No. 7. 



DEPARTMENT OP AGRICULTUPwE. 



213 



selves to explain in simple language the nature of a fungous dis- 

 ease, I take my students into the orchard and have them point out 

 every imperfection in the tree and the blemishes upon the fruit and 

 endeavor to train their eyes in discerning the symptoms peculiar to 

 each disease. I hold in my hand an apple taken from a student's 

 laboratory desk. One side of this apple was punctured several times 

 with a needle; the holes dried up so that it is difficult to see where 

 they are. On the other side of the apple a similar number of punc- 

 tures was made after the needle touched the spores of the fungus 

 which caused the total decay of a plum. In two days the decay of 

 the apple was showing about these punctures and now after six 

 days you can see that more than half of the apple is brown with 

 decay. Is it not clear then that this side has been inoculated? The 

 invisible spores were carried to the apple and in 24 hours these spores 

 germinated and began to cause the decay of the apple and after six 

 days we find on this apple a new crop of spores. Now the student 

 observes that this rot has particular symptoms which can be dis- 

 tinguished with the naked eye and further corroborated with the 

 microscope. Two rots are shown on this specimen and if you 

 could examine it closely you would recognize differences. There are 

 also unsightly spots of apple scab, and insect injuries. All these 

 things have been made matters of careful investigation by officers 

 of our Experiment Stations and reports are available to every per- 

 son interested in the subject. 



On the matter of feeding orchards, too little is said by the institute 

 lecturers and much less is done by the average fruit grower or farmer. 

 The latter is convinced that to get a good crop of wheat on his farm 

 he must first fertilize his land, but he does not realize that an or- 

 chard in bearing removes annually from the soil several times more 

 nitrogen, phosphoric acid and potash than does a crop of wheat. Or- 

 chards seldom receive fertilizers except incidentally. 



The following figures show the per cent, of several mineral ingre- 

 dients to be found in the ash of the fruit and wood of the apple and 

 serve as an index of the dependence of the apple upon such plant 

 foods : 



Fruit, 

 Tree, 



35.68 

 19.24 



33.59 

 4.90 



l;6.09 

 .45 



8.75 

 7.46 



4.08 

 63.60 



1.40 

 .07 



16 



