Review: Resistance as a concomitant of modern crop protection

This paper reviews the impact of resistance to fungicides and insecticides/acaricides on the way crop protection is practised. It is now clear that resistance can develop to virtually any crop-protection product, in any pest, fungal pathogen or even weed. As a limiting factor in crop protection, it is a fact of life. A positive side-effect is the precision with which products are used today, with increasing implementation of Integrated Pest Management (IPM) programmes. This is a vital step towards sustainability. This paper describes: past experiences; current status of resistance; how resistance management influences current crop protection practices; regulatory aspects; and the outlook for the future. It concludes that EU regulations on resistance management must be simple and workable. Chemicals will continue to have a central role in optimising yields from the world's crops, as new tools, including biotechnology, become available for crop protection and resistance management. The crop-protection industry's innovations and product stewardship programmes will contribute to sustainable agriculture. This will provide continued benefits to users, the environment and society. ©1997 SCI     

Implementing a globally harmonized risk assessment‐based approach for regulatory decision‐making of crop protection products

A global, harmonized evaluation system for crop protection chemicals based on exposure and risk will improve the ability to inform risk management decisions and better support innovation. This would be achieved through harmonized risk assessment‐based regulatory decision‐making realized through the application of the best available science, via integration of new methods and traditional data to create tailored exposure‐driven risk assessments. A requirement to achieve success is a structure that encourages direct communication between the regulatory community and the regulated industry, which would enable a more rapid incorporation of new technologies and advancing science. An approach that emulates the International Conference of Harmonization (ICH) for pharmaceuticals would bring together regulatory authorities and the regulated industry along with relevant experts from academia and Non‐Governmental Organizations to discuss scientific and technical advances and their implementation. These discussions would also encourage the elimination of outmoded practices that no longer serve a purpose resulting in more uniform testing requirements and best practices for data evaluation to support safe use and scientifically defensible human health and environmental risk assessments. New and developing technologies offer exciting opportunities to improve the current toxicity testing paradigms to provide better solutions and diminish animal testing. Implementation of a harmonized approach will increase the speed, efficiency and accuracy of regulatory decision‐making for human health and environmental protection while increasing the efficiency of providing safe and effective innovative products to the agriculture community. © 2020 Society of Chemical Industry     

Statistical aspects of efficacy evaluation of plant protection products in field trials – a comment on EPPO Standard PP1/152

The evaluation of plant protection product efficacy in field trials is a complex task. Several aspects of the statistical evaluation are discussed in this paper, along with a recommendation to modify EPPO Standard PP1/152. Confidence intervals should be preferred over significance tests to avoid contradictions between 'statistical significance' and 'biological relevance'. Efficacy should first be demonstrated, by comparison of a new product with a well chosen reference product, using a test of non-inferiority. When non-inferiority has been established, a test of superiority can follow. Both can simply be obtained by one-sided confidence intervals of µ_Reference – µ_Product or µ_Reference / µ_Product, where µ_Reference and µ_Product are the means for the reference and the product, respectively. Confidence intervals for the ratio are easier to interpret because of the definition of percentage change. The evaluation that a trial is realistic and coherent should be performed according to the present EPPO guideline before any analysis of efficacy is made. Efficacy data from trial series should be preferred over individual trials because this represents different sites and increased sample size (number of sites and number of plots). The treatments-by-sites interaction should be modelled as a random effect in a mixed model. Software in R is available for these suggested analyses.     

Authorization requirements to improve safety and efficacy in developmental products for biological plant protection1

In Germany, as in other countries around the world, plant protection products need to be authorized before being placed on the market. This is true not only for chemicals but also for biological products, which, in Germany, cover microorganisms (including fungi) and viruses. Therefore, an importer or manufacturer of a plant protection product must apply for authorization and submit detailed data and information to prove conformity with the authorization requirements. Beside other important subjects, it must be clearly demonstrated that a plant protection product fulfils the demands of its user as far as its intended fields of use are concerned, and that there are no adverse effects on human and animal (livestock) health, on groundwater or on other aspects of the environment. Although there is an agreement between responsible applicants, authorization holders and competent authorities that such facts should be known, it must be admitted that there are problems with details. Nevertheless, instead of being resistant to official demands for efficacy and safety of biological plant protection products, it would be better to accept them as a guide for the development of good products for the market and as a means of preventing others from being distributed, which could spoil the reputation of biological control.     

