98 MASS. EXPERIMENT STATION BULLETIN 160. 



solution of the problem. The roots were first examined late in May. It 

 was soon found that new rootlets were developing in connection with the 

 unsprayed vines all over the bog. On the sprayed plots, however, there 

 was almost no new root development. It was also noticed early in the 

 season that there was a rather scanty growth of old rootlets near the 

 surface of the sand on the sprayed areas, while on untreated parts of 

 the bog this growth was evidently much more abundant. Moreover, the 

 rootlets near the surface on the plots appeared to be blackened and rather 

 lifeless, as though injured by burning. In June and July the difference 

 in the condition of the roots of the sprayed and unsprayed vines was 

 rather striking. It could be most easily observed by grasping single 

 vines between the thumb and forefinger, close to the surface of the sand, 

 and pulling them up by the roots. When this was done, it was apparent 

 at once that there was no considerable mass of rootlets on the sprayed 

 vines for about an inch below the surface of the sand, while on those that 

 had not been sprayed the rootlets were usually massed close up to the 

 very surface. This condition of the roots seemed to suggest that they 

 had been injured by the spraying in some way. 



Attention is called, in this connection, to the fact that a New Jersey 

 grower of large experience has infonned the writer that he found his vines 

 taking on a similar sickly, reddish appearance after he had been spraying 

 his bog a few years. His vines apparently got into a worse condition than 

 have those on the sprayed plots of the station bog, a considerable dying 

 out taking place among them. The grower, however, laid the trouble to 

 lack of proper plant nutrition, and apphed fertihzers containing nitrates. 

 His vines recovered, taking on a normal green appearance, and are now 

 producing satisfactory crops again. His results in this regard seem to 

 be paralleled — to a considerable extent — by those obtained on the 

 station bog with plot A, the middle half of which was fertihzed in both 

 1913 and 1914, as stated in another place. The \dnes remained green 

 and thrifty on the fertilized part of this plot, while the unfertiUzed parts 

 took on the reddened appearance that has been described. In both 1913 

 and 1914, however, the fertilized part of this plot failed to produce any- 

 where near as much fruit as did the surrounding unsprayed portions of 

 the bog. Wliile it is by no means certain that the New Jersey grower's 

 difficulty was caused in the same way as that on the station bog, the 

 comparison is certainly suggestive. 



To get further light on this whole problem, and to determine definitely 

 in what ways spraying with Bordeaux mixture does injury, special spray- 

 ing experiments were started on small plots, the sprays appHed being made 

 up with varying proportions of hme and copper-sulfate, resin fish-oil 

 soap being used with some and being left out with others. These sprays 

 were apphed in excessive quantities (25 gallons to the square rod) so 

 that they would soak into the ground and come in contact with the 

 roots thoroughly. If these experiments show that Bordeaux mixture 

 necessarily causes considerable injury to cranberry bogs, general spray- 



