Application of Difenoconazole and Trichoderma Broth Combination for Synergistic Control of Corn Leaf Blight and Stalk Rot in Straw-Returned Fields in Liaoning Province, China

Maize production in Fuxin City, Liaoning Province, China, is threatened by northern corn leaf blight (NCLB) and Fusarium stalk rot, with straw return under conservation tillage exacerbating the NCLB severity by 20% in local fields. This study evaluated the efficacy of combining difenoconazole, a commonly used fungicide, with a Trichoderma bioagent for disease control in straw-incorporated soils. Field trials in Fuxin showed that applying 300 g/ha difenoconazole with 1.5 L/ha Trichoderma fermentate achieved superior results: a 72.4% reduction in the NCLB disease index and a stalk rot incidence of only 0.61%. These outcomes significantly outperformed single-component treatments like difenoconazole alone (56.2% NCLB suppression) or other fungicides (e.g., carbendazim, triadimefon). The combined treatment also outperformed the single treatments with biocontrol agent (67.1% NCLB inhibition). The results highlight the synergistic potential of integrating chemical and biological agents to manage residue-borne diseases, offering a practical strategy for sustainable disease control in conservation agriculture systems with straw return in Liaoning, China.