Big Data for weed control and crop protection

Farmers have access to many data‐intensive technologies to help them monitor and control weeds and pests. Data collection, data modelling and analysis, and data sharing have become core challenges in weed control and crop protection. We review the challenges and opportunities of Big Data in agriculture: the nature of data collected, Big Data analytics and tools to present the analyses that allow improved crop management decisions for weed control and crop protection. Big Data storage and querying incurs significant challenges, due to the need to distribute data across several machines, as well as due to constantly growing and evolving data from different sources. Semantic technologies are helpful when data from several sources are combined, which involves the challenge of detecting interactions of potential agronomic importance and establishing relationships between data items in terms of meanings and units. Data ownership is analysed using the ethical matrix method to identify the concerns of farmers, agribusiness owners, consumers and the environment. Big Data analytics models are outlined, together with numerical algorithms for training them. Advances and tools to present processed Big Data in the form of actionable information to farmers are reviewed, and a success story from the Netherlands is highlighted. Finally, it is argued that the potential utility of Big Data for weed control is large, especially for invasive, parasitic and herbicide‐resistant weeds. This potential can only be realised when agricultural scientists collaborate with data scientists and when organisational, ethical and legal arrangements of data sharing are established.     

Are honeybees suitable surrogates for use in pesticide risk assessment for non‐Apis bees?

Historically, bee regulatory risk assessment for pesticides has centred on the European honeybee (Apis mellifera), primarily due to its availability and adaptability to laboratory conditions. Recently, there have been efforts to develop a battery of laboratory toxicity tests for a range of non‐Apis bee species to directly assess the risk to them. However, it is not clear whether the substantial investment associated with the development and implementation of such routine screening will actually improve the level of protection of non‐Apis bees. We argue, using published acute toxicity data from a range of bee species and standard regulatory exposure scenarios, that current first‐tier honeybee acute risk assessment schemes utilised by regulatory authorities are protective of other bee species and further tests should be conducted only in cases of concern. We propose similar analysis of alternative exposure scenarios (chronic and developmental) once reliable data for non‐Apis bees are available to expand our approach to these scenarios. In addition, we propose that in silico (simulation) approaches can then be used to address population‐level effects in more field‐realistic scenarios. Such an approach could lead to a protective, but also workable, risk assessment for non‐Apis species while contributing to pollination security in agricultural landscapes around the globe. © 2019 Society of Chemical Industry     

Guidance for the assessment of risks to bees from the use of plant protection products under the framework of Council Directive 91/414 and Regulation 1107/2009

About 15 years have passed since the implementation of Directive 91/414/EEC and the regulatory framework with regard to pesticide use and environmental protection aims, as well as the plant protection techniques involving pesticides, have evolved over this period. In the case of honey bees, further developments and updates with regards to larval testing have been undertaken. Experimental protocols for semi‐field and field testing have been reviewed in detail. Finally, a dedicated risk assessment scheme has been developed for seed coating and soil applications that involve systemic compounds. A revision of the original EPPO Standards: the Risk Assessment Scheme PP 3/10(2) Honeybees and the test guidelines PP1/170 (3) Side‐effects on honeybees has thus been undertaken in order to benefit from these improvements. This paper aims to provide the details of the reasoning on which the revised risk assessment scheme relies as well as providing the necessary references to the data which have been reviewed in the context of this revision.     

Environmental risk assessment of plant protection products: an approach to the development of guidelines

To aid the assessment of potential environmental side-effects arising from the use of plant protection products, a general framework for decision-making schemes is proposed. This should provide a consistent basis for the evaluation of different products, affecting the environment in different ways. Schemes constructed by this approach should indicate areas of uncertainty, highlight aspects on which expert knowledge is essential, and identify the data needed and how to interpret them. The proposed framework is sequential, comprising a series of stages, from the pattern of use of the product and its properties, to exposure of wildlife, calculation of the probability that adverse effects will occur, and judgements about their acceptability. This can be applied separately to effects on various components of the environment. A convenient format for decision-making schemes is a sequence of linked questions leading to a classification of the environmental consequences. This is adaptable to more complex versions (e.g. a computer-based expert system) or simpler, abbreviated evaluation using safety factors.     

