Uromyces

Uromyces is a genus of rust fungi in the order Pucciniales. It comprises numerous species that are obligate plant pathogens, causing rust diseases on a broad range of host plants, particularly legumes, grasses, and ornamentals.

Species in Uromyces are biotrophic parasites that infect living plant tissue and typically produce the characteristic rust pustules seen on leaves and stems. During the growing season they form uredinia that release urediniospores, enabling repeated cycles of infection. Many species also form telia bearing teliospores for overwintering, and some have a sexual stage with basidiospores. Life cycles vary among species; some are autoecious (on a single host), while others are heteroecious (requiring alternate hosts).

Symptoms include yellow to orange or brown lesions and powdery rust pustules, which can reduce photosynthesis and vigor and lead to yield losses in affected crops. Uromyces species are distributed worldwide, with greatest impact in temperate and subtropical regions where leaf wetness and favorable temperatures promote infection. Identification relies on host association and microscopy of spore morphology, often in conjunction with the pattern and location of pustules on the plant.

Management centers on preventing infection and limiting spread, including the use of resistant cultivars, crop rotation and sanitation, and the judicious application of fungicides in high-value crops. As obligate biotrophs, Uromyces diseases are typically managed through preventive cultural practices and protective plant protection measures rather than curative treatment.