314 



PLANT DISEASES 



which when magnified is seen to consist of pale olive 

 upright conidiophores, each bearing at its apex or tip a 

 large spindle-shaped, many-septate, pale olive conidium. 



In some cases the blotches become much elongated, and 

 do not run into each other. The mycelium spreads in the 



Fig. 84. — Helminthosporiitin turcicum. i, portion 

 of an Indian corn leaf, diseased ; 2, a tuft of conidio- 

 phores bearing two conidia, X 300. 



tissue, which finally becomes dry and brittle. The appear- 

 ance of the fruiting condition on the surface of the leaf 

 depends much on climatic conditions; if uninterruptedly 

 warm and moist, the leaves often become brittle, and fall 

 to the ground in fragments before the conidia are formed ; 

 these however do develop on the pieces lying on the ground. 



