WRATPINCi Al'PLK (JRAFTS AND ITS KKLATION To rR()WN-(J ALL. 19 



tory as rubber. Vhe writers strongly advise against tiie wrapping of 

 grafts with thread and su})se(iiiently waxing the grafts. 



SUGGESTION TO NURSERYMEN. 



The results obtained from the experimental plats having sliown that 

 the wrapping has materially reduced the num])er of crown-gall and other 

 types of rough trees, it will be ver}- desirable to test these results on a 

 larger scale. The grafts in these experiments were all made with the 

 greatest care, and it would seem probable that the numl)er of smooth 

 trees obtained was therefore larger than might be the case where com- 

 mercial grafts are made. The latter are usually not fitted with as much 

 care, either with respect to size of scion and root pieces or with regard 

 to an even and close union in the freshlv made graft. It is therefore 

 urged that nurserymen generally test the wrapping of their grafts 

 this winter, either with rubber or cloth, after the manner previously 

 described. 



Care should be taken in setting out grafts with different kinds of 

 wrapping to treat them in the same manner, that is — 



(1) Use the same variet}' of scion. 



(2) Use the same stock of roots. 



(3) Make the grafts at the same time. 



(4) Plant the grafts on the same- date. 



(5) Plant in the same field or at least on similar soil. 



(6) Cultivate all grafts alike. 



Where such tests are made, it is requested that the Bureau of Plant 

 Industry be informed, so that all the experiments may be compared. 



It may prove of interest to estimate the total number of smooth and 

 rough trees to the acre which would result from the use of various 

 wrappings, estimating 18,000 grafts to the acre and using as a basis the 

 percentages of such trees obtained in the tests described in these pages. 

 By smooth trees are meant trees free from crown-gall and other dis- 

 eases; by rough trees, trees affected with true crown-gall, hairv-root, 

 or manifestations of other diseases at or near the point of union. This 

 estimate has been attempted in the following table, which should ])e 

 regarded only as suggestive, however. The results are averaged from 

 five identical plats in four different States, containing about 9,000 grafts. 



Table III. — Estimate of the number of sinootli trees and rough trees which can he raised 

 on an acre of land bij using rarious methods of grafting. 



Wrapping. 



Rubber 12, 600 1, 980 14, 580 



Cloth I 12, 9G0 2, 340 15, 300 



Waxed paper I 10, 260 4, 320 14, 580 



Plain thread i 9, .540 4,320^ 13,860 



Waxed thread 9, 360 5, 220 14, 580 



Plain thread with union waxed 3,780 4,860 8,640 



Unwrapped 6, 660 5, 580 , 12, 240 



100—11 



Total 

 trees. 



