pnut pnut Peanut Science 0095-3679 0095-3679 American Peanut Research and Education Society 10.3146/i0095-3679-13-2-10 Articles Importance of Seed Transmission in The Spread of Cylindrocladium Crotalariae1 D. Morris Porter and R. Walton Mozingo 2 Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Tidewater Research Center, Suffolk, VA; and Associate Professor, Department of Agronomy, Virginia Polytechnic Institute and State University, Tidewater Research Center, Suffolk, VA, respectively

1Cooperative investigation by Agricultural Research Service, U.S. Department of Agriculture, Suffolk, VA 23437, and Virginia Polytechnic Institute and State University, Blacksburg, VA 240461.

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 7 1986 13 2 80 82 4 10 1986 American Peanut Research and Education Society 1986 American Peanut Research and Education Society Abstract

Cylindrocladium crotalariae, which causes Cylindrocladium black rot (CBR) of peanut (Arachis hypogaea), can be isolated at a low frequency from nondamaged peanut seed (seed size ≥6.4 × 25.4 mm slotted screen) not treated with a seed protectant fungicide. Peanut seed obtained from peanut fields in Suffolk, VA, and Martin County, NC, where CBR was severe in 1985 were infected at a frequency of 1.5% and 1.4%, respectively. Cylindrocladium crotalariae was isolated at twice the frequency from pieces of seed than from whole seed. However, C. crotalariae was not isolated from seed treated for 2 weeks with a seed protectant (DCNA + captan). The fungus was not isolated from seed devoid of testae or seed embryos, but was isolated from seed testae at a frequency of 0.4%. Discolored seed (≥6.4 × 25.4 mm) were infected at a frequency of 7.9%, but following seed treatment, the isolation frequency dropped to zero. Discolored seed measuring < 6.4 × 25.4 mm were infected with C. crotalariae at a frequency often exceeding 10%.

 Key Words Peanut; , seed contaminant; , Arachis hypogaea; , seed protectant