SUMMARY AND RECOMMENDATIONS. 29 



The disease is communicated in a number of ways: (1) By the 

 water of irrigation ; (2) by cuttings from diseased plants; (3) prob- 

 ably by the pruning knife; and (4) by insects. 



As a protection against frost injuries, cuttings or young vines 

 should be planted deeply in the soil, especially in arid regions, allow- 

 ing only one bud to project above the surface of the ground. 



Cuttings and young vines should be secured from healthy surround- 

 ings. It is better to use vines grown under one's personal supervision 

 than to purchase from a vineyard or nursery known to be infected 

 with the disease. 



Grapevines should be pruned in the spring either before or just 

 after the period of sap flow, the time varying with the locality. They 

 should be protected in winter from freezing where necessary, and the 

 protective covering should not be removed until the danger of injury 

 is passed, because the wounds produced by late frosts afford a means 

 of entrance to the organisms causing the disease. 



Finally, in a new vineyard resistant vines should be planted if 

 possible. If it is necessary to grow nonresistant vines they should 

 be grafted on stocks that are resistant. All diseased vines should 

 be burned as soon as they are discovered and replaced with healthy 

 resistant vines. 



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