VIII 

 INSECT CONTROL 



THE study of parasitic and predaceous insects is not by 

 any means new. Aldrovandi, an Italian naturalist, appears 

 to have been the first in the field when, in 1602, he observed 

 the exit of the larvae of Apanteles glomeratus from the 

 common cabbage caterpillar. Not, however, till nearly a 

 century later was the true significance of the phenomenon 

 realised by another Italian scientist, Vallisnieri. To enumer- 

 ate but a fraction of the names of the workers in this inter- 

 esting field would occupy too much valuable space ; but it 

 is of interest to note that Ratzeburg, whose work on the 

 subject was for long considered the best contribution in 

 Europe to our knowledge of insect parasitism, "did not 

 believe that insect control could in any way be facilitated 

 by man." 



Probably the earliest workers to suggest the artificial 

 handling of beneficial insects were Kirby and Spence, 

 who, in their work on entomology, published in 1816, 

 referring to the destruction of the hop aphis by the common 

 ladybird, said, " If we could but discover a mode of increas- 

 ing these insects (ladybirds) at will, we might not only 

 clean our hot-houses of aphides by their means, but render 

 our crops of hops much more certain than they are now." 

 Records seem to point to Professor Boisgiraud of Poitiers 

 as being the first man to utilise beneficial against injurious 

 insects. In 1840, or thereabouts, he freed some trees of 

 the harmful gipsy moth by placing upon them the beetle, 

 Calosoma sycophanta ; and also destroyed earwigs by means 



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