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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #35417
Title: RESPONSES OF RED CLOVER CULTIVARS TO STEMPHYLIUM LEAF SPOT

Author
item Berg, Clyde
item LEATH, K - 1902-05-00

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Stemphylium leaf spot is a serious leaf fungus on red clover in the northeastern USA and Canada. Genetic resistance is the only practical method to control this disease. Varieties were tested in the greenhouse to determine if there were differences among varieties, if resistant plants could be identified within varieties, and to determine the detrimental effect of Stemphylium leaf spot on forage yield. We found only small differences among varieties for disease resistance, a few plants in each variety were resistant, and forage yield was reduced about 30% by Stemphylium infection.

Technical Abstract: Stemphylium leaf spot [Stemphylium sarciniforme (Cav.) Wiltsh.] of red clover (Trifolium pratense L.) occurs at high severity levels in the northeastern USA and Canada during most seasons. Red clover was grown in the greenhouse and inoculated with S. sarciniforme to determine the levels of resistance within and among cultivars, and dry matter yield losses caused by this disease. Significant differences in disease severity score occurred among 15 cultivars, but even the most resistant cultivars were scored as susceptible. Within each cultivar, 1 to 10% of the plants were scored as resistant phenotypes. When approximately 30% of leaf area was affected by Stemphylium leaf spot, forage yield was reduced up to 30%. Uninoculated regrowth from previously inoculated plants was also reduced up to 30%.