Bernhard Speiser

Control of Downy Mildew of Grapevine with Potassium Phosphonate: Effectivity and Phosphonate Residues in Wine

ABSTRACT In organic viticulture, downy mildew is often controlled with copper. Because copper is known to be phytotoxic and to accumulate in the soil, the replacement of copper is a major concern of organic agriculture. Here, 13 on-farm trials to evaluate potassium phosphonate as an alternative fungicide to copper are reported. Residues were determined in 53 samples of wine. Potassium phosphonate was effective against downy mildew, but not against powdery mildew and red fire disease. Treatment effectivity against downy mildew increased significantly with the amounts of potassium phosphonate applied. Phosphonate residues in wine were highly correlated with the total amount of potassium phosphonate applied during the vegetation period, but not with the date of the last application. Under equal treatment of the grapes with potassium phosphonate, red wines contained approximately 25% more phosphonate than white wines, but this was not sufficient to result in detectable differences between red and white wines in a random sample of wines. There were no obvious differences among grape cultivars. In conclusion, potassium phosphonate is an effective fungicide for the control of downy mildew, but the application of potassium phosphonate inevitably leads to phosphonate residues in the wine. In our view, phosphonate residues are not compatible with the reputation of organic wine among consumers, and we do recommend the use of potassium phosphonate in organic viticulture.

Sustainability assessment of GM crops in a Swiss agricultural context

The aim of this study was to provide an ex ante assessment of the sustainability of genetically modified (GM) crops under the agricultural conditions prevailing in Switzerland. The study addressed the gaps in our knowledge relating to (1) the agronomic risks/benefits in production systems under Swiss conditions (at field and rotation/orchard level), (2) the economic and socio-economic impacts associated with altered farming systems, and (3) the agro-ecological risks/benefits of GM crops (at field and rotation/orchard level). The study was based on an inventory of GM crops and traits which may be available in the next decade, and on realistic scenarios of novel agricultural practices associated with the use of GM crops in conventional, integrated, and organic farming systems in Switzerland. The technology impact assessment was conducted using an adapted version of the matrix for “comparative assessment of risks and benefits for novel agricultural systems” developed for the UK. Parameter settings were based on information from literature sources and expert workshops. In a tiered approach, sustainability criteria were defined, an inventory of potentially available, suitable GM crops was drawn up, and scenarios of baseline and novel farming systems with GM crops were developed and subsequently submitted to economic, socio-economic, and agro-ecological assessments. The project had several system boundaries, which influenced the outcomes. It was limited to the main agricultural crops used for food and feed production and focused on traits that are relevant at the field level and are likely to be commercially available within a decade from the start of the project. The study assumed that there would be no statutory restrictions on growing GM crops in all farming systems and that they would be eligible for direct payments in the same way as non-GM crops. Costs for co-existence measures were explicitly excluded and it was assumed that GM foods could be marketed in the same way as non-GM foods at equal farm gate prices. The following model GM crops were selected for this study: (1) GM maize varieties with herbicide tolerance (HT), and with resistance to the European corn borer (Ostrinia nubilalis) and the corn rootworm (Diabrotica virgifera); (2) HT wheat; (3) GM potato varieties with resistance to late blight (Phytophthora infestans), to the nematode Globodera spp., and to the Colorado beetle (Leptinotarsa decemlineata); (4) HT sugar beet with resistance to “rhizomania” (beet necrotic yellow vein virus; BNYVV); (5) apples with traditionally bred or GM resistance to scab (Venturia inaequalis), and GM apples with stacked resistance to scab and fire blight (Erwinia amylovora). Scenarios for arable rotations and apple orchards were developed on the basis of the model crops selected. The impact assessments were conducted for the entire model rotations/orchards in order to explore cumulative effects as well as effects that depend on the farming systems (organic, integrated, and conventional). In arable cropping systems, herbicide tolerance had the most significant impact on agronomic practices in integrated and conventional farming systems. HT crops enable altered soil and weed management strategies. While no-till soil management benefited soil conservation, the highly efficient weed control reduced biodiversity. These effects accumulated over time due to the high proportion of HT crops in the integrated and conventional model rotations. In organic production systems, the effects were less pronounced, mainly due to non-use of herbicides. Traits affecting resistance to pests and diseases had a minor impact on the overall performance of the systems, mainly due to the availability of alternative crop protection tools or traditionally bred varieties. The use of GM crops had only a minor effect on the overall profitability of the arable crop rotations. In apple production systems, scab and fire blight resistance had a positive impact on natural resources as well as on local ecology due to the reduced need for spray passages and pesticide use. In integrated apple production, disease resistance increased profitability slightly, whereas in the organic scenario, both scab and fire blight resistance increased the profitability of the systems substantially. In conclusion, the ecological and socio-economic impacts identified in this study were highly context sensitive and were associated mainly with altered production systems rather than with the GM crops per se.

Regulation According to EU Directive 91/414: Data Requirements and Procedure Compared with Regulation Practice in Other OECD Countries

The data requirements and the administrative procedure needed for the registration of biological plant protection products and their active ingredients (micro-organisms including viruses, plant extracts, and semiochemicals) are described for the European Union, the USA, Canada and Australia and compared between these systems. Experiences from registration procedures are compared. While data requirements and formalities are rather similar in all systems considered, the time span needed for evaluation and the possibility to predict this time span are quite different. Alternative regulatory measures existing in different regulatory systems are described and initiatives for the facilitation are presented.

