February, T8] FRACKER: CROWN GALL AND APPLE NURSERY STOCK 133 
base up, while heretofore the basal branches have been cut off close 
to the trunk. This will doubtless have the effect of decreasing the 
disease. It seems wise to recommend that poplar trees should not be 
pruned to any great extent in any part. Poplar trees should have good 
drainage and proper precautions should be exercised against the use of 
cuttings from diseased trees. In blocks of poplars growing on low¬ 
lands the virulency of the disease was greater. 
The utility of the Lombardy poplar for screening unsightly objects 
or for giving accent to an otherwise monotonous group of trees or 
shrubs is recognized by nurserymen and landscape architects. Its 
popularity as a tree for framing in a view is not questioned and they 
are often very effective for planting close against houses, particularly 
of the English style. While no other substitutes could fill all the 
conditions desirable in trees of this type, there are several trees of 
similar habit and more permanent beauty. The maiden-hair tree 
('Gingko biloba), the Katsura tree (Cercidiphyllum japonicum ) and 
the pyramidal varieties of sugar maple, English oak and the tulip tree 
comprise a list which should suggest a worthy substitute in case the 
poplar canker does not prove amenable to treatment. 
IS CROWN GALL INJURIOUS TO APPLE NURSERY STOCK? 
By S. B. Fracker, Assistant Entomologist , Madison, Wis. 
Under Wisconsin conditions the presence of crown gall and hairy 
root on apple trees is the cause of a greater commercial loss to the 
nurseryman than any other disease. The toll taken by the required 
destruction of all trees infected with it is very heavy. At the same time 
there is a real doubt in the minds of the nursery proprietors as to the 
serious or injurious nature of the trouble. 
This doubt is increased by the published results of experimental 
plantings in New York, 1 by the opinion expressed in a U. S. Depart¬ 
ment of Agriculture bulletin 2 that the effects of crown gall have been 
greatly exaggerated, and by the fairly well advertised presence in a 
neighboring state of a flourishing orchard planted entirely with trees 
bearing large galls. 
The writer, therefore, during the last autumn packing house inspec¬ 
tion seized the opportunity of making some observations in regard to 
the relative size of infected and non-infected nursery trees. In all 
cases the grading into sizes was done by the nurseryman himself and 
X F. C. Stewart, N. Y. Ag. Exp. Sta. Bui. 328 (1910), pp. 311, 312. 
2 Hedgcock, U. S. Bur. Plant Incl. Bui. 186 (1910), p. 72. 
