326 PLANT DISEASES 



Diseased bulbs should be collected and burned to prevent 

 the dispersion of conidia. 



Mystrosporium alliorum, Berk. This species sometimes 

 forms dark patches on onion bulbs. 



Mystrosporium abrodens, Neumann. Said to be destruc- 

 tive to the wheat crop in some districts in France. Dark 

 patches are formed in the leaves and nodes, the latter 

 becoming weak. The plant bends over. The ears are 

 imperfectly developed. 



Neumann, Soc. Biol. Toulouse, 1892. 



THREAD BLIGHT OP TEA PLANT 



(Stilbum nanum, Massee.) 



Indian tea-planters have known this most destructive 

 fungus for at least the last thirty years. The name ' thread 

 blight' is given on account of the very thin strands or 

 films of white mycelium that are firmly attached to the 

 branches and under surface of the leaves of the tea plant. 

 The mycelium also runs under the surface of the branches, 

 living in the tissues of the bark, and coming to the surface 

 here and there to spread over the outside of leaves and 

 twigs. 



The fruit only appears to be formed on very old, rotten 

 branches that have fallen to the ground and become 

 decayed, and resembles pins in miniature a very slender 

 stem and a round head, the whole not half a line high. 

 Repeated observation proves the fruit to be very rare, 

 and infection from spores may be left out of consideration, 

 except in the case of reclaimed ground, where the trees 

 have been neglected for some time. 