Natural products: a strategic lead generation approach in crop protection discovery

With the anticipated population growth in the coming decades, the changing regulatory environment, and the continued emergence of resistance to commercial pesticides, there is a constant need to discover new lead chemistries with novel modes of action. We have established a portfolio of approaches to accelerate lead generation. One of these approaches capitalizes on the rich bioactivity of natural products (NPs), highlighted by the numerous examples of NP‐based crop protection compounds. Within Corteva Agriscience and the affiliated preceding companies, NPs have been a fruitful approach, for nearly three decades, to identifying and bringing to the market crop protection products inspired by or originating from NPs, . Included in these NP‐based crop protection products are the spinosyns family of insecticides, and those from more recent areas of NP‐based fungicidal chemistry, as highlighted in this perspective. © 2019 Society of Chemical Industry     

Towards a tiered test strategy for plant protection products to address mixture toxicity by alternative approaches in human health assessment

Plant protection products (PPPs) consist of pesticide active substances and co‐formulants. Generally, active substance effects are assumed to dominate in PPP toxicity. Nevertheless, co‐formulants may well affect the toxicity of PPPs via toxicodynamic and toxicokinetic interaction. To account for potential mixture effects and improve PPP data requirements for application in risk assessment, a tiered test strategy is proposed. The strategy is based on a comparison of PPP and active substance toxicity, which enables the prioritisation of PPPs for further testing, adaptation of the toxicological threshold value or removal of toxic co‐formulants from the PPP. Moreover, it focuses on the integrative assessment of existing information and newly generated data using alternative test methods. The proposed strategy will improve PPP toxicological assessment by accounting for mixture toxicity, providing a set of regulatory options for risk assessment and the necessary data for hazard assessment. The predictivity of alternative methods for PPPs will improve by evaluation of their reliability and uncertainty. © 2020 The Authors. Pest Management Science published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.     

Mapping potential exposure to drift of plant protection products*

A proposal for a practical, site‐specific approach for farmers has been developed to fulfil the drift restrictions and directions imposed on a registered plant protection product. The approach is based on exposure potential maps, primarily taking account of regional and local application conditions that reduce non‐target exposure. Firstly, the maps are focused on the spray drift exposure pathway. Using geographically referenced data, we have developed four exposure indicators that allow classification of potential non‐target exposure on the basis of local application conditions. This enables us to manage product application restrictions on a field‐to‐field basis by means of the exposure class to which each field is assigned. This easy‐to‐understand information can be distributed as paper maps or as digital maps to the farmer. The farmer himself no longer needs to assess whether local conditions reduce non‐target exposure. All calculations are carried out using very detailed topographic data which suit scales from 1:10 000 to 1:25 000. Processing and analysis of the GeoData is realized through GIS technology.     

Removing constraints to sustainable food production: new ways to exploit secondary metabolism from companion planting and GM

The entire process of agricultural and horticultural food production is unsustainable as practiced by current highly intensive industrial systems. Energy consumption is particularly intensive for cultivation, and for fertilizer production and its incorporation into soil. Provision of nitrogen contributes a major source of the greenhouse gas, N₂O. All losses due to pests, diseases and weeds are of food for which the carbon footprint has already been committed and so crop protection becomes an even greater concern. The rapidly increasing global need for food and the aggravation of associated problems by the effects of climate change create a need for new and sustainable crop protection. The overall requirement for sustainability is to remove seasonal inputs, and consequently all crop protection will need to be delivered via the seed or other planting material. Although genetic modification (GM) has transformed the prospects of sustainable crop protection, considerably more development is essential for the realisation of the full potential of GM and thereby consumer acceptability. Secondary plant metabolism offers wider and perhaps more robust new crop protection via GM and can be accomplished without associated yield loss because of the low level of photosynthate diverted for plant defence by secondary metabolism. Toxic mechanisms can continue to be targeted but exploiting non‐toxic regulatory and signalling mechanisms should be the ultimate objective. There are many problems facing these proposals, both technical and social, and these are discussed but it is certainly not possible to stay where we are in terms of sustainability. The evidence for success is mounting and the technical opportunities from secondary plant metabolism are discussed here. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Regulation of semiochemicals — global aspects

