DISEASES OF THE GRAPE. 



83 



which they have ravaged and deserted, and which is decaying; 

 d, d, d, lice on large roots; e, the female pupa, seen from above; 

 f, female pupa, seen from below; g, winged female, dorsal view; 

 h, the same, ventral view; i, antenna of -the winged insect. 



While the insect is almost always found upon our native vines 

 in large numbers, especially the root form, their vigor of growth 

 seems to overcome its attack, and no Dermanent injury results. 

 No remedy has been successfully applied. 



DISEASES. Varieties that have originated from the European 

 grape, wholly or in part, are often subject to the mildew, as are 

 also native varieties under certain conditions. It is a fungus 

 parasite that grows in the tissue of the leaf, destroying it by 

 penetrating the cell wall and feeding upon the food prepared for 

 the nourishment of the vine. When mature, the fruit of the 

 mildew fungi is borne upon stalks that come out of the breathing 

 pores of the leaves, and appear in such numbers as to give the 

 leaf a mealy appearance, whence the name, meal dew, or mil- 

 dew. It makes its appearance during wet weather, when the 

 vine is in an unhealthy condition from 

 any cause. It is doubtful if this fun- 

 gus will grow upon perfectly healthy 

 tissue. 



Remedy. Good cultivation, plenty 

 of sunlight and a liberal supply of 

 potash and bone is the -best remedy 

 that can be applied. 



GRAPE-BERRY MOTH (Endermis bo- 

 tiana) is destructive only when abun- 

 dant. Fig. 68 shows the perfect 

 insect at a, c the discolored spot 

 where the worm has entered the fruit, 

 b the worm, and d the berry it has 

 deserted. There is no practical rem- 

 edy, but burning the fallen leaves to 

 destroy the chrysalides they harbor is recommended. 



