Screening Fungicides for Controlling Wheat Crown Rot Caused by Fusarium pseudograminearum across Hebei Province in China

Wheat Fusarium crown rot (FCR) is caused predominantly by Fusarium pseudograminearum across most wheat-producing countries; this fungal disease needs a specific combination of fungicides to control it. In this research, the efficacy of four fungicides against F. pseudograminearum is tested using in vitro assays. Our results showed that fludioxonil had an EC50 of 0.0447 mg/L, followed by difenoconazole (0.3845 mg/L) and tebuconazole (0.4919 mg/L). Azoxystrobin (2.6019 mg/L) was also effective. Commercially available fungicides with the first three ingredients as active ingredients were further tested for the control of FCR. Cruiser Plus and Celest presented higher efficacies in an environmentally controlled pot assay. Further testing in the field achieved a higher level of control by Cruiser Plus than Celest at the seedling (72.34% vs. 62.55%) and adult (56.76% vs. 47.78%) stages in a field plot experiment. When tested in naturally infected wheat fields in Linzhang, Hebei Province, applications of the two fungicides resulted in relative control efficacies of 45.17% and 38.57%, respectively, and grain yields were increased by dressing with Cruiser Plus (8.7%) and with Celest (5.3%). Furthermore, seed dressing combined with additional spraying in early spring resulted in significantly better control of FCR and higher grain yield than seed dressing treatment alone (10.4% and 7.4%, respectively). Similar results were obtained when tested in Xian County, Hebei Province, with a disease control efficacy of 40.36-59.91% and a yield increase of 4.2-7.5%. Integrated measures of dressing (Cruiser Plus and Celest) combined with spraying (Horizon) showed higher control efficacy to FCR.