50 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 



The following specific treatment will be largely confined to pests 

 obseiTed during the writer's travels abroad, which are of economic 

 importance in the United States. 



Spain, Italy, and Sicily. 



ChrysompJialus dictiospermi is the most destructive pest of citrus 

 trees in these three countries. According to Prof. Silvestri, the emi- 

 nent Italian entomologist, this species was first noticed in Italy and 

 Sicily in 1909. Fortunately the infestations of this insect are of a 

 localized nature in these countries. In Spain it is widely distributed 

 and undoubtedly was present here many years before its appearance 

 in Italy. The species is attacked by numerous natural enemies, both 

 parasites and predators, in all three European countries. 



Parlatoria zizyphus, the pest which ranks in point of injuriousness 

 next to Ch. dictiospermi in these three Mediterranean countries, does 

 not occur in citrus groves in the United States. It can thus be seen 

 that the citrus groves of this country are free of the two pests most 

 injurious to the same plants in southern Europe. ChrysompJialus 

 dictiospermi has been reported in greenliouses from most parts of the 

 United States, but no record of the definite establishment of Parla- 

 toria zizypjhus is at present known. 



Lepidosaphes lecHi, Saissetia olese, and Pseudococcus citri, namely, 

 the purple and black scales of California and the citrus mealy bug, 

 wliich are very serious pests in our own country, produce very little 

 serious injury in the Mediterranean region. It should be of the 

 greatest interest to the citrus fruit growers of California, who spend 

 so many hundreds of thousands of dollars annually in combating these 

 pests, to know that in the chief citrus-fruit producing countries of 

 southern Europe these same pests, though present, are for the most 

 part under natural control so that artificial effort is seldom necessary 

 for their subjugation. To quote from a communication respecting 

 this subject received from Prof. Silvestri: 



The other species of citrus pests (which include the purple and black scales and the 

 mealy bug) produce here and there some injury, but not continually nor so great that 

 the cultivator has any interest in attempting to control them with insecticides. Only 

 occasionally does an outbreak occur of such serious nature as to require artificial means 

 of control. 



Lepidosaphes heclcii, the purple scale, was observed in Spain but 

 only in such slight infestations, so far as the writer's observations 

 extended, that it may be said to be under commercial control. Mr. 

 L. Salas, the agricultural engineer of the Province of Malaga, in- 

 formed the writer that the purple scale was once very severe in parts 

 of that Province, but for some unknown reason had suddenly disap- 

 peared in recent years. A similar report was heard from another 

 authority in that Province. In Italy and Sicily the purple scale is 



