Rural School Leaflet 



1257 



We arc constantly and unwittingly creating troubles of our own of this 

 kind. The Colorado potato beetle is an interesting and illuminating case 

 in point. 



Prior to 1850 the Colorado potato beetle was confined to the eastern 

 slopes of the Rocky Mountains, notably in Colorado, where it fed on its 

 wild food plant, the sand bur, a relative of the Irish potato. When the 

 settlers began to cultivate the Irish potato in the West, the beetle spread 

 from its original food plant, the sand bur, to the potato, on which it throve 

 prodigiously. It had suddenly found a tender, succulent food plant, 

 eminently suited to its taste and conveniently growing in large patches, 

 extending from Colorado to the Atlantic seaboard and south to the Gulf 

 of Mexico. Nothing was more inevitable than that this insect should 

 gradually extend its territory to coincide with its newly found food plant. 

 From 1868 to 1870 it 

 entered New York State 

 and has since remained 

 as a pest wth which 

 we must contend yearly. 

 Thus we find that in- 

 sects once imknown as 

 injurious suddenl}' be- 

 come serious pests 

 through the disturbing 

 influences of man. 



The natural food 



plants of the common p,,^/^- ^j ^ cabbage leaf slwwing stages in the life history of 



white grubs are the the imported cabbage butterfly, with eggs at A , caterpillars 



,,-- , T at B, and chrysalis at C 

 different grasses. in 



the pasttire lands and in many of the older meadow areas of this 



country there will always be found more or less of these larvae of the 



June bugs. When old pasture or meadow is plowed, and when corn is 



planted on the sod, injuries from white grubs are very likely to become 



serious. So long as the food plants of the June bug larvae stand on the 



soil in abundance, the grubs will thrive and multiply, but their injuries 



may remain wholly unnoticed. On the other hand, when the grasses, 



standing thick on the ground, are destroyed by plowing, and com is planted 



here and there instead, the ravages of the grubs often become prominent 



and widespread. The nimiber of grubs remains practically the same, 



but the food plants are tremendously reduced in number; consequently 



the injuries become very much more noticeable and serious. It is simply 



another case in which man has unwittingly destroyed the balance in nature 



and brought troubles on his own shoulders. 





