TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



77 



from healthy cuttings and showing all of the characteristics of a gener- 

 ally distributed parasitic malady. 



(3) There are striking differences, in the susceptibility to this disease, 

 of different varieties and species of grapes, although in the heat of a 

 first epidemic many varieties will die more rapidly or more generally 

 than after the height of the epidemic has passed. 



We gather from these general observations certain guiding facts: 

 (a) Vineyards in unaffected districts should be carefully guarded 

 against all weakening influences, as a radical change of moisture con- 

 ditions, for the prevention of disease is always better than cure; 

 (h) When the disease obtains a foothold its presence should not be 

 ignored, but its effects should be carefully studied with a view of deter- 

 mining the comparative resistance of the varieties and species of grapes 

 already growing in the district; (c) In replanting, only the hardier 

 types should be selected, and in case these vines are unsatisfactory in 

 fruiting qualities the hardiest known root should be planted and top- 

 grafted with the most resistant variety producing the type of fruit 

 required. 



At present the vine most resistant to the California vine disease and 

 which is believed by most growers to be of Vitis vinifera origin, although 

 this is still an open question, is the Lenoir. Upon its own roots this 

 vine is almost completely resistant, and this is especially true of vines 

 set after the heat of the first epidemic has passed. The raisin grape 

 showing the greatest hardiness is the Malaga. One of the hardiest 

 table grapes is the Tokay. Some of the more resistant wine grapes are 

 the Feher Zagos, Black Malvoisie, Grenache, and Herbemont. 



The Lenoir vine has shown such great resistance to the disease that 

 experiments were inaugurated by the United States Department of 

 Agriculture to ascertain its value as a root upon which to graft the 

 more susceptible varieties. Nearly four hundred acres of Lenoir vines 

 have been planted and grafted to other varieties during the past seven 

 or eight years, the work being done by leading viticulturists. The 

 evidence to date is that the Lenoir root greatly aids a more susceptible 

 top variety in resisting the disease, and in case the top graft is of a 

 somewhat hardy variety the combined resistance has thus far proven 

 satisfactory from the commercial standpoint. This work is still in 

 progress, but it is believed that the results already obtained warrant 

 the presentation of these facts to the growers. 



A concluding word relative to the nature of resistance may not be 

 inappropriate. Vines which are resistant to phylloxera are not of 

 necessity those which are free from that insect, but they are vines 

 sufficiently hardy to withstand its attacks and still permit of successful 

 viticulture. This is equally true respecting resistance of root and top 

 in the presence of the California vine disease. The disease affects even 



