Understanding Yield Loss and Pathogen Biology to Improve Disease Management: Septoria Nodorum Blotch - A Case Study in Wheat

TLDR

Plant pathogens can cause up to 16 % global yield loss, yet predicting these losses is difficult because they depend on disease severity, weather, pathogen aggressiveness, and crop compensation, making accurate disease‑management thresholds essential for integrated pest management. The study reviews and analyzes literature on a representative wheat host‑pathogen system to identify knowledge gaps and research areas for better yield‑loss assessment and economic‑threshold‑based management. The authors review crop‑loss studies, highlighting their resource demands and the challenge of multiple pathogens, and analyze literature on disease epidemiology, crop physiology, yield development, damage mechanisms, and management practices to better understand the disease‑crop loss relationship.

Abstract

The estimated potential yield losses caused by plant pathogens is up to 16% globally and most research in plant pathology aims to reduce yield loss in our crops directly or indirectly. Yield losses caused by a certain disease depend not only on disease severity, but also on the weather factors, the pathogen's aggressiveness, and the ability of the crop to compensate for reduced photosynthetic area. The yield loss-disease relationship in a certain host-pathogen system might therefore change from year to year, making predictions for yield loss very difficult at the regional or even at the farmer's level. However, estimating yield losses is essential to determine disease management thresholds at which acute control measures such as fungicide applications, or strategic measures such as crop rotation or use of resistant cultivars are economically and environmentally sensible. Legislation in many countries enforces implementation of integrated pest management (IPM), based on economic thresholds at which the costs due to a disease justify the costs for its management. Without a better understanding of the relationship between disease epidemiology and yield loss, we remain insufficiently equipped to design adequate IPM strategies that will be widely adapted in agriculture. Crop loss studies are resource demanding and difficult to interpret for one particular disease, as crops are usually not invaded by only one pest or pathogen at a time. Combining our knowledge on disease epidemiology, crop physiology, yield development, damage mechanisms involved, and the effect of management practices can help us to increase our understanding of the disease-crop loss relationship. The main aim of this paper is to review and analyze the literature on a representative host-pathogen relationship in an important staple food crop to identify knowledge gaps and research areas to better assess yield loss and design management strategies based on economic thresholds.