Scientific evidence of sustainable plant disease protection strategies for oilseed rape (Brassica napus) in Sweden: a systematic map
Oilseed rape (OSR; Brassica napus L.) is a highly valued crop for food, feed and industrial use. It is primarily grown in temperate climates, and over recent decades, its area of production and profitability have increased. Concurrently, several diseases negatively impact OSR production. Diseases caused by soil-borne pathogens, pose a risk of substantial yield loss since crop rotation schemes have become narrow as the time lapse between OSR crops in a field has been shortened. The aims of this paper were to provide an overview of plant protection measures available for OSR production and to identify knowledge gaps and areas where more research is needed.
This systematic map builds on a previously published protocol and follows the ROSES reporting standard. The search strategy was developed in collaboration with stakeholders and designed to cover available scientific evidence for OSR disease management in climate zones relevant for Scandinavian crop production (Dfc, Dfb, Cfb and Cfa in the Köppen-Geiger climate classification). Five scientific databases were used to identify peer-reviewed literature, complemented by additional searches performed in grey literature. Articles were screened at three stages: the title, abstract and full text. The eligible publications included studies of OSR crops, and all measures to control crop disease in agricultural fields were considered eligible interventions. The comparator was intervention and no intervention, and the yield per unit area, disease suppression or an increase in crop quality were determined to be outcomes of interventions. A basic assessment of the experimental design of each study was performed to assess its eligibility. All articles were coded based on the following categories: the location and climate zone, disease, pathogen, intervention and management method, outcome and study design. Articles not reporting original data but judged to be relevant (i.e., review papers, books and notes of registration of cultivars) were saved in a separate category called “books, reviews and reports”.
A total of 4633 articles were collected through systematic searches. After duplicates were removed, 3513 articles were included in the screening process. After screening at the title and abstract levels, 897 articles were evaluated at the full text level, and 118 articles comprised the studies that met the eligibility criteria of the systematic map. The country (Canada) and region (Europe) with the largest OSR crop production areas also contributed the highest number of articles. In total, 17 different diseases were reported, with black leg (syn. Phoma stem canker) being the most studied disease. Nineteen different intervention methods or management types were examined. Cultivar resistance and pesticide application were the most studied control measures.
We report scientific studies on plant disease protection measures for OSR based on field trials where the results are intended to be directly implemented in crop production management. The map clearly provides an overview of research progress throughout the time period chosen, and it identifies knowledge gaps regarding important diseases where only a few studies have been published, for example, diseases caused by viruses.
Brassica napus, Rapeseed, Canola, Plant pathology
Efficient and sustainable plant protection is of great economic and ecological significance for global crop production. A number of challenges, e.g. climate change, population growth and global trade, put increasing demands on future crop production and crop protection. This necessitates an increase in crop productivity with less environmental impact while maintaining good food quality and food security. To meet these challenges, it is essential that the recommendations provided to growers are efficient and correct, which can only be ensured by evidence-based recommendations based on outcomes from scientific studies.
Methods and output
The aim of these systematic maps is to compile scientific evidence for different plant disease protection strategies for the main arable crops grown in Sweden. Six major crops (wheat, barley, oat, potato, sugar beet and oilseed rape) have been selected based on the area under production, the annual production, the economic importance, and the amount of pesticide used against diseases in these crops in Sweden. All methods to manage diseases will be considered, including cropping system, pesticide application, biological control methods, as well as combinations of methods and integrated pest management. These systematic maps will only deal with field studies of relevance for agricultural practices in Sweden, although we expect that the results will be applicable for northern Europe as a whole. The main outcome to be used will be productivity measured as yield per area. Plant health and pathogen reduction will be included as a proxy for potential increase in crop quality and yield. This will provide a systematic overview of the plant disease protection measures that have been reported in the scientific literature. The study will result in one searchable database per crop that may be used as a catalogue of evidence for researchers and stakeholders, especially authorities and advisory organizations. The systematic maps will aid in the identification of areas that need further research and guide funding agencies and policymakers when deciding where research resources should be allocated. It will also help to select topics for future systematic reviews and meta-studies within the field of plant protection.