INJURIOUS INSECTS AND FUNGI. 285 



There are a great many other less injurious insects that 

 often appear in small numbers on single trees or within 

 limited localities, sometimes increasing rapidly for a time 

 and then disappearing; but the limits of this volume will 

 not allow of further space for their description. We may 

 briefly say that in a general way the remedies already 

 described may be applied to all insect pests, i.e., all chew- 

 ing insects to be destroyed by the use of Paris green and all 

 sucking insects by the kerosene emulsion. 



Whenever a new insect appears, if doing harm to any 

 crops, specimens should be sent to the entomologist of the 

 experiment-station of the State in which it is found, and 

 the instruction given for its destruction be followed. These 

 stations are established for the purpose of aiding the people 

 to overcome all difficulties in the growth of ornamental 

 or useful crops, and every citizen should be free to ask for 

 instruction and aid whenever needed. 



Fungi Injurious to Ornamental Trees, Shrubs, etc. 



The fungous growths that are injurious to growing plants 

 belong to the group of plants known as parasitic fungi and 

 take their food from their host plant, i.e., the plant upon 

 which they grow, but organize no plant-food for them- 

 selves, and often they feed and grow with such rapidity as 

 in a short time to destroy the host plant or seriously 

 weaken it. Most of these parasites propagate from very 

 minute seed-like bodies already described. They grow 

 under favorable conditions with the most incredible 

 rapidity, as may be illustrated by the short time in which 

 the leaves of a pear or poplar tree are destroyed by the 

 pear-blight or the poplar-rust. It often takes but a few 

 days of warm, moist weather to cause the destruction of all 

 of the leaves of many trees, when perhaps the growth of 



