Chapter VI 

 Protecting the Vineyard from Insects and Fungi 



If I should name, describe and prescribe against all the insect and fungus parasites of the 

 grape, it would require a considerable book. Fortunately among such a host, there are only five 

 insects that seriously damage grapes in the United States, so that they require combatting to 

 secure success, whenever they attack in great numbers, and likewise only four or five serious fungi 

 to fight. In combatting all these, prevention is the only remedy, for cure is impossible after the 

 damage has been inflicted. In other words we must ward off, or kill the insects and fungi that do 

 serious damage, before they do their eating of the tissues of the vine. 



Insects That Must be Fought to Prevent Serious Damage 



The Root Louse. (Phylloxera vastatrix-} 



The Phylloxera is a minute aphis, scarcely visible to the unaided eye. It has several different 

 forms, winged and unwinged, male and female. The winged form issues from the ground about 

 midsummer and lays eggs upon the under side of young leaves of the grape. The eggs soon hatch 

 into invisible larvae, and their irritation causes a small wart or gall to form on the under side of 

 the leaf. These young aphises, each in a gall of its own making, soon lay eggs which hatch in 

 the galls, are male and female, which pair and finally emerge from the galls^on under side of leaf. 

 All are wingless that continue to breed on the leaves. The females again cause galls and lay eggs 

 and so continue as long as young leaves can be found or till cool nights of fall. In fall the females 

 lay larger, hardy eggs in the crevices of the bark, and other places, to winter over and begin 

 generation on the leaves next season. When young leaves cannot be found to work upon the 

 insects go into the soil and attack the tender rootlets. It is here where their chief harm is done. 

 In puncturing the rootlets of very tender rooted kinds, such as Vinifera, they introduce into the 

 juices of the young cells a species of bacterium (discovered by Millardet), that, similar to the pear- 

 blight (Bacillus amyilovorus), introduced into the flowers or growing tips by insects, destroys 

 the tree, unless cut out and burned ; or the malarial bacterium, introduced into the human by a 

 mosquito, causes death unless checked. 



The underground root-louse continues to multiply along the roots for several generations, 

 and may not produce any winged forms for several years, unless favorable seasons occur, when a 

 few of the females, in midsummer, acquire wings, and leave the ground to lay their eggs on the 

 young leaves, to breed there thru summer, as already described. 



As the insect is a native in all parts of the United Ctites east of the Rockies, the native 

 vines there have become immune to the influences of the bacterium that the louse introduces, 

 while species of grapes not native in regions where the louse is native, especially the soft-rooted 

 Vinifera, are not immune. 



This is the reason that Vinifera grows well in the milder regions east of the Rockies, when 

 grafted on native American grape roots, but perishes in a few years if on its own roots. 



By so grafting the more robust of the foreign grapes in most parts of the South and spraying 

 carefully with Bordeaux Mixture, these kinds can be successfully and profitably grown there 

 almost as well as in California and France, especially so in Southwest Texas, west of the 98th 

 meridian. 



Only the Old World grapes (V. mnifera) must be protected against this, as American grapes 

 that is, varieties sprung from species native in the United States east of the Rocky Mountains, 

 are resistant. 



There has been only one remedy found that is fairly satisfactory, and that is, 



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