I3th February, A. D. 1896. 



ESSAY 



BY 



E. H. FORBUSH, Director of Gypsy Moth Work, Massachusetts 

 Board of Agriculture. 



Theme: — Injurious Insects. 



When man first began to till the soil with a view to cultivating such 

 plants as would be useful in furnishing food he instituted many 

 changes in his relations with the material world. By removing or 

 destroying certain plants which cumbered the ground, and planting 

 and cultivating others, he began to disturb the balance of nature. 

 Many animals which had before been considered beneficial or neutral 

 to his interests became his enemies. Especially was this true of those 

 animals which fed upon his crops, and of these the vegetable-feeding 

 insects soon became the most important because the most difficult to 

 deal with. To learn how to destroy or hold in check insects which are 

 injurious to crops has always been one of the aims of the agricul- 

 turist, and this is especially true in a country like our own, which is 

 of comparatively recent settlement. 



A considerable proportion of the land in America is still unculti- 

 vated, and there are vast tracts in which insects can breed unmolested 

 until they exhaust their feeding-grounds and overwhelm the surround- 

 ing country, as in the case of the migratory locusts. In the settle- 

 ment and development of a new country, man at once begins to dis- 

 turb the long-established relations between living organisms. In a 

 wooded country the forests are cut off, the larger birds and mammals 

 are exterminated or driven away, and great disturbances occur in the 

 economy of nature as a consequence of these changes ; new plants are 

 introduced, and with them new insect pests are brought in from other 

 regions or from foreign countries. As civilization advances large 

 areas are devoted to special crops, like the great grain farms of the 



