INSECT PESTS OF DATES IN MESOPOTAMIA. 297 



Other Hosts. — Fide Cockerell (1907), Parlatoria blanchardi has been recorded 

 by Newstead (1906) from jasmine foliage. King (1908) says Draper (1907) has 

 recorded it from yellow jasmine and periwinkle. It does not appear to have been 

 recorded from any other plant. 



Parasites and other Enemies. — Cockerell (1907) records Coccinella ahdominalis 

 and Chilocorus cacti (Coccinellidae) as feeding on this scale in America ; to this 

 (Mthly. BuU. Sacramento, 1913, p. 139) we can add Scymnus sp. Popenoe states 

 that there is a parasite which perforates this scale in Algeria, but it has not yet 

 been investigated. No doubt this is some small Hymenopteron. Cockerell (1907) 

 has once seen the emergence-hole of a Hymenopteron in a scale of P. blanchardi 

 in America. 



In October 1918, at Amara, R. Tigris, in Mesopotamia, I bred a small Eulophid 

 wasp from P. blanchardi. This parasite has been determined by Mr. J. Waterston 

 as Ajphelinus mytilaspidis, Baron. It was extremely common, and it appeared 

 probable that it was an important agent in controlling the scale, which so far as 

 I know is never a serious pest in Mesopotamia. It would probably not prove worth 

 while to import this Eulophid into other countries in which the date is a main crop, 

 because we know that the parasite is already widely distributed. According to 

 Mercet, A'phelinus mytilaspidis has been found in U.S.A., Ceylon, Italy, France, 

 and Spain, and is known to parasitize the following scales : — in America, Lepido- 

 saphes ulmi (Mytilaspis pomorum), Chionaspis pinifolii, and Diaspis carueli ; in 

 Ceylon, Chionaspis permutans and C. graminis ; in Italy, Aspidiotus hederae and 

 A. betulae ; in Spain, A. hederae and Diaspis rosae. It has not apparently been 

 previously recorded from Parlatoria blanchardi. 



Treatment. — Forbes (1907) states that treatment designed to exterminate Parla- 

 toria blanchardi and Phoenicococcus marlatti has to be extremely thorough, because 

 the scale-insects persist, even in small numbers, among the closely crowded bases 

 of the great leaves. The reader must realize that the whole crown of the tree is 

 enveloped in sheets of fibrous matting which arise between the petioles of the leaves 

 where they are inserted on the trunk. Any scale-insects which happen to be in this 

 tightly-bound tangle escape soap and kerosene emulsion, whale-oil soap, distillate 

 spray, resin wash and even fumigation with hydrocyanic acid vapour. There re- 

 main two treatments which are said to be efiicacious. Wilsie (1913) tells us that 

 after the great fire in San Francisco " the ornamental palms withstood the great 

 heat, and put out new leaves at once after the fire." This observation suggested 

 the treatment described by Forbes (1913) ; the trees are pruned down to the crown 

 and all the great leaf bases, and the fibre in which they are set, are removed as much 

 as possible. When the tree has been reduced to a bare pole it is drenched with 

 paraffin and fired, after which the surface is fiamed with a gasolene blast, several 

 times in the first few months, in order to destroy such few pests as may be finding 

 refuge in cracks and similar places. This treatment does not kill the tree but des- 

 troys the Parlatoria and Phoenicococcus. Popenoe (1913) says that the gasolene torch 

 treatment puts the young palm back two years and is unpopular with the growers 

 for that reason. He states that all offsets are now dipped bodily in a tank of cresol 

 dip, and adds that " this destroys the scale so that no danger need be feared from 



