51 G Report of the Department of Horticulture of the 



fungi and insects. Pests there were in the vineyard in abund- 

 ance, as the tales of tribulation told in the annual reports have 

 shown, but the knowledge gained by the experimenters as to the 

 comparative immmiity of stocks and varieties is but a thing of 

 shreds and patches and is hardly worth discussion. 



Toward fungus diseases, chiefly the downy and powdery mildews, 

 more particularly the latter though both of them were present 

 nearly every season, the varieties, as would be expected, behaved 

 on the grafted vines just as they did on their own roots. It has 

 been well demonstrated in California and France that the stocks 

 in this experiment, as well as all of the varieties on their own roots, 

 behave differently under the attacks of phylloxera but this pest was 

 at no time plentiful enough to fui'nish data for conclusions. The 

 grape-root worm, Fidia viticida, has been ravaging the vineyards 

 of the Chautauqua region for several years. The greatest disap- 

 pointment in the work with this vineyard is that a detailed state- 

 ment cannot be made of the differences between stocks or varieties 

 on their own roots as to the attacks of lidia. There are differences 

 and they are likely to prove as important with the fidia as with 

 phylloxera, but this experiment has not furnished sufficient data 

 to substantiate in detail the very general statement that this insect 

 has its likes and dislikes among the stocks and varieties under trial. 



How does grafting cause its effects? — The effects of grafting 

 are so similar to those of annular incisions or injuries of any kind 

 — greater productiveness, larger bunches and fruits, and earlier 

 ripening — that one might well believe the mode of action to be 

 the same. There is this difference, however — ringing acts but 

 temporarily, only as long as the flow of sap through the cambium 

 is interrupted, while the effects of grafting are permanent. The 

 mechanical effect of grafting may be the same as that of ringing 

 for the first year, or possibly two, but no longer. The similarity 

 between grafting and ringing ceases as soon as stock and cion in 

 the graft are completely united. 



This experiment furnishes no facts as to how grafting causes its 

 effects. It would seem, however, that it is not the operation itself 



