176 
Crown-Gall and Hairy-Root.—In connection with the article on 
Crown-Gall recently published in the Bulletin (K.B., 1910, pp. 309- 
312) it is of ene to call attention to the researches of 
Dr. George G. Hedgecock on Crown-Gall and Hairy-Root of the 
apple tree published at the ci of last year by the U.S. 
Department of Agriculture (U.S. Dept. Agric, Bull. No. 186), 
Dr. Hedgecock has conducted a very comprehensive series of 
experiments, extending over several years, bearing on the disease 
cnown as * Crow m-Gall” in the United States, and also on the 
abnormal = aaee called “ Hairy-root,” occurring on the roots 
and above-ground parts of apple trees. He concludes that the two 
ci ty although so very dissimilar in general appearance, are in 
reality due es the same organism, and that the disease _ean 
root or on the stem, "and Ney often pee iy ian the cals 
themselves, This form of the disease appears to be unknown in 
this country, but has been noted on the Continent. 
In nurseries where trees are propagated by budding and root- 
grafting, as compared with seedling nurseries, there is a muce 
greater percentage of disease, ae on trees grown from root-grafts 
there is more disease than on those propagated on seedlings by 
budding. This is due to the infection of the plants through the 
callus formed at the junction of the graft. The relative amount 
of callus formed depends on the accuracy in graftin When 
close-fitting root-grafts are made, avoiding blunt ends of root 
and scion, which should be approximately ‘of the same diameter, 
but little ‘callus is formed. The wrapping used should consist of 
cloth, and should cover the union completely, and should hold the 
parts firmly together ety the graft is planted, then it should rot 
away when growth begi 
Heavy wet soils hace ‘ee found to fayour an increase of the 
disease, 
A more recent and voluminous Bulletin entitled “ Crown-Gall of 
Plants ; a its cause and remedy ” (U.S. Dept. Agr., Bureau of Plant 
Industry, Bull, No. 213, 1911) embodies pe researches of Dr, Erwin 
I. Smith, Nellie A. Brown and C. O. Townsend. 
Overwhelming evidence as to the bacterial nature of the disease 
cised, 
The measures recommeniied for dealing with the dinéaae are 
nursery stock, condemnation of all diseased shrubs and treés and 
sterilisation of infected soils, 
oe M, 
