62 



Annals of Horticulture. 



tionize our dealings with many or most injurious insects. 

 Their use, both in extent of territory covered and in the kinds 

 of insects attacked, is increasing with great rapidity. 



But the boldest stroke in checking insect ravages is the 

 wholesale introduction from a foreign country of parasitic in- 

 sects to prey upon the injurious ones. Perhaps the most 

 destructive insects to fruit trees in this country are the 

 white and red orange scales. These insects have ruined 

 many: orange groves in California, and have caused wide- 

 spread alarm on the Pacific coast. The white scale, Icerya 

 Purchasi, is particularly destructive, and is exceedingly diffi- 

 cult to combat. Professor Riley, of the National Depart- 

 ment of Agriculture, determined that the insect is a native 

 of Australia, where it is kept in check by certain para- 

 sites. A movement was at once set on foot to import 

 these parasites, and two of the agents of the department 

 were dispatched to Australia for this purpose. A lady-bird 

 beetle, known as Vedolia cardinalis, has so far given best re- 

 sults in destroying the scale. Mr. Coquillet, of Los Angeles, 

 who has had charge of the breeding of these insects, describes 

 the progress of the work as follows:* "The first consign- 

 ment of these lady-birds reached me on the 30th of Novem- 

 ber [1888], and numbered twenty-eight specimens; the sec- 

 ond consignment of forty-four specimens arrived December 

 29th, and the third consignment of fifty-seven specimens 

 reached me January 24th, making one hundred and twenty- 

 nine specimens in all. These, as received, were placed under 

 a tent on an icerya-infested orange tree, kindly placed at my 

 disposal by Mr. J. W. Wolfskill, of this city. Here they 

 were allowed to breed unmolested, and early in April it was 

 found that nearly all the iceryas on the inclosed tree had been 

 destroyed by these voracious lady-birds. Accordingly, on the 

 1 2th of April, one side of the tent was removed, and the 

 lady-birds were permitted to spread to the adjoining trees. 

 At this date I began sending out colonies to various parts of 

 the state. ***** gy I2 th of June we had thus 

 sent out 10,555 of these lady-birds, distributing them to two 

 hundred and eight different orchardists, and in nearly every 

 instance the colonizing of these lady-birds on icerya-infested 

 trees in the open air proved successful. The orange and 



*Insect Life, ii. 73. 



