Spray Calendar. 65 



WHAT IS THE HOST-PLANT ? 



The host-plant is the plant upon which, or in which, the fungus 

 lives and from which it draws its food supplies. 



WHAT IS A FUNGICIDE? 



A fungicide is ajiy substance which may be used to destroy fungi 

 or their spores, or which will prevent fungi from establishing them- 

 selves upon the host-plants. Fungicides may be either solids, 

 liquids, or gases. The most common forms of fungicide is liquid; 

 the kind of fungicide used, however, must depend upon the nature 

 of the fungus, the nature of the host-plant, and the part of the host- 

 plant attacked by the fungus. 



WHY SHOULD WE SPRAY ? 



Liquid fungicides are best applied in the form of a fine mist or 

 spray. This is economy, both in the quantity of material used, and 

 in the time required to apply it. The real object in spraying is to 

 prevent the fungous spores that have lodged upon the foliage, 

 branches or fruit, from germinating and producing fungous 

 growths. Every fungus that grows into a leaf or into a fruit, and 

 thus produces the destruction of the former or the decay of the 

 latter, first lodges on the leaf or on the fruit as a tiny spore. If 

 that spore can be destroyed without injury to the leaf or the fruit, 

 disease may be prevented, and therefore the necessity of spraying. 



WHY SHOULD W^ SPRAY EARLY? 



As already stated, fungus spores are sometimes formed in the 

 fall and remain in open fields all winter uninjured. These spores 

 often lodge in the crevices of the bark of trees, or in other conven- 

 ient places on the trunk and branches of trees. When the leaves and 

 fruits appear the spores are blown onto these newly-formed parts and 

 cause them to be diseased. The object in early spraying, even while 

 the trees are still dormant, is to kill the spores that are lodged on 

 the tree and waiting for favorable conditions for development. 

 Again, every spore must remain for a longer or shorter time in a 

 dormant state, even after it reaches the proper place for its devel- 

 opment, just as seeds' remain for a little time under proper condi- 

 tions for germination before they begin their growth. If the leaves 

 HoR. 5 



