FUNGI AND FUNGICIDL5. 



Growing plants are liable to the attacks not only of insects, 

 but also of parasitic fungi. The peculiar maladies known as 

 fungous diseases are produced by the rapid development of the 

 parasitic fungi. It is estimated that in the United States alone 

 the annual loss from these minute vegetable organisms runs 

 into millions of dollars. 



Fungi belong to the so-called lower plants, among which are 

 the toadstool, mushroom, molds, mildews, rusts, smuts, blights, 

 etc. A fungus may attack only dead tissue or decaying matter, 

 as is the case with mushrooms or toadstools, or it may attack only 

 animal life, as is seen in the fungus which destroys the house 

 fly and the chinch bug. But the most important class of para- 

 sitic fungi with which the fruit-grower has to deal are those 

 which attack the live tissue of plant life those which check 

 the growth of trees, attack and spot fruit, and even cause an 

 early decay or a total loss before the crop is harvested. 



Fungi are plants, much the same as trees, grass, etc., the 

 only difference being that they do not have the green coloring 

 matter, or chlorophyll, of the latter. The seeds, called spores, 

 are more simple and are exceedingly minute (microscopic). 

 They are produced in numbers which appear almost incredible 

 to those not versed on the subject. 



Fungi are divided into two groups: the internal and the 

 external. The internal fungi send their germ tubes into the 

 skin of the leaf, fruit, branch, or root, and the branching 

 threads (mycelium) develop entirely within the tissue of the 

 host plant. This group includes some of our worst species, such 

 as peach-leaf curl, anthracnose, brown rot, shothole fungus, 

 and all the grain smuts. 



The external fungi are surf ace' feeders, their mycelium spread- 

 ing over the surface of the fruit, leaf, or branch, as the case 

 may be, and are easily controlled by the use of sprays. To this 

 group belong the powdery mildews of the apple, grape, rose, 

 gooseberry, etc. 



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