Stability and Efficacy of Fungicides Registered for Organic and Commercial Wheat Production in Hungary Against Fusarium Head Blight—A Comprehensive Methodology to Enhance Food Safety

Fusarium head blight (FHB) is one of the most significant diseases in wheat globally, affecting about 200 million tons of grain per year through mycotoxin contamination. Besides yield losses, mycotoxin contamination is a major concern. FHB resistance in wheat is partial and polygenic, and since the efficacy of plant protection measures is generally weak-to-moderate, an integrated approach is needed for successful control. We evaluated a more comprehensive methodology for improved protection; in this two-year study, five registered organic products and six conventional products were compared under artificial and natural infection conditions. The disease index (DI), <i>Fusarium</i>-damaged kernels (FDKs) and deoxynivalenol (DON) contamination were evaluated. The stability of the fungicides was also evaluated based on 10 epidemic conditions. The organic fungicides showed much lower efficacy than the conventional ones, although significant reductions in symptoms and DON contamination were observed. In each group, significant variability was detected. The best fungicides for DON contamination showed the lowest variance (highest stability) between 10 and 20 (Verben, Prosaro, Ascra Xpro). The organic fungicides were much less stable; the least stable showed a variance of 141 (Fusarium control: 264). The best organic fungicide was the Bordeaux mixture supported by sulfur addition (variance: 54). The DI and FDK values presented very similar trends. For the more resistant cultivar GK Pilis, the combined DON reduction exceeded 90% for all fungicides. For the most susceptible cultivar, GK Békés, the values were between 30 and 83%, respectively. High resistance to FHB and toxin contamination is the key to controlling FHB in both organic and conventional production. For efficient fungicide control, stable resistance to disease and toxin accumulation are equally required. Principal component analysis (PCA) verified the importance of considering all traits to identify the fungicidal "fingerprint" and demonstrated the differences between fungicides regardless of their organic or conventional nature. PC response differs for traits and fungicides, supporting the complex evaluation of plant and fungicide behavior. Knowledge of resistance levels, in addition to improving mycotoxin control, aids in disease forecasting and epidemic management. The results are applicable to both organic and conventional production systems. Due to the variability in resistance and fungicidal effects, there is an opportunity to improve food safety in both organic and conventional wheat production.