48 STATE POMOLOGICAL SOCIETY. 



DISEASES ATTACKING OUR FRUITS. 

 By Prof. S. T. Maynard. 



In the study of the plants about us we find two great classes ; 

 those having green leaves — which, taking up the elements, carbon 

 from the air, and potash, lime, phosphoric acid and other mineral 

 elements from the soil, transform them into their own organism — 

 and those having no green parts with which to assimilate or organ- 

 ize the crude materials from the soil and air, but are parasitic, tak- 

 ing their food from the organized material of other plants. 



Parasitic plants are all more or less alike in that they obtain their 

 food from other plants, but differ as much from one another as do 

 the higher plants From their minute structure they are very difficult 

 to detect, except by their eflfect upon the host- plant, without the aid 

 of the microscope, but are found in all d^artments of the farm and 

 garden. 



Perhaps we may say these diseases are the results of our advanced 

 methods of cultivation, for in new countries they are less abundant 

 and less destructive. With our efforts to produce abnormal growths 

 and the removal of the natural protection of forests ; with the 

 unnatural conditions produced by pruning, by manuring and by cul- 

 tivation, have come the conditions under which blights, rusts, mil- 

 dews, etc., can develop rapidly. 



It is claimed by the P^ntomological Department at Washington 

 that the loss to our farmers from insects in a single 3'ear amounts to 

 over $200,000,000, and with our experience from blights, rusts, 

 smuts, rots and mildews, we feel certain that the loss must be far 

 greater from fungus growths. 



Parasitic plants, destructive to our fruits, may be divided into two 

 classes, i. e., those growing within the host-plant wholly, as the 

 blight of the pear, the yellows of the peach, etc. — and those which 

 root in the tissues, but grow upon the outside of the host- plant as 

 well, such as the mildews, rusts, etc. 



BLIGHTS, 



The first class consist of very minute unicellular plants often 

 called bacteria, microbes, germs, etc., which feed and grow very 

 rapidly under conditions of a certain stage of decomposition of the 

 cell contents of the host-plant. 



