58 SEEDLING PKOPAGATION OF VARIETIES. 



The disease is not necessarily fatal, but when plants 

 in the seed-bed are attacked by it, the cultivator will 

 almost desire that they had perished outright ; as great 

 numbers of them will be checked so prematurely in 

 their growth, as to be unable to endure the rigor of 

 the next winter. 



On the iirst appearance of the disease, small brown 

 spots are seen upon the under side of the leaves of the 

 weaker plants in the seed-bed or nursery rows, which 

 spread quickly over the whole leaf, and in a few days, 

 over the entire collection of plants. Growth stops at 

 once, the leaves fall, and budding for that season is 

 of course prevented. At this period all nostrums and 

 chemicals are useless. Tlie fact that this disease pre- 

 vails most in old nursery grounds, and indeed is 

 almost confined to soils long cultivated, points to the 

 necessity of restoring to the soil its original qualities, 

 or of planting only in new soils. The disease is doubt- 

 less of fungous character, and as its appearance on 

 the leaf would indicate, is highly contagious. As 

 remarked twenty years since, it is much more pre- 

 valent upon the leaves of seedling stocks than ujjon 

 those of budded and fine varieties. Buds set in stocks 

 attacked with this pestilence, and which have suffi- 

 cient vitality for growth, produce healthy trees, whose 

 leaves remain unspotted. This has afforded a curious 

 subject for speculation among pomologists. 



Mr. Downing supposed this disease to be identical 

 with the cracking and cankering of the fruit of some 

 varieties. 



Some kinds of pear trees in bearing in my grounds 

 are slightly attacked every year, but the disease makes 