A general awareness of environmental concerns, an increasing chemophobic populace and the reregistration of pesticides, both in the United States and in the European Community, with the concomitant loss of many pest control chemicals through cancellation of their registrations has provided an impetus for the research, development and commercialization of alternative, environmentally benign and safer plant protection products. Amongst such alternatives are pheromones, a class of semiochemicals whose commercial development is being championed by a neophyte industry made up, for the most part, of undercapitalized entrepreneurial companies for whom the major hurdle to the introduction of products into the marketplace is the time and cost required to complete the regulatory process. That pheromones and other semiochemicals are different from chemical insecticides has been recognized by several national regulatory agencies and the Food and Agricultural Organization of the United Nations [FAO]. Although these regulatory authorities have made significant contributions towards reducing the data requirements and hence the cost of pheromone product registration, it is widely felt that more can, and should be done to further expedite and harmonize pheromone regulation. The adoption of a structure/activity approach to the evaluation of health and environmental risks for types of lepidopteran pheromones together with a 90-day evaluation time-frame. This approach would satisfy the regulatory authorities' risk assessment for food and environmental safety while substantially reducing the cost to the registrants and expediting the registration. It is proposed that this approach be tested first in an actual product application to the US Environmental Protection Agency [EPA], with subsequent applications to other regulatory authorities. A database which could be modified already exists within the EPA and as other databases are incorporated, and shared with other regulatory authorities, harmonization of the regulation of pheromones may be possible. The application of this structure/activity approach should be expanded to other types of semiochemicals as the database is enlarged.     

Evaluation of natural diatomaceous earth deposits from south‐eastern Europe for stored‐grain protection: the effect of particle size

BACKGROUND: The use of diatomaceous earths (DEs) provides a promising alternative to the use of contact insecticides in stored‐product IPM. Geographical origin and the physical properties of a given DE may affect its insecticidal activity. In the present study, DE samples were collected from different locations of south‐eastern Europe, and their efficacy was evaluated in the laboratory against Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujiidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). In addition, three fractions comprising particles of different size were obtained from each DE sample and assessed with regards to their effectiveness against the above stored‐product insect pests. RESULTS: DE from the Greek region of Elassona was the most effective against C. ferrugineus and S. oryzae, whereas the DE Kolubara 518, mined in the Serbian region of Kolubara, was the most effective against R. dominica. Smaller particles were more effective than larger particles against the three tested species, although significant differences in the efficacy of fractions containing particles of 0–150 µm and particles with sizes of < 45 µm were not always recorded. CONCLUSIONS: Deposits from south‐eastern Europe appeared to be very effective against the tested species, and therefore this region should be further evaluated as a source of development of commercial products. Particle size is a physical property that should always be taken into account during the DE manufacturing process, as it can strongly influence the insecticidal action of a given product. Copyright © 2009 Society of Chemical Industry     

Towards dsRNA-integrated protection of medical Cannabis crops: considering human safety,recent- and developing RNAi methods,and research inroads

Owing to the expanding industry of medical Cannabis, we discuss recent milestones in RNA interference (RNAi)-based crop protection research and development that are transferable to medical Cannabis cultivation. Recent and prospective increases in pest pressure in both indoor and outdoor Cannabis production systems, and the need for effective nonchemical pest control technologies (particularly crucial in the context of cultivating plants for medical purposes), are discussed. We support the idea that developing RNAi tactics towards protection of medical Cannabis could play a major role in maximizing success in this continuously expanding industry. However, there remain critical knowledge gaps, especially with regard to RNA pesticide biosafety from a human toxicological viewpoint, as a result of the medical context of Cannabis product use. Furthermore, efforts are needed to optimize transformation and micropropagation of Cannabis plants, examine cutting edge RNAi techniques for various Cannabis–pest scenarios, and investigate the combined application of RNAi- and biological control tactics in medical Cannabis cultivation. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Scenario studies for future agriculture and crop protection

The history of crop protection has shown two shifts of focus. In the second half of this century, attention shifted from the pathogen to the pathosystem, and at present we are witnessing a further shift to a focus on the whole production system. So, crop protection is now seen as just one activity among many in agricultural production systems and improvement of crop protection is no longer seen as separate from goals such as maximizing yield and minimizing inputs, as for example nitrate use per unit of product and use of pesticides per unit of land. To explore options for future crop protection in conjunction with other production goals, scenario studies can be useful tools. Scenario studies may be used for the evaluation of technologies or may comprise feasibility analyses of land use at various aggregation levels. The methodology of scenario studies is explained in this paper and some examples are described. It is demonstrated how useful organised thinking about the future can be.     

