i;o DISEASES OF CULTIVATED PLANTS 



Perithecia sunk in the substance of the leaf; asci 60 X 

 10-12 p, without paraphyses ; spores 12-16 x 5-6 /x. 



Bernard, Ch., Bull. Depot Agric. Ind. Neerland, No. 6 

 (1907). 



TRICHOSPHAERIA (FUCKEL) 



Perithecia subglobose, superficial, sparsely or densely hairy, 

 sometimes seated on a byssus ; ascia oblong or cylindrical, 

 8-spored; spores hyaline, continuous, elongated, sometimes 

 appendiculate. 



Sugar-cane disease, caused by Trichosphaeria socchati 

 (Massee), a wound fungus that gains an entrance into the cane 

 through broken ends of lateral shoots, dead leaf-bases, etc., 

 but more especially through holes made by the moth-borer 

 (Diatraea saccharalis, Fabr.) or the shot-borer (Xyleborus per- 

 forans, Wall.). The mycelium first traverses the vascular 

 bundles, which become bright red, a marked symptom of the 

 presence of the fungus in an early stage of disease. Two 

 conidial forms are produced, which form black streaks on the 

 surface of the cane, the conidia protruding like black, curly 

 hairs from the surface. Finally an ascigerous form appeared 

 on some diseased material at Kew, but this has not been met 

 with elsewhere. The disease was at one time very severe in 

 the West Indies, and has also been recorded from Mauritius, 

 India, Java, and Queensland. 



Ascigerous stage. Perithecia broadly ovate, blackish- 

 brown, sparsely clothed with long, dark, rigid hairs ; asci 

 cylindrical ; spores 8, oblique i-seriate, continuous, hyaline, 

 elliptic-oblong, 8-9 X 4 /*, paraphyses absent. 



Only met with on thoroughly decayed, very old canes. 



Melanconium stage ; oozing out of the surface of dying 

 canes in the form of black, hair-like, curled tendrils ; conidia 

 produced in conceptacles in a stroma formed under the 

 epidermis, i-septate, pale brown, cylindrical, 14-15 X 3*5-4 /* 



Macroconidia ; forming an intensely black, velvety layer, 

 lining cracks and cavities in decaying canes, conidia in chains 

 originating within the ruptured apex of a hypha, terminal 

 conidium globose, remainder barrel-shaped, blackish-brown, 

 1 8-20 X 12 //,. 



Microconidia ; similar in origin and structure to macro- 

 conidia, but smaller, growing on the diseased surface of the 

 cane, forming black, velvety patches. 



