260 DELIBERATE INTRODUCTION OF NEW ANIMALS 



pests was soon diagnosed, and so long ago as 1860, the use 

 of insect counter-pests had been tried, for the United States 

 Census Report of that year states that the New York 

 Agricultural Society " has introduced into this country from 

 abroad certain parasites which Providence has created to 

 counteract the destructive power of some of these depre- 

 dators." 



In recent years the introduction and use of counter-pests 

 has been carried out with great skill and deliberation. Insects 

 known to attack certain pests have been brought from their 

 native land and reared, particularly in America, in such num- 

 bers that they could be distributed wholesale to the affected 

 areas. One or two examples will be sufficient to make clear 

 the significance of such introductions at the hand of man. 



In 1868, in the early days of the Californian fruit-grow- 

 ing industry, some young orange trees were brought from 

 Australia to the neighbourhood of San Francisco. The trees 

 were infested by an Australian Hemipterous insect the 

 Fluted or Cottony Cushion Scale (Icerya purchasi\ a small 

 inert-looking creature which subsists on the juices of the tree. 

 For many years the pest worked 

 unnoticed, and became so suc- 

 cessfully acclimatized that by 1880 

 it had spread all over the State, 

 causing such terrible devastation in 

 the orange groves of Southern Cali- 

 fornia that in a single year the 

 orange crop was reduced from 8000 

 to 600 waggon loads. Such havoc 

 was caused during the next eight 

 years that Mr A. Koebele, an expert 

 entomologist, was sent by the U nited 

 States Department of Agriculture 

 to Australia to find out by what 

 means Nature there kept the Fluted 

 Scale in check. Koebele found that 

 a brilliant red and black Lady-bird 

 Beetle {Vedalia cardinalis] preyed 

 extensively upon the Scale, and some 500 specimens of the 

 Lady-bird, carefully packed, were sent alive across the seas 

 to California, where they were fed and tended. After a few 



Fig. 49. Cottony or White Scale 

 being attacked by the Cardinal 

 Lady-bird imported to America 

 from Australia to combat it. 

 (Twice natural size.) 



