T62 TEANSACTIONS OF THE ILLINOIS 



Cherries of the Kentish and Morello families have gradually 

 died from the effects of cold and foliage diseases, and all the fruit 

 except the very earliest varieties has been rendered worthless by the 

 young of the plum curculio. 



Our cherry trees could withs1;and the severe cold, but could not 

 withstand both the cold and a peculiar fungus disease of the foliage, 

 which made its advent into my neighborhood about fifteen years ago. 

 This disease spread from the south here, and became in time so viru- 

 lent as to destroy not only aged trees, but also stocks and seedlings, 

 and was so destructive that for eight years I could grow no cherry 

 trees at all in the nursery. Of the sweet cherries, Early Purple, 

 Guigne and Gov. Wood are nearly exempt from this leaf blight. 

 This is the onli/ reason, I think, why these varieties are hardier than 

 other sweet cherries. The sweet cherries seem to be more liable to 

 the attacks of this fungus, but when introduced, soon becomes viru- 

 lent. All, even the Mahaleb, in favorable seasons for its develop- 

 ment, were completely destroyed. 



I conclude, from careful observation, that this fungus often 

 finds its nidus, breeding place or starting point in the wounds made 

 in the leaves by leaf-lice, plant-bugs and other insects that feed on 

 the foliage. It is not the result of weakness of the tree, caused by 

 severe cold, for when it became epidemic it killed seedlings of the 

 first year. 



It is a well known law in vegetable physiology, that any cause 

 that injures the foliage weakens the whole system of the tree. If 

 the functions of the foliage are entirely destroyed for a time in mid- 

 summer every part of the tree loses its vitality. Just so far as the 

 foliage is weakened in midsummer or a little after, just so far are the 

 roots weakened. Weakened roots lead to a weak and delicate growth 

 the following season, with great liability to disease. In such cases, 

 if severe cold intervenes, the tree is dead. 



I wish here to emphasize this point, that to have hardy health- 

 ful trees, they must have healthy foliage throughout the season. I 

 have had good proof in ray personal experience that it is a fact that 

 in many cases one fruit tree is only hardier than another in so far 

 as its foliage remains entirely healthy during the season of growth. 

 As an example that this is partially true, at least, I would refer to 

 a large nursery of three-year-old apple trees, ou my place, that was 

 well-nigh entirely kept defoliated during the summer of 1873, and 

 until late in autumn, by the Lesser Apple-Leaf Folder (Le Barron). 

 The winter following was a severe one, and the spring following 

 they were all found, as we say, winter-killed. The Duchess of 

 Oldenburg, Red Astrachan, Fameuse, etc., as badly as any others. I 

 believe the Duchess was in the worst condition of any. Now it so 

 happened that there was a small portion of this nursery on very 

 deep, rich, moist soil, where the foliage was not acceptable to the 

 taste of this caterpillar, and they escaped defoliation. Some of what 



