226 PLANT PROPAGATION 



growth will have started. The plants may then be hardened oft 

 and transplanted in the field. 



Advantages of this method are that grafting is simplified, since 

 no tying is needed, the grafts are placed in the box as made without 

 unnecessary handling, a development of vegetation is secured in 

 three weeks equal to that of two months by ordinary outdoor prac- 

 tice, a more perfect union and callus are secured and disbudding of 

 the stock is unnecessary. 



294. Dressings for tree wounds. Fruit growers have long used 

 paints, tars, waxes and other substances as coverings for wounds 

 on trees. The New York state station reports results of experi- 

 ments with white lead, white zinc, yellow ocher, coal tar, shellac 

 and avenarius carbolineum. The summary of Bulletin 396 by Howe 

 is slightly condensed in this and the next paragraph. In all cases 

 undressed pruning wounds have healed more rapidly than those 

 whose surfaces have been protected. The first season shellac 

 seemed to exert a stimulating influence on wounds, but the second 

 season this disappeared. Of all materials used shellac was least 

 injurious, but it adheres to wounded surfaces poorest of all. Car- 

 bolineum and ocher caused so much injury that neither should be 

 used. Coal tar not only caused injury, but quickly disappeared, 

 either .through evaporation or absorption. White lead and zinc 

 caused some injury when applied, but the wounded tissues recovered 

 rather quickly, and at the end of the first year the injury was not 

 very marked; at the close of the second season it had nearly dis- 

 appeared. These two are the best protective substances used, and 

 of the two white lead is the better. Nothing is to be gained in 

 treating wounds by waiting before applying the dressings. 



The treatment of peach tree wounds with any of the substances 

 caused so much injury that it may be said peach wounds should 

 never be treated with any of them. This may be inferred for 

 other stone fruit trees. There is nothing lo show in the experiment 

 that it is worth while to treat wounds large or small with any of 

 the substances in common use. Had there been a longer period of 

 observation, it might have been found that wood exposed in the 

 larger wounds would have been somewhat saved from decay which 

 often sets in on exposed wood of fruit trees. It may prove to be 

 worth while, therefore, to cover large wounds, in which case white 

 lead is undoubtedly the best dressing to use. 



