i92o] BROWN— ROT Of DATE FRUIT 529 



agar cultures numerous perithecium-like, carbonaceous structures 

 have appeared, which are now under histological and physiological 

 investigation. In no instance, thus far, have they produced spores 

 on artificial media, nor do they appear on infected material that 

 has been examined. 



* 



An important phase of the date rot problem is the difficulty 

 with which stored fruits are kept. Since another investigator is 

 working on methods of preserving date fruit, it will suffice to 

 state that the same saprophytic molds that occur in infected 

 petioles, rhachi, and fruits on the tree are likely later to ruin the 

 packed crop. 



Conclusions. — From the writer's preliminary observations and 

 experiments, it appears probable that the primary cause of rot 

 and mummification of the date fruit is the attack of Alternaria. 

 This attack paves the way for the entrance of saprophytic Asper- 

 gillus and Penicillium species which bring on the disintegration of 

 the pulp. Commonly all three fungi appear in cultures from the 

 same infected spot. Attack of the spot fungus, unaccompanied by 

 the saprophytic Aspergillus and Penicillium, results in mummi- 

 fication without the appearance of rot. 



Literature. — There appears to be no literature available on 

 diseases of the date in this country, a statement borne out by 

 communications from the Bureau of Plant Industry. Some 

 European investigators have mentioned a species of Sterigmato- 

 cystis as the cause of the rot of date fruit in Africa, but this fungus 

 has not yet appeared on any of the Arizona material examined. 

 Meliola has also been mentioned in connection with the spot of 

 the leaf of date palms, but it also is absent from cultures made in 

 this laboratory. Further study is needed to determine the species 

 of Alternaria , Aspergillus, and Penicillium isolated in cultures. 

 This work, together with histological investigation and inoculation 

 experiments, is already under way, and it is hoped that a further 

 report may be ready soon. 



Agricultural Experiment Station 



University of Arizona 

 Tucson, Ariz. 



