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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #35401
Title: FOLIAR BLIGHT OF BIGFLOWER VETCH CAUSED BY ASCOCHYTA FABAE F. SP. VICIA

Author
item LEATH K T - 1902-05-00
item DEGREGORIO R E - UNIV OF CONNECTICUT
item ASHLEY R A - UNIV OF CONNECTICUT

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: Bigflower vetch is a winter annual legume that is used in pastures and specialized crop rotations. Little is known about its susceptibility to disease. A severe foliar disease developed on bigflower vetch while being grown in Connecticut. All above-ground plant organs were attacked. A fungus was isolated from diseased plant tissues, which was identified as Ascochyta fabae Speg. This was the first report of this fungus attacking bigflower vetch. Fifty-nine species of legumes were inoculated with the fungus, but only bigflower vetch was susceptible to attack. Because the fungus has a high pathogenic specificity, growing bigflower vetch in rotation with other legumes should not be problematic. This fungus, however, has the potential to impair seriously the performance of bigflower vetch in the northeastern U.S. and probably in other regions as well.

Technical Abstract: Bigflower vetch (BFV) (Vicia grandifolia W. Koch var. kitaibeliana) is a winter annual legume used in pastures and as a winter cover crop in specialized situations. During evaluation in a sweet corn rotation in Connecticut, BFV became severely diseased by a foliar blight. The fungus, Ascochyta fabae Speg. was identified as the causal agent, and leaf spots plus necrosis of stems, petioles and tendrils were produced with artificia inoculations. The fungus caused only minor leaf flecking on four test legume species and no symptoms on the other 54 species. Only BFV was highly susceptible. The very narrow pathogenic specificity of the BFV isolate indicated that growing BFV in rotation with other legumes would not likely be problematic. This strain of A. fabae has the potential, however, to greatly impair the productivity to BFV in the northern U.S. and probably elsewhere. Ascochyta fabae Speg. f. sp. vicia is the name proposed for the especialized form of the fungus pathogenic to BFV.