ROT OF DATE FRUIT 1 



J. G. Brown 



(with five figures) 



In the autumn of 1917, Dr. A. E. Vinson of the Ariz 

 ment Station brought to the writer a small box of dat 

 Yuma date orchard with the reauest that the organism 



determined. The fruits were care- 



examined, but it was im 



mation 



and 



was suggested by 



Professor Thornber, Botanist of the Station, that since the 

 problem concerned food conservation it would be especially 

 profitable to attack it at once. The advice was acted upon, and 

 the results are partly set forth in this preliminary paper. 



For the purpose of observing the disease in the field, a trip was 

 made to the orchard in December 191 7, and a careful inspection 

 of trees and fruit was undertaken. A glance at the figures will 

 show that abundant evidence of disease was not difficult to find. 

 The ground under many of the trees was thickly covered with the 

 spoiled fruit (fig. 1), and numerous clusters still hanging to the 

 trees suggested a severe attack of "plum pockets," for a large per- 

 centage of the fruit had become mummified (fig. 2). Some of the 

 fruit on the ground was covered with molds, and similarly infected 

 fruit was found wedged between the leaf bases and tree trunks 



1 



and on the ground half buried in the soil. Of the several varieties 

 of date palms comprising the orchard, the Deglet Noor appeared 

 to be the favorite host. It was stated that the year had been an 

 especially bad one, about 90-95 per cent of the crop being infected. 

 The fruit was selling at the orchard at 35-45 cents per pound. 

 Since many of the trees produce from 200 to 400 pounds of salable 

 fruit under normal conditions, the loss was considerable. 



Both Yuma and Tempe date orchards were affected much less 

 by the rot in 191 8 than in 191 7. Table I gives precipitation and 



1 Preliminary paper. 



[521 



[Botanical Gazette, yol. 69 



