DISEASES AND PESTS 151 



need be feared from it. Reinfection of a palm that 

 has been cleaned up is easily accomplished, however, 

 if there are infected palms in the vicinity, for the 

 scale is readily carried by birds and animals, or even 

 by ants and other insects. 



Eventually a parasite may be found which will 

 keep the Parlatoria scale in check. Several California 

 lady-birds already prey upon it, while in Algeria it is 

 attacked and perforated extensively by a parasite 

 which has not yet been made the subject of study.* 



This scale, therefore, can not now be considered 

 as even a potential menace to the future of the date 

 industry in the United States. 



The Marlatt scale (Phoenicococcus marlatti) 

 was possibly introduced to the United States at the 

 same time, or at any rate on the following importation 

 of offshoots from Africa. The insect is wine-colored, 

 from 1 to 13^ mm. long, and secretes a white, waxy 

 substance, but not a true scale like the Parlatoria. 

 It lives usually at the base of the leaves, inside the 

 palm, where it is almost inaccessible, and is most 

 active during the winter, coming out at intervals to 

 moult. Its life cycle seems to be forty days.t It 

 has not yet received the study it deserves, but it 

 seems probable that when its habits are known it 



*Scale on palms imported from Algeria by the West India 

 Gardens in 1913 was found to be nearly all destroyed. An ant-like 

 insect similar to the parasite of the melon aphis was observed on the 

 palms, and may be the parasite; it could not be captured. 



tFor a more detailed discussion of the technical history of the 

 two scales, see "The Scale Inserts of the Date Palm," by T. D. A. 

 Cockerell and "The Extermination of Date Palm Scales," by R. H. 

 Forbes. Univ. Ariz. Agr. Exp. Sta., Bui. No. 56, Tucson, Sept. 23, 

 1907. Dr. L. Trabut of Algiers describes the Phoenicococcus in 

 Note sur une Maladie du Dattier. Comptes Rendus de TAcademie 

 des Sciences, Paris. T. 154, p. 304. Seance du 29 Janvier, 1912. 



