möglicher Grund ist die sich während des Kompost-Reifeprozesses laufend ändernde mikrobielle Zusammensetzung. • Es ist weitgehend noch unbekannt, welche mikrobiellen Konsortien wichtig für die suppressive Wirkung von Komposten sind

Differenzialdiagnose: Eine Methode zur Ursacheneingrenzung bei Bodenmüdigkeit

Fertile soils are highly important for arable farming. To maintain soil fertility, crop rotation including legumes is applied, particularly in stockless farms. Yet, many commercial farms report yield reductions for legumes. The aim of the present study was to evaluate whether the causes for the observed soil fatigue can be narrowed down by a bioassay (modified differential diagnosis according to Bouhot) and whether this bioassay could be a useful tool to predict the suitability of a field to grow legumes

Microbiome Research at FiBL

Overview and discussion of microbiome research at FiBL - Microbial diversity and biological soil quality after 12 years of organic and conventional cocoa production - Utilising plant-microbiome interactions to enhance resistance breeding against pathogen complexes - The Compost Microbiome - Source of Diverse Actors in Plant Protection - Microbiome diagnostics for a sustainable agricultur

The effect of an extract from mycelium of "Penicillium chrysogenum" on plant-pathogen interactions and characterisation of elicitors in this extract

In agriculture, infection of plants with microorganisms including fungi, bacteria and viruses can cause high losses of yield. Apart from a broad spectrum of indirect and direct techniques to protect plants from damage, the concept of induced resistance provides a promising strategy for the control of diseases. Preliminary studies suggested that an aqueous extract from the dry mycelium of the non-pathogenic ascomycete Penicillium chrysogenum, further called ‘Pen’, can enhance resistance of many plants against several pathogens. The objective of this thesis was to unravel whether Pen can be used as a plant activator in commercial agriculture, to study its mode of action and to narrow down the active principles in Pen. Pen protected grapevine from downy and powdery mildew (P. viticola and U. necator), tomato from early blight (P. infestans), onion from downy mildew (P. destructor) and apple tree from apple scab (V. inaequalis) under greenhouse and field conditions without having a direct fungicidal effect. The efficacy of Pen was generally comparable to traditional fungicides such as copper and sulphur and equal to or even better than well-known inducers of resistance such as BABA or BTH. The raw material for extraction of Pen was of constant quality, a prerequisite for a future application in practice. However, Pen often caused phytotoxic side effects such as small necrotic spots or, more rarely, larger necrotic areas. The development of the phytotoxic symptoms was dependent on several parameters, including concentration of Pen, the number of applications, the persistance on the plant tissue, the plant species and variety and environmental conditions. A partially purified fraction of Pen was less toxic than the crude extract. To study signal transduction pathways involved in Pen-mediated resistance, the model plant Arabidopsis thaliana was used, allowing a comparison with the mode of action of other well-known inducers. Pen protected A. thaliana from a broad range of pathogens, including an oomycete (Peronospora parasitica), two ascomycetes (Botrytis cinerea, Alternaria brassicicola) and a bacterium (Pseudomonas syringae pv. tomato DC3000). Pen was still fully protective against B. cinerea in Arabidopsis transgenes or mutants impaired in the salicylic acid (NahG, npr1), jasmonic acid (coi1), and ethylene (ein2) signalling pathway. Pen-mediated resistance against P. parasitica was reduced in the transgene NahG, but was not affected in the mutants npr1, coi1 or ein2, indicating that Pen induced resistance against P. parasitica on a salicylic acid-dependent, but NPR1-independent pathway. Pen triggered early defense-related responses such as an extracellular alkalinisation, an oxidative burst and ethylene production in suspension-cultured cells as well as in intact leaf tissue of numerous mono- and dicotyledon plant species. Cells pretreated with chitin or ergosterol were refractory to a second treatment with the same stimulus but fully responsive to Pen, indicating that Pen contains at least one unidentified elicitor (the ‘Pen-elicitor’). To develop new strategies for production of an extract without the undesired phytotoxic side effects, we aimed at purifying and characterizing the Pen-elicitor. Measuring early defense-related responses in suspension-cultured cells is a simple, fast and sensitive bioassay and was thus used as a tool for purification and characterization of the Pen-elicitor. The Pen-elicitor could only be isolated from a high but not from a low penicillin-producing strain of P. chrysogenum. The Pen-elicitor was sensitive to protease digestion, to basic hydrolysis, to oxidation by periodate and, to a less extent, to acidic hydrolysis. The Pen-elicitor was not affected by numerous other enzymes and by several chemical treatments. Reversed phase, ion exchange, size exclusion and affinity chromatography revealed that heterogeneity is a characteristic of the Pen-elicitor. Heterogeneity could not be reduced by treating Pen with several specific enzymes or chemicals which do not destroy elicitor-activity, preventing a further analysis. In conclusion, in this thesis it was shown that Pen has interesting, unique characteristics for an application as a plant protection agent in organic agriculture, provided its phytotoxic side effects can be removed. Our work on Arabidopsis thaliana has revealed that Pen has the potential to protect a plant species against a broad range of pathogens, including biotrophic as well as necrotrophic microorganisms belonging to different classes. Furthermore, Pen seems to activate defense mechanisms by way of signal transduction pathways different from known plant activators. We hypothesize that the Pen-elicitor consists of a small, distinct elicitor-active region, most likely a protein or peptide, which is part of a larger molecule varying in size and/or chemical composition. Although identification of the resistance-inducing substance would considerably facilitate to develop strategies for the preparation and processing of Pen, it is not necessarily a prerequisite for a future usage in practice. As an alternative, improved formulation as well as refined purification steps could make an application of the Pen-extract feasible

Development of plant-derived compounds as biopesticides

This chapter reviews the development of plant-derived compounds as biopesticides. It begins by providing an overview of the legal framework and authorization of plant-derived plant protection products, then goes onto discuss how these products are developed. The chapter focuses on how plant-derived substances with activity against plant pathogens can be identified, as well as the efficacy of botanicals and novelty of invention and IP protection. It also highlights the importance using raw material of a high quality for plant-derived plant protection products. The chapter also provides a section on the extraction process that is used to produce extracts suitable for plant protection products. The chapter concludes by highlighting the growing interest in environmentally friendly produced agricultural products, including plant-derived plant protection products, and also provides potential sources of further information on the subject