Insects and Fungi Attacking Trees, Etc. 345 



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 feel 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 a tree, when perhaps the growth of but a few spores only 

 began the work of destruction. It is during hot, moist 

 weather that they grow most rapidly, and while we may 

 sometimes escape if we do not use fungicides, the wise 

 gardener will be prepared and make application of the 

 fungicides described on previous pages. 



Among the many fungi injurious to ornamental trees, 

 shrubs, etc., the following are among the most destructive: 



Rusts. This term has been applied in more or less of 

 an arbitrary manner to a large group of fungi that produce 

 masses of spores on the surface of the leaves or stalks, gen- 

 erally yellowish or brownish in color, but when of a white 



