NURSERY INSPECTION. 
33 
in the Inspection work in the State re'ferred to. In this connection 
it is interesting- to know that, in 1913, officials in 27 states tempo- 
rarily withheld certificates because this scale was present. 
Crown Gall on Raspberries. 
Hardly a nursery in Minnesota is absolutely free from this 
disease. See Figure 3, colored plate, and also PL, facing p. 34. From 
5% to 80% or over of raspberries were found affected in 1914. 
Perhaps Londons are the most susceptible, although no variety 
appears to be absolutely immune. The disease is characterized by 
swellings on the root, as shown (and occasionally on the stem). 
It is also found upon the apple and plum ; it is infectious and can be 
conveyed from cane to apple and vice versa. At one time the 
finding of a large percent of trees infested with crown gall would 
disqualify for certification, but with the lack of any proof of perma- 
nent injury upon the apple in doubt, as it is now, apparently many 
inspectors, Minnesota officials included, take but little note of 
affected apples. They are necessarily strict when the disease is 
found upon canes, for whatever the effect upon fruit trees, we 
know absolutely that it greatly weakens and kills raspberry plants, 
and have found hundreds of these plants in Minnesota dying from 
this disease. We have urged patrons of nurseries to scrutinize 
their raspberries, personally, when purchasing. Any consignment 
which shows even a small percentage of infestation should be 
rejected. Such exhaustive experiments have been made upon this 
organism, and so many instances of its infectious nature have been 
proven, that it seems unnecessary to discuss it. Rotation of crops 
and the prompt destruction of diseased plants is advised. One 
nurseryman claims that in planting cuttings he finds that he can, 
to a large extent, avoid infestation by planting deep at least 5 or 6 
inches. This feature has not been made a matter of Station experi- 
mentation. It may be undertaken later. In the latitude of St. Paul, 
diseased plants of bearing age can easily be detected by their scant 
and drooping, frequently yellowing foliage. Such plants, if pulled, 
almost invariably show crown gall on roots. However, plants 
which look healthy above ground, ma}^ also occasionally bear gall 
below the surface. In 1913 inspection officials in 15 states withheld 
certificates temporarily on account of the presence of this disease 
in nurseries under their jurisdiction. 
