14 CAUSE AND NATURE OF CROWN-GALL 



gall being upon young trees which they received from as far 

 south as Georgia. These galls grow upon the apple and peach 

 in particular, and it is not unlikely that if large numbers of 

 trees were examined that the whole group to which the peach 

 belongs would prove to be host plants for the disease." — 

 B. D. Halsted. 



" Crown-gall is very abundant in Alabama on the peach, and 

 is sometimes found on the plum. I consider it a very serious 

 peach disease in Mississippi and Georgia, as well as in this 

 State." — F. S. Earle. 



" The crown-gall is present in Ohio. It affects apple, pear, 

 peach, poplar, and raspberry. It is reported to me upon plums 

 and cherries, but I have seen no examples. One peach orchard 

 in Ottawa county, two years planted, is now about 50 per cent, 

 dead or affected with crown-gall. This is the worst case known 

 to me at present. In most cases the disease has apparently 

 come upon stock from the South and East." — A. D. Selby. 



" The crown-gall occurs in California on all our deciduous 

 fruit trees and on grapes. It has been very abundant and se- 

 rious, but I have not heard as much complaint regarding it 

 during the past two years as usual." — C. W. Woodwokth. 



' ' The crown-gall occurs commonly on peaches in Connecticut. 

 My predecessor, Dr. Thaxter, believed that he had established 

 the contagious character of the trouble by means of green-house 

 culture of sound plants in proximity to others infested with 

 crown-gall." — W. C. Sturgis. 



" The crown-gall is just now turning up in several places in 

 Michigan. Our attention has recently been directed to extern 

 sive destruction of nursery stock in certain localities, due to 

 this cause. Last week a nursery at Bangor, Van Buren county, 

 was inspected and fully 25 per cent, of the trees were found 

 infested." — C. F. Wheeler. 



FIELD EXPERIMENTS IN THK SALT RIVER VALLEY. 



My own investigations, aside from field observations, date 

 from the spring of 1896. At this time a series of experiments 

 was begun in a badly infested almond orchard at Glendale. 

 This orchard comprised forty acres, the trees all being of the 

 same age and practically uniform in size and general appear- 

 ance. The field experiments in this orchard extended over a 

 period of three years and were directed toward an effort to as- 



