Watch for white smut on Gaillardia plants

Begin scouting now for easily recognizable symptoms of white smut in landscape beds and nurseries.

White smut is a fairly common problem on Gaillardia, also known as blanket flower. Young lesions create faint, whitish spots. Spots become slightly larger and more obvious over time. Eventually, the spots turn brown in the center and may be bordered by whitish-colored halos.

white smut
White smut on Gaillardia.

white smut
Close-up of spots on Gaillardia plant caused by white smut.

This disease is caused by several related fungal pathogens in the genus Entyloma. Spores are produced on the surface of the lesions. Additionally, a resting spore is produced later in the season inside the diseased foliar tissue.

Plants in nursery production, with close spacing and overhead irrigation, tend to be more severely diseased than plants in the landscape. However, from personal experience, I know that plants in landscape beds without overhead irrigation can also be heavily affected.

Where feasible, diseased foliage should be removed and destroyed. Plants in greenhouses may need fungicide applications for good disease control. Landscape plantings benefit greatly from having the foliage completely removed at the end of the season. The disease has been seen with increasing frequency in the past few years. There may be some variation in cultivar susceptibility; disease has been documented on the cultivars ‘Goblin,’ ‘Baby Cole’ and ‘Fanfare.’

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