Pathogen identification, biological characteristics and control agent screening of China Xinjiang white clover anthracnose

Abstract

White clover is a high-quality forage and turfgrass. In 2023, a severe anthracnose was observed on white clover in Urumqi and Altay, Xinjiang, China. The pathogen was identified as Colletotrichum destructivum based on morphology and phylogeny. Biological characteristic assays revealed that the optimum temperature for mycelial growth was 25 °C, with an optimal pH range of 7.0 – 10.0. The most favorable media for growth were PDA, PSA and CA. Soluble starch and inulin served as the optimal carbon sources, while peptone was the most effective nitrogen source. Mycelial growth occurred under three tested light conditions (24 hours of light, 24 hours of darkness, and 12 hours of light/darkness), and the lethal temperature for mycelia was 54 °C for 10 minutes. The optimal conditions for sporulation were 20 °C, pH 6.0, under continuous darkness (24 h), with PDA as the medium, lactose as the carbon source, and peptone as the nitrogen source. In vitro toxicity tests of ten fungicides against C. destructivum demonstrated that 20% Imazalil was the most effective with EC50 = 0.1347 mg/L and followed by 430 g/L Tebuconazole with EC50 = 0.2239 mg/L. This study identifies the pathogen and biological features of white clover anthracnose in Xinjiang and identifies highly effective fungicides for its management, providing a theoretical basis for field control strategies.