MONILINIA 53 



4. Monilinia Seaveri (Rehm) Honey, Am. Jour. Bot. 23: 105. 

 1936. (Plate 84.) 



Sclerotinia Seaveri Rehm, Ann. Myc. 4: 66. 1906. 

 Monilia Seaveri Reade, Ann. Myc. 6: 112. 1908. 



Conidial stage {Monilia) effused, ash-gray, epiphyllous or 

 sometimes on the twigs also, still later in minute cespitulae on 

 immature fruits, the conidia citron-shaped, simple, hyaline, 

 7-15 ji long, in long di- or trichotomously branched chains with 

 slender, fusiform disjunctors 3 or 4 ^ long; sclerotia formed in 

 mummified fruits. 



Apothecia one or two from a single mummy, about 1 cm. 

 high, long-stipitate, at first closed then expanding and becoming 

 saucer-shaped to convex and umbilicate, reaching a diameter of 

 11 mm.; stem slender, reaching a length of 5-20 mm.; asci 

 cylindric-clavate, reaching a length of 155-180 /x and a diameter 

 of 8-11 M, 8-spored; spores obliquely 1-seriate, ellipsoid, hyaline, 

 simple, 5-8 X 11-17 /x; paraphyses sparse, filiform, slightly 

 enlarged above. 



Parasitic on leaves, twigs, and fruits of Prunus serotina. 

 Type locality: Iowa City, Iowa. 



Distribution: New York to Iowa, and south to Georgia. 

 Illustrations: Phytopathology 30: 89,/. /. 

 ExsiccATi: Rehm, Ascom. 1633. 



This species has been reported as destructive to young cherry 

 seedlings by John C. Dunegan of Fayetteville, Arkansas (Phyto- 

 pathology 30: 89. 1940.), as follows: "^ Blight of Wild Cherry 

 Seedlings. — A blighting of wild cherry {Prunus serotina.) seed- 

 lings has been under observation since 1924. The disease, caused 

 by Sclerotinia Seaveri Rehm, appears each spring about the time 

 the second pair of true leaves unfolds. The first symptom is the 

 development of a brown water-soaked region near the apex of 

 the stem. This condition is accompanied by a loss of turgor 

 and the infected seedlings are readily detected by the character- 

 istic drooping of the affected portion of the stem. The infection 

 spreads from the stem into the leaves through the petiole and 

 midrib. The basal portion of the leaf turns brown and finally 

 the whole leaf is affected, assuming a bleached grey color. 

 Conidial masses frequently develop on the leaves. The fungus 

 continues to spread down the stem and, when it reaches the 

 ground line, the young plant dies. 



