Clover (Trifolium spp.)-Common Leaf Spot

Latest revision: 
March 2024

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Cause Pseudopeziza trifolii, a fungus. It attacks red clover primarily but also white and crimson species. Leaf spot occurs throughout the growing season but is most severe in fall. Long-term infections may reduce plant vigor and contribute to winter injury. The fungus survives in plant residue. No resistant varieties are known; tetraploid varieties are more susceptible than diploids.

Symptoms Leaf spots are dark brown to black with irregular or fringed edges. Spots are on both leaf surfaces. Fruiting structures (raised disks) appear on the upper surface and ooze an amber liquid under moist conditions. Lesions on petioles are rare.

Cultural control

  • Cut early to minimize leaf loss and to reduce inoculum.

Chemical control Foliar fungicides effectively reduce disease severity and may be considered for clover seed crops.

  • Quadris Flowable (Group 11) at 6 to 15.5 fl oz/A. Do not apply more than 15.5 fl oz/A per cutting. Preharvest interval is 14 days for grazing or harvest for forage and hay. 4-hr reentry.