4 6 



Wart Disease of Potatoes. 



[APRIL, 



It is found on the ground in woods, &c. The flavour is 

 much the same as that of the Parasol Mushroom. 



Chocolate Agaric (Lepiota emplastra) (Fig. io). 



The cap is globose when young, and covered with a 

 parchment-like chocolate-coloured skin, which soon becomes 

 rigid, hence, as the cap expands, the coloured skin is broken 

 up into irregular patches, showing the white flesh under- 

 neath ; 3 to 4 inches across ; gills persistently white, stem 

 stout, white, with a ring or frill near the top. The white flesh 

 of the cap and stem becomes stained dull reddish-brown at 

 once when cut. 



This fungus always grows under cedars and other conifers, 

 and may be found in late summer and autumn. 



The flavour is excellent, but the fungus is not common. 



In a previous number of this Journal * some account was 

 given of the advantages derived from the " greening" of 



potatoes intended for " seed." Further 

 Wart Disease of experiments prove that Wart Disease 

 Potatoes checked by can be checked to some extent by 

 " Greening." planting "greened " potatoes. "Up-to- 



Date," a variety very susceptible to the 

 disease, was used for the experiment. Six potatoes that had 

 been "greened" for a period of six weeks, counted from the 

 time they were lifted, and six that had been kept in darkness 

 for an equal period of time, were selected. The "greened" 

 potatoes had very short, dark green sprouts, whereas the 

 sprouts on the potatoes kept in darkness were quite colour- 

 less and also very short. The twelve potatoes were planted 

 in pairs — one greened and one ungreened — in soil that had 

 been thoroughly inoculated with the fungus causing Wart 

 Disease. After an interval of six weeks the potatoes were 

 examined, when five of the ungreened ones were found to be 

 infected with the fungus. Two of the potatoes had all the 

 sprouts infected ; three each had one sprout infected, the 

 remaining example being quite free from disease. The six 

 greened potatoes were perfectly free from infection with the 

 exception of one sprout that had developed since the tuber was 



* Vol. xvi, No. 3, June, 1909. 



