Climate change will probably influence the occurrence, prevalence and severity of plant diseases. This will also affect disease management with regard to timing, preference and efficacy of chemical, physical and biological measures of control and their utilization within integrated pest management (IPM) strategies. Prediction of future requirements in disease management is of great interest for agroindustries, extension services and practical farmers. A comprehensive analysis of potential climate‐change effects on disease control is difficult because current knowledge is limited and fragmented. This review reveals that certain existing preventive plant protection measures, such as use of a diversity of crop species in cropping systems, adjustment of sowing or planting dates, use of crop cultivars with superior resistance and/or tolerance to diseases and abiotic stress, use of reliable tools to forecast disease epidemics, application of IPM strategies, and effective quarantine systems, may become particularly important in the future. Effective crop protection technologies are available and will provide appropriate tools to adapt to altered climatic conditions, although the complexity of future risks for plant disease management may be considerable, particularly if new crops are introduced in an area. Overall, the challenge of adapting disease control measures to climate change is not likely to be fundamentally different from the adjustments to technological innovations or changes in the economic framework already required in current crop protection. Potential beneficial effects of climate change, such as longer growing seasons, fewer frosts and shifted precipitation patterns, must not be neglected, as they could counteract the presumed enhancement of particular diseases.

The introduction of high-yielding and hybrid cultivars and the opening of new markets in the food and feed sector have steadily increased rapeseed production since the 1980s in the main production regions, Canada, Europe, China, India, and Australia. Since the 1990s, however, the average growth rate of yields has declined in Europe and Australia, which has been associated with a less effective control of biotic stresses. A global survey including the knowledge of 22 experts from 10 countries revealed a total of 16 diseases, 37 insect pests, several species of nematodes, and slugs currently affecting rapeseed production globally. A ranking of the top 10 most important biotic stresses in the four global regions where Brassica napus is grown (Canada, China, Europe, Australia) indicated an increase in several important stresses and distinct regional differences in the priority of prevailing diseases and pests. A stronger overlap exists among diseases, with Sclerotinia stem rot, Phoma stem canker, and clubroot occurring in all the four global regions on the top 10 list, while the range of prevailing insect pests was more diverse among the regions, with no top 10 insect playing an equally important role worldwide. Management options are substantially broader in disease than in pest control, making the latter the larger challenge. Since common integrated pest management (IPM) tools such as crop rotation, soil management, resistant cultivars or biocontrol are ineffective or not available, insect control largely relies on insecticides. Increasing restrictions on insecticide use, particularly in Europe, and losses in insecticide efficacy threaten the profitability of oilseed rape production and its role as an important break crop in cereal dominated cropping systems. Since the survival time of insects in the absence of their main host is relatively short (<1 year), a regional synchronization of cropping schemes resulting in one or more years without the crop could lead to a substantial disruption of regional insect populations. If rotation schemes were implemented on the landscape instead the farm level, by coordination among growers in zones covering the range distances of insect pests, an efficient and chemical low management strategy could be established and enable a more sustainable rapeseed production in the future.

Fusarium species are common pathogens on maize and reduce the product quality through contamination with mycotoxins thus jeopardizing safety of both animal feed and human food products. Monitoring of Fusarium infected maize ears and stalks was conducted in Germany to determine the range of Fusarium species present in the field and to assess the impact of tillage, crop rotation, and weather conditions on the frequency of Fusarium species. From 2016 till 2018, a total of 387 infected ears and 190 stalk segments from 58 locations in Germany were collected. For each sample location, site-specific agronomic data on tillage and previous crops as well as meteorological data on precipitation, air temperature, and relative humidity during the vegetation period were recorded. The most frequent Fusarium species detected in maize ears were Fusarium graminearum, F. verticillioides and F. temperatum, whereas, F. graminearum, F. equiseti, F. culmorum, and F. temperatum were the species prevailing on maize stalks. Differences in the local species composition were found to be primarily associated with weather variations between the years and the microclimate at the different locations. The results indicate that mean temperature and precipitation in July, during flowering, has the strongest impact on the local range of Fusarium spp. on ears, whereas the incidence of Fusarium species on stalks is mostly affected by weather conditions during September. Ploughing significantly reduced the infection with F. graminearum and F. temperatum, while crop rotation exerted only minor effects.

Copper-containing fungicides have been used in agriculture since 1885. The divalent copper ion is a nonbiodegradable multisite inhibitor that has a strictly protective, nonsystemic effect on plants. Copper-containing plant protection products currently approved in Germany contain copper oxychloride, copper hydroxide, and tribasic copper sulfate. Copper is primarily used to control oomycete pathogens in grapevine, hop, potato, and fungal diseases in fruit production. In the environment, copper is highly persistent and toxic to nontarget organisms. The latter applies for terrestric and aquatic organisms such as earthworms, insects, birds, fish, Daphnia, and algae. Hence, copper fungicides are currently classified in the European Union as candidates for substitution. Pertinently, copper also exhibits significant mammalian toxicity (median lethal dose oral = 300–2500 mg/kg body wt in rats). To date, organic production still profoundly relies on the use of copper fungicides. Attempts to reduce doses of copper applications and the search for copper substitutes have not been successful. Copper compounds compared with modern synthetic fungicides with similar areas of use display significantly higher risks for honey bees (3- to 20-fold), beneficial insects (6- to 2000-fold), birds (2- to 13-fold), and mammals (up to 17-fold). These data contradict current views that crop protection in organic farming is associated with lower environmental or health risks. Further limitations in the range and use of modern single-site fungicides may force conventional production to fill the gaps with copper fungicides to counteract fungicide resistance. In contrast to the European Union Green Deal goals, the intended expansion of organic farming in Europe would further enhance the use of copper fungicides and hence increase the overall risks of chemical crop protection in Europe. Environ Toxicol Chem 2024;43:19–30. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.