Review of anthraquinone applications for pest management and agricultural crop protection

We have reviewed published anthraquinone applications for international pest management and agricultural crop protection from 1943 to 2016. Anthraquinone (AQ) is commonly found in dyes, pigments and many plants and organisms. Avian repellent research with AQ began in the 1940s. In the context of pest management, AQ is currently used as a chemical repellent, perch deterrent, insecticide and feeding deterrent in many wild birds, and in some mammals, insects and fishes. Criteria for evaluation of effective chemical repellents include efficacy, potential for wildlife hazards, phytotoxicity and environmental persistence. As a biopesticide, AQ often meets these criteria of efficacy for the non‐lethal management of agricultural depredation caused by wildlife. We summarize published applications of AQ for the protection of newly planted and maturing crops from pest birds. Conventional applications of AQ‐based repellents include preplant seed treatments [e.g. corn (Zea mays L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.), wheat (Triticum spp.), millet (Panicum spp.), sorghum (Sorghum bicolor L.), pelletized feed and forest tree species] and foliar applications for rice, sunflower, lettuce (Lactuca sativa L.), turf, sugar beets (Beta vulgaris L.), soybean (Glycine max L.), sweet corn and nursery, fruit and nut crops. In addition to agricultural repellent applications, AQ has also been used to treat toxicants for the protection of non‐target birds. Few studies have demonstrated AQ repellency in mammals, including wild boar (Sus scrofa, L.), thirteen‐lined ground squirrels (Ictidomys tridecemlineatus, Mitchill), black‐tailed prairie dogs (Cyomys ludovicainus, Ord.), common voles (Microtus arvalis, Pallas), house mice (Mus musculus, L.), Tristram's jirds (Meriones tristrami, Thomas) and black rats (Rattus rattus L.). Natural sources of AQ and its derivatives have also been identified as insecticides and insect repellents. As a natural or synthetic biopesticide, AQ is a promising candidate for many contexts of non‐lethal and insecticidal pest management. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.     

Integrated crop management, the basis for environment friendly crop protection of potatoes

Relatively large amounts of pesticides are needed to control diseases and pests in modern, intensive potato production. Integrated crop management offers a way of reducing the need for pesticides. It aims to reduce costs and improve the quality of the product and of the production methods, while maintaining soil fertility and the quality of the environment. The components of integrated crop management are described. Prevention of diseases and pests has high priority. If diseases or pests are present, non-chemical control methods are preferred and chemical control is based on economic criteria and the monitoring of the soil and crops. The contribution of integrated crop management to the control of two important fungal diseases, late blight (Phytophthora infestans), and stem canker (Rhizoctonia solani) and of one pest, potato cyst nematode (Globodera spp..) is described. The prospects for further development of integrated crop protection are discussed.     

Effects of a commercial neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) extract on<Emphasis Type="Italic">Streblote panda</Emphasis> larvae

Biological effects of a commercial formulation of azadirachtin, Align^TM, were assessed onStreblote panda Hübner [1820] (Lasiocampidae) first instars by means of choice and nochoice bioassays. Survival, development, and food consumption were recorded. The product tested did not show clear antifeedant effects, but produced dose-dependent larval mortality. All treatments resulted in significant inhibition of growth, presumably through endocrine regulatory effects. At higher doses assayed the product appears to have direct toxic effects. Our results suggest that Align^TM may be used in IPM programs forS. panda and should be evaluated for efficacy under field conditions. http://www.phytoparasitica.org posting July 10, 2003.     

Biological control in Hungary: present situation and possibilities1

Biological control has already achieved certain results in Hungary, especially against soil-borne fungi and glasshouse pests. Nevertheless, experience has shown that locally found biological agents, however effective, could not be developed into registered, ready-for-sale plant protection products because of the lack of companies willing to invest. Biological control in Hungary is therefore limited to the conservation of natural antagonistic flora and fauna and to the application of imported biopesticides and bioagents, which are subject in Hungary to a registration procedure similar to that for chemical plant protection products. Current work includes the development of an anti-nematode product from a local strain of Arthrobotrys oligospora, application techniques for a local mirid Dicyphus hyalinipennis against insect pests, studies with native and imported strains of the nematodes Steinernema and Heterorhabditis against soil-borne insect pests, and introduction techniques for the chrysomelid Zygogramma sutularis against the weed Ambrosia elatior.