INSECT ENEMIES AND REMEDIES. 



BY PROFESSOR JAMES CASSIDAY. 



4 



Insects are among the most formidable enemies to the successful culture 

 of orchard and small fruits in Colorado, as elsewhere, and to combat them 

 successfully requires an exact knowledge of their life, history and habits. 

 Irrigating as we do, however, to promote the growth of crops enables us 

 to hold in check some of these pests which in adjoining States prove so 

 injurious to the labors of both farmer and gardener. 



Our injurious insects may be divided into two classes, according to the 

 construction of their mouth parts. First, those that eat the structure of 

 plants, and having jaws adapted to this end can only be destroyed through 

 the stomach, by poisoning their favorite food plants. The second class 

 have their mouth parts in the form of a beak by means of which they 

 extract the juices of plants, and hence enfeeble if not destroy them. 

 This class of insects, not eating the structure of plants, can be destroyed 

 only by the direct contact of the remedies applied. Hence the remedies 

 employed are grouped into two classes. First, arsenical poisons, killing 

 insect life through the stomach ; the second, represented by alkalies, acids 

 and oil mixtures, are designed to be effective only by direct contact. 

 White hellebore is a vegetable poison and is effective in destroying insect 

 life in both ways. Some insects cannot be combatted successfully by the 

 application of remedies ; they must be met by preventive measures, by 

 which the plant is protected from injury, or the known habits of the 

 insects are so circumvented as to rentier them powerless to do much injury. 



Preventive measures are, first, keeping the plants in a thrifty condi- 

 tion. Every observant plant grower will endorse this. Second, a 

 judicious rotation of crops, and fall plowing. 



ARSENICAL POISONS. 



Paris green is, without doubt, chief among the arsenical compounds, 

 and the most practical for the destruction of insects that eat the structure 

 of plants. If pure it is effective in proportion of one pound to one hun- 

 dred gallons of water. Where any large number of trees or plants are to 



