120 



DISEASES OF CULTIVATED PLANTS 



liberated and dispersed throughout the house. Tendrils and 

 parts of the flower behave in a similar manner when attacked. 



FIG. 26. Plasmopara viticola. i, under surface of a vine 

 leaf showing white patches of mildew ; 2, group of conidiospores 

 bearing numerous conidia ; 3, three conidia more highly mag. ; 

 4, conidia containing zoospores, in b, two zoospores have 

 escaped from the conidium ; 5, mature oospore or resting-spore ; 

 6, an oospore germinating and producing a conidiophore (after 

 Prillieux) ; 7, autumnal form of conidiophore bearing a few 

 large conidia (after Prillieux). Fig. i reduced, remainder highly 

 mag. 



Oospores are produced in abundance in the dying portions of 

 the plant. 



When a plant is attacked, the fruit, even if not directly 

 infected, suffers in consequence, and rarely matures, owing to 



