204 THE FUNGI WHICH CAUSE PLANT DISEASE 



Germ tubes from ascospores or conidia enter the cortex and 

 develop a rich mycelimn in the sieve tubes and soft host. This 

 advances most rapidly during the dormant period of the bast. 



White or yellow stromata the size of a pin- 

 head appear and bear numerous conidia. Later 

 come the red perithecia whose ascospores ripen 

 in winter or spring. 

 N. ribis (Tode) Rab. 

 Fig. 144.— n. ipo- Cespitose, Stroma compact; perithecia sub- 



of perithecia. globose, smooth ; ostiole papillate ; asci subclavate, 



After HaUted. 90-100 x 15; spores elongate or fusoid, hyaline, 

 1-septate, 18-20 x 5-6 mm. On currant. 



N. ipomoese Hals. 



Perithecia clustered, ovate, roughened, red; asci cylindric- 

 clavate; spores elliptic; conidial phase (Fusarium) appearing as a 

 white mold-like covering of the host; conidia several-celled, falcate. 



Halsted ^* inoculated sterilized egg-plant stems with the Nectria 

 spores and the Fusarium form developed, followed by the asci- 

 gerous stage. Ascospores in hanging drop were also seen to give 

 rise to the Fusarial stage. The Nectrias found upon egg-plant 

 and sweet potato, morphologically alike, were proved by cross 

 inoculations to be identical. 



N. rousseUiana Tul. and N. pandani Tul. are parasitic on Buxus 

 and Pandanus respectively,*' the former with the conidial stage. 

 Volutella buxi. 



N. solani Ren. & Bert, is said by Massee to be the ascigerous 

 form of Fusarium solani.** 



Perithecia crowded on a stroma, minute, conic-globose, smooth, 

 blood-red; asci clavate; spores hyaline, 8-9 x 

 5 n; paraphyses slender, tips strongly clavate. 



Conidia (=Fusariiun solani) hyaline, 3 to 

 5-septate, fusiform, 15-40 x 5-^ fi, but very 

 variable, borne on erect, simple or branched Fig. 145.— n. ipo- 

 COnidiophores. moea, the Fusa- 



•KT a • 1 rw- num stage. After 



a. coneicola Zimm. is on cacao and vanilla; Halsted. 

 N. bainii Mas. N. amerunensis A. & Str. and N. diversispora 

 Petch. are reported parasitic on cacao ^^ pods. The three latter 

 names are probably synonyms of the first. 



