88 STATE HORTICULTURAL SOCIETY. 



to our shores is allowed to continue unchecked, it will be even more dis- 

 astrous to the plum orchards of Oceana county if the various fungous dis- 

 eases which have caused plum culture to be almost abandoned in many of 

 the eastern states shall gain a foothold in their midst. 



" It therefore behooves each and every one to stand up for restricting 

 their immigration, and not only to be able to recognize them on their first 

 appearance, but to acquaint themselves with the best methods of destroy- 

 ing them. It may seem absurd to warn the fruitgrowers of this section of 

 the state, where diseases of the plum are unknown, against harboring them, 

 but other portions of the country have also thought themselves safe, and 

 at last woke up with their fruit rotting and their trees dying around them. 

 Forewarned should be forearmed. Secure as the plum crop may seem in 

 this section, it is by no meaus siire that it will always remain so, as at any 

 time one or more of the diseases that have proved disastrous in other 

 localities may appear here. 



"Although other fruits may have more diseases attacking them, none are 

 subject to as virulent ones. The plum has some half dozen plant para- 

 sites, any one of which, if allowed to become firmly seated, will destroy the 

 crop and perhaps the tree itself. Some of them attack the trunk and 

 branches, others the fruit or the leaves; and in one case the blossoms, 

 leaves and fruit are attacked by the same one. These diseases are caused 

 by the development, within the tissues of the plum, of minute plants that 

 feed on the juices of their host, and by thus depriving it of its nourish- 

 ment, greatly weaken it. 



" These microscopic plants are known as fungi, and from the fact that 

 they live on animals and on other plants, many of them are called para- 

 sitic fungi. AVe generally associate with the idea of a plant, certain 

 organs that make up its structure, as the root, stem, leaves, and fruit, and 

 although they are greatly modified in their forms, the fungi, such as the 

 mildews, rusts and smuts, possess such organs, the only ones that are 

 lacking being the leaves. 



"Our common plants feed on various mineral substances taken up from 

 the air and soil, which must be changed into organic compounds before 

 they can be used for the building up of the plant. To perform this is the 

 principal function of the leaves. The fungi, feeding on the sap of other 

 plants, that has already been prepared by the leaves, have no need for 

 leaves of their own; and Nature, being very economical, has not taken the 

 trouble to supply them, or if they formerly possessed them they have 

 gradually atrophied through disuse. The toad-stools and puff-balls belong- 

 to one class of fungi, but in most cases their structure is very minute, and 

 can only be made out by means of the microscope. 



GERMINATION AND GEOWTH OF THE FUNGI. 



"The roots of the fimgi, or the parts by which they obtain their food 

 from their host, are minute, thread-like organs. In some fungi they enter 

 the tissues and penetrate the cells of which the plants are made up. In 

 others they pass around between the cells, through the so-called inter- 

 cellular spaces, and instead of entering the cells they send out short 

 branches, or suckers, called haustoria, which pass through the cell wall 

 and extract nourishment for the purpose of building up the structure of 

 the fungus. In still a third class, as in some of the mildews, the threads 

 remain on' the outside of their host, but the haustoria penetrate the ejjider- 