Proposals for Regulation of Botanicals

Plants and plant extracts, here called ‘botanicals’, have been used for plant protection for a long time. Quantitatively, the most important botanical is pyrethrum, followed by azadirachtin, rotenone and essential oils. The current regulatory system for pesticides is often seen as a major hurdle for the market introduction of new botanicals. The EU-funded Specific Support Action project ‘REBECA’ has held a series of workshops with stakeholder representatives. The following proposals for improvement were elaborated: (1) development of a specific guidance document for botanicals; (2) adapted requirements concerning the characterisation of the active substance(s); (3) relaxations concerning identification and analytical methods for ‘impurities’; (4) adapted requirements concerning the description of manufacturing methods; (5) adapted requirements for risk assessment, taking into account the history of safe use of the substance; (6) adapted requirements concerning efficacy evaluation. During the final conference of the REBECA project, it was evaluated which proposals can be implemented easily (and therefore in a short time-span). Also, the impact on the duration of the registration process and on the costs of registration (for the applicant) were assessed for each proposal. Fenugreek, neem extract/Quassia, lecithine and laminarine were selected as representative botanicals. For these substances, the REBECA proposals would decrease registration costs substantially.

Regulation of Plant Protection in Organic Farming

Organic farming is a system approach aiming at a sustainable ecosystem, safe food, good nutrition, animal welfare and social justice. Quantitatively, organic farming is still of minor importance, but it is one of the most rapidly growing agricultural sectors worldwide. The new EU ‘organic regulation’ consists of a framework regulation, complemented by implementation rules and guidelines. Other important regulations/standards are the National Organic Program of the USA, the guidelines of the Codex Alimentarius and the basic standards of the International Federation of Organic Agriculture Movements (IFOAM). Under all these standards, plant protection is strictly regulated. Organic plant protection follows a clear hierarchy: primarily, plant health is maintained by preventative measures. Only if these methods are insufficient, plant protection products may be used. However, only a very limited range of substances is authorized (substances of plant or animal origin, micro-organisms and a few other substances). In the EU, new substances can only be authorized if they are consistent with organic farming principles, necessary for sustained production, and if they are of plant, animal, microbial or mineral origin. Case studies for the codling moth and potato late blight illustrate that the practices of organic plant protection in Europe differ significantly from one country to another. The codling moth is mainly controlled by mating disruption, Bacillus thuringiensis, and Cydia pomonella granulosis virus (CpGV). To what extent spinosad will be used in the future is not yet clear, as it was authorized for organic farming only recently. To avoid the late blight epidemic, organic farmers use a variety of management practices. Within the constraints of the market, they also avoid susceptible varieties. For direct control of late blight, copper fungicides are the only plant protection products authorized in organic farming, but they cannot be used in all EU countries, and there are quantitative restrictions in some countries.

Proposals for Regulation of Semiochemicals

Semiochemicals are substances that evoke behavioural or physiological responses. Pheromones modify the behaviour of other individuals of the same species, while allelochemicals act on individuals of different species. Pheromones are used in plant protection (i) to interfere with the mating behaviour of pests (‘mating disruption’), (ii) to attract pests to insecticidal traps or baits (‘attract and kill’), (iii) to trap pests (‘mass trapping’), and (iv) to monitor pest populations. Semiochemicals present a particular case among active ingredients used in plant protection products, as they are the only substances not intended to kill the pest organism directly. The current regulatory system for pesticides is often seen as a major hurdle for the market introduction of new semiochemicals. The EU-funded Specific Support Action project ‘REBECA’ has held a series of workshops with stakeholder representatives. The following proposals for improvement were elaborated: (1) collective listing of the ‘straight-chained lepidopteran pheromones’ (SCLPs) in Annex I of directive 91/414/EEC; (2) treating SCLPs as ‘low risk’ substances under the new pesticides legislation; (3) relaxations concerning the identification of impurities; (4) more flexibility in the number of samples to be analysed; (5) facilitations in the risk assessment of SCLPs; (6) a procedure which will lead to facilitations in the risk assessment of other semiochemicals in the long term; (7) flexibility in efficacy evaluation; (8) harmonisation of registration requirements. During the final conference of the REBECA project, it was discussed whether the REBECA proposals can be implemented easily, and therefore in a short time-span. Also, the impact on the duration of the registration process and on the costs of registration (for the applicant) was assessed for each proposal. Among the proposals that were evaluated as relatively easy to implement, collective listing of SCLPs, relaxations concerning the identification of impurities and flexibility in efficacy evaluation have the greatest potential impact. All proposals which were evaluated as more difficult to implement have a great potential impact, but harmonisation of registration would reduce costs much more than any other proposal.

Regulatory Framework for Plant Protection in Organic Farming

Plant protection in organic farming has to simultaneously comply with two sets of regulations: regulations on organic production and pesticide legislation. This chapter describes the organic approach to plant protection, including the role of systems management versus direct interventions, the range of authorised substances and the procedures for authorising new substances and the withdrawal of old substances.