[4][5] Older plant leaves have white striations that eventually turn silvery gray, which is evidence of the pathogen's impending sporulation.

[citation needed] Urocystis agropyri produces teliospores, which may be wind dispersed or distributed through soils via machinery or animals.

In soil, a dikaryotic teliospore germinates, meiosis occurs, then mitosis, and this gives rise to up to four basidiospores, each containing a single nucleus.

[6][7] Some hyphal cells give rise to smut sori, bearing teliospores, which emerge through the leaf tissue for wind dispersal.

[3] Flag smut has been reported in Australia, the United States, Canada, South Africa, China, Japan, India, Egypt, and Pakistan.

[4][6] Cultivation practices that leave plant debris on soil surfaces enhances U. agropyri's success, as does sowing wheat in winter rather than spring.

[citation needed] Generally, strategies to prevent flag smut include use of disease resistant cultivars, chemical seed treatments, and crop rotation to reduce amount of inocula present.

[3] In addition to seed treatments, application of systemic fungicides early in the growing season and at low doses is effective at controlling the disease.

[4][6] Australia experienced the greatest loss known early in the 20th century due to susceptibility of popular wheat varieties and lack of fungicides at the time.

[3] The occurrence of the disease in the United States was limited to the Pacific Northwest and was the result of the introduction of susceptible cultivars in the mid-twentieth century.

[4] Between 1955 and 1971, flag smut damage and distribution increased in the Pacific Northwest of the United States when the use of several susceptible wheat cultivars was coupled with deep seeding in early autumn planting.

[3] Through use of resistant cultivars, the Pacific Northwest's flag smut issue no longer poses a significant threat to yields.