FUNGOID PESTS OF CULTIVATED PLANTS. 103 



mately black. In all other particulars it closely resembles the Potato 

 Sclerotium, except perhaps as to the consequences of a period of rest. 

 We did not attempt to cultivate the sclerotia, but probably there also the 

 results would have been the same. 



This was the first time we were made acquainted with this disease on 

 Cucumbers, but our correspondent stated that it had then been observed 

 for three or four years, and it had been attributed in some measure to the 

 soil and culture. Fresh soil and manure were employed in the cultivation, 

 but the disease reappeared. We were assured that the only thing which 

 kept the disease in check was air, and to use no more moisture than was 

 absolutely necessary. 



This disease is said to be known in the United States, where the 

 Sclerotium has been called Sclerotinia Libcrtiana, and is closely allied to 

 the Sclerotium of the Potato haulms, and indeed apparently the same, as 

 it occurs also in other plants. 



Sacc. Syll. vii. 798 ; Mass. PL Dis. p. 150. 



Cucumber Black Mould. 



Dendryphium comosum (Wall). 



This common black mould has long been known as a saprophyte, 

 on decaying vegetable matter. Latterly it has been detected as a parasite 

 spreading from fragments of manure to the foliage of growing Cucumber 

 plants. Experiments have been made to discover some substance which 

 might be taken up by the roots of growing plants and render them 

 immune to the attack of fungus parasites. At present sulphate of 

 copper alone has proved effective. 



Joiim. B.H.S. xxviii. p. 142. 



Melon Bacteriosi>. 



Recently some important investigations have been made into the 

 causes of a peculiar form of Melon disease which is not uncommon in the 

 United States. We have grave doubts whether the same disease was not 

 present in this country in 1890, attacking Gourds and other Cucurbitaceous 

 plants. The attacked vines are said to have varied somewhat in their 

 appearance, but generally there was a decay of the stem, in proximity to 

 the root, and then the whole plant wilted and failed to grow. 



It is reported that an examination showed that the decomposing 

 tissues were teeming with bacteria. Inoculation of healthy plants was 

 made, and it was found that, with no other fungus present, the germs 

 obtained were abundantly able to introduce a rapid decay into Cucumbers, 

 Melons r and Squashes, Cucumbers being the favourite, and in them the 

 decay was most rapid, running through a four-inch fruit in a single day. 



The next step was the application of these germs to healthy plants 

 in the field. When the application was made near the end of a vine, the 

 latter rotted away in from three to four days. 



Numerous other experiments were performed, and all nearly equally 

 successful in demonstrating that the diseased virus may be communicated 

 by inoculation to healthy vines. 



Joum. B.H.S. 1891, xxvi. p. 540 (' Cucumber Wilt '), xxvii. p. cxcii. 



