Phylum:Ascomycota >> Class: Ascomycetes >>  Order: Pleosporales 
 BCRC Number NO BCRC Number!  
 Scientific Name: Leptosphaerulina crassiasca

Basionym: Pleospora crassiasca Sechet., Oléagineux 10: 414. 1955.

Leptosphaerulina crassiasca (Sechet) C. R. Jackson & D. K. Bell., Oléagineux 23: 387-388. 1968.

 Description: On V8: Colony hyaline when young, barely visible, hyphae appressed to agar surface, becoming black with development of pseudothecia, sectors of colony sometimes becoming covered with a flat, felt-like layer of white aerial hyphae. Colony diameter from single spores 3-5 mm after 2 days and 16-18 mm after 3 days. Vegetative hyphae hyaline, thin-walled, 2-8 mm wide; fertile hyphae 8-18 mm in width, thicker walled, usually septate at shorter intervals. Pseudothecia with mature ascospores present after 3 days. Pseudothecia solitary and scattered, subglobose to broadly oval or obpyiform, (90)-135-(180) × (82)-127-(180) mm, lightly pigmented with translucent walls when young. Pseudothecial wall 8-10 mm thick; wall cells angular to oblong with slightly thickened walls, dark brown when mature. Ostiolar neck papillate to elongate, composed of subhyaline cells. Paraphyses lacking, but remnants of centrum tissue may occur between asci. Asci clavate when young, becoming saccate or ovoid to broadly obclavate, (58)-71-(84) × (30)-42-(52) mm, 8-spored, bitunicate (fissitunicate). Ascospores arranged in an irregular cluster in ascus, usually muriform, but some phragmosporous, containing 3-5 transverse and 0-2 longitudinal septa, oblong to ellipsoid, often widest above the middle, rounded at the top and tapering toward the bottom, slightly constricted at the septa, (28)-33-(38) × (10)-15-(20) mm, surrounded by a thin gelatinous sheath, hyaline when mature, becoming light brown upon release.

On Arachis hypogaea. Taiwan: K. T. Huang (ATCC 13446), Dec., 1955 (as L. arachidicola) (GAM 12765).

 Habitat: Foliicolous. Parasite on the leaf of peanut.

Cosmopolitism; temperate and tropical area, such as: Florida and Georgia of the United States of America and Yunlin of Taiwan.


Wu, ML and Hanlin, RT. 1991; Wu, ML. 1996.


M. L. Wu

 Note: Leptosphaerulina crassiasca is the causal agent of pepper spot and leaf scorch disease of peanut. The Taiwan isolate (Leptosphaerulina arachiclicola Yen, Chen & Huang, synonym of L. crassiasca) was sent by K. T. Huang to E. S. Luttrell, who deposited it in the American Type Culture Collection. Ideally, this isolate should serve as the neotype, but its unusual growth characteristics compared to the other isolates suggest that it has changed during storage, although in the original illustrations of this isolate it appears to form a continuous colony. Therefore, a Georgia isolate has been selected to serve as the neotype for L. crassiasca.