198 



AGRICULTURAL REPORT. 



J. M. Aslicr, of the Fruitvale Nursery, Paradise Valley, National City, 

 California, writes to tlic Departineut imder elate October 28, 1872, as 

 follov.s : " One of your writers suggests lye as a remedy for yellovrs of 

 the peach trees. Our soil in California is more or less impregnated 

 wifh allcali, and I ugvqt have seen a case of yellows in the State." 



POTATO ELIGHT AND EOT. 



The potato-disease was first observed in Germany, ilear Li^ge, in 

 1842; in Canada in 1844, and in England in 1845. In the following 

 year it prevailed very extensively over almost all parts of Europe. The 

 summer was unusually cloudy and moist, a circumstance which doubt- 

 less had great effect in fostering tha diseas^. It has been estimated 

 that the damage sustained by Great Britain and Ireland in the year 

 1845 was not less than £21,000,000, and in 1846 probably twice that 

 amount. The London Times estimates that the loss sustained by Gieat 

 Britain during the present year, in consequence of this disease, will be 

 from twenty to thirty millions sterling. * 



For thirty years past the potato-rot has been attributed to a parasitic 

 fungus, known as Botrytis infesfans, but the recent microscopic re- 

 searches of Dr. Payeu have resulted in the discovery of a form of fun- 

 gus in the diseased potatoes not heretofore observed. It is thought, 

 however, by Berkeley and others, that the new form detected by Dr. 

 Payen is probably a secondary fruit (oospore) of the Botrytis itself, 

 the habits of which are not yet fully understood, although many of the 

 ablest investigators of Europe liave for years past been devoting more 

 or less attention to the subject. It has been observed that the fungus 

 attacks the stalks, first causing brown blotches. The disease is next 

 transmitted to the tubers. If we take a withered stalk, which has de- 

 cayed in consequence of the fungus, it will be found that the brown 

 markings have ripened into forms similar to those discovered by Dr. 

 Payen ; and if a longitudinal section of the stalk is made, it will be seen 

 that the interior is also covered with these spores highly matured and 

 generally connected with a very slender jointed light-brown mycelium. 

 The dark rounded forms are visible to the naked eye, but when viewed 

 under a power of fifty diame- 

 ters they appear to vary in 

 size, although with this power 

 they generally appear to be 

 about the size of a large pea. 

 Some are elongated, and all 

 are of a very dark-brown 

 color. 



Fig. 33 represents various 

 fungoid conccptacles which 

 I have found on the interior 

 of the stalk. When highly 

 matured they are covered 

 with dark-brown, rigid, thorn- 

 like appendages, having a^ 

 slightly wavy appearance. 



Fig.3>4. B represents a Ion g- 

 itudinal section of the stalks ; 

 1, 2, 3, 4, dotted ducts ; 5 and 

 0, spiral ducts; 4 and C are 

 represented as being choked 

 up \)y means of budding spores. 



Fiff. 33. 



which were probably absorbed as 



