436 



DISEASES OF CULTIVATED PLANTS 



spots are more or less circular, and surrounded by a well- 

 developed, blackish border, hence the American name of 

 bird's-eye rot. When the fungus produces fruit on the 

 diseased spots they are greyish in colour, due to the masses 

 of conidia present. There are generally several diseased 





\ 



FlG. 135. G loeospori um ampelophagiiin. i, appearance of 

 disease on stem, leaves, and tendrils of vine ; 2, diseased grapes ; 

 3, section of pustule of fungus on young grape ; 4, conidia. 

 Figs, i and 2 natural size ; remainder mag. 



spots scattered over the fruit. When one grape in a bunch is 

 infected, the disease spreads rapidly until every grape is 

 attacked, the spores being washed by rain from one fruit to 

 another. Diseased fruit often becomes contorted and much 

 cracked, exposing the pips, and finally shrinks and becomes 

 mummified, still remaining hanging on the vine. 



