174 DISEASES OF ECONOMIC PLANTS 



gills, white, spotted with reddish brown. It often grows in 

 large clusters near the base of the \dne. 



The disease occurs in local areas in the vineyard, and the 

 regions of affected soil enlarge irregularly. The disease may 

 further be recognized by the fact that the yield is not les- 

 sened the first year of the attack; the vine does not succumb 

 until two or three years later. The leaves are reduced in 

 size, but are normal in color. Upon the roots are found 

 dark-colored rootlike cords of mycelimii passing into and 

 among the irregularities of the bark. 



Excision and destruction of the diseased parts by fire 

 will lessen the spread of the disease. 



Bitter rot, ripe rot {Glomerella rufomaculans (Berk.) 

 Spaul. & von Schrenk). — Ripe berries only are attacked. 

 At the point of injury the color changes to reddish brown 

 and eventually the whole berry assumes this color. It 

 then decays and finally dries and shrivels. Acervuli appear 

 early upon the sunken portion, much as in the black rot, 

 except that the berry does not assume the dark hue char- 

 acteristic of the latter disease. 



Ammoniacal copper carbonate is recommended as a spray 

 as soon as the disease is noticed. 



Bitter rot, melanconiose {Melanconium fuligineum (Scrib. 

 & Viala.) Cav.). — The chief effect upon the berry 

 as it ripens consists in the appearance of a ripe rot, also 

 accompanied bj^ a very bitter taste. The fungus also 

 attacks the shoots and stem clusters. 



White rot {Coniothyrium diplodiella (Speg.) Sacc). — 

 This disease, known in America since 1887, resembles the 

 black rot except as to color. It appears upon the fruit and 

 shoots, but is not often serious. 



