EFFECT OF THE DISEASE ON APPLE TREES, Syl 
A fifth orchard, belonging to the Arkansas Agricultural Experiment 
Station, located at Fayetteville, Ark., has been under the observation 
of the writer for five years. This orchard is 15- years old and was 
planted as an experiment to test varieties of apples from a horticul- 
tural standpoint. Twelve out of a hundred trees in this orchard, 
mostly Russian varieties, have developed the aerial form of hairy- 
root, with no apparent effect as yet upon the growth or the fruiting 
of the trees. 
A sixth diseased orchard is situated near Mitchell, Ind., on the farm 
of the Burton Fruit Company. Among other older trees there are 
planted over two hundred Benoni apple trees now 8 years old. This 
orchard was visited by the writer in the autumn of 1908. More than 
half of the Benoni trees are diseased with the aerial form of hairy-root, 
with little or no apparent effect, as yet, on their growth. Mr. Joseph 
A. Burton, superintendent of the orchard, asserts that many of the 
knots disappear as the trees grow older, but that their immediate 
effect is to make the trees bear younger. In an older orchard belong- 
ing to Mr. Burton there is a thrifty 25-year-old Chenango apple tree 
that has been diseased with the aerial form of hairy-root for years, 
with no effect upon its fruitfulness. 
In summing up the data from these orchards, the results show 
that crown-gall and hairy-root have but little immediate effect on 
the growth of trees in the orchard. Orchards that were reported 
dying from disease have been examined by the writer, but the immedi- 
ate causes on examination have proved to be heart-rot and root-rot, 
usually accompanied in unfavorable soil conditions by poor drainage, 
neglect of cultivation, etc. These diseases apparently attack and 
kill the trees originally healthy, without regard to the presence of 
crown-gall or hairy-root. 
Experimental orchards—The orchard experiments conducted for 
the study of the disease were four in number. ‘The location of these 
orchards, designated as orchards 1, 2, 3, and 4, and a description of 
the soil in each, with the methods of experimentation, are given on 
page 79. 
Orchard 1 was planted with trees of the following varieties: In- 
gram, Gano, Collins, and York Imperial, grown in a nursery in 
eastern Missouri. It was planted with 112 healthy apple trees 
(Pl. III, fig. 3) and 96 diseased with the hard form of crown-gall, the 
galls being near the crowns of the trees, just below the surface of the 
soil as they grew in the nursery (PI. I, fig. 1). This orchard was on 
well-drained soil, and the healthy and diseased trees were planted 
in alternate rows. 
Orchard 2 was planted in a soil similar to that of orchard 1, except 
that it was situated at a lower elevation and was subject to seepage. 
186 
