48 EXPERIMENT STATION llEt'ORD. 



Tbo swollen cells elongated, tinally rupturini,' the I'lddeniiis. .mkI tlic rlilontpbyll 

 granules lost their green color, beconiinu yellowish ami thially disappearing 

 entirely. 



A study as to the cause of this behavior showed that intumescences are pro- 

 duced on young potato plants from good tubers when transpiration is checked 

 and the roots are rapidly absorbing water. They are formed abundantly both in 

 l)rigbt light and in weak light, but they are not iiroduced in total darkness. 

 The abnormal state of turgescence of the bypertropbied cells is attributed to 

 the osmotic action of glucose, assimilated in part by the leaf, but principally 

 supplied to it from the underground tuber, which is richly provided with starch. 



Rind disease of the sugar cane, L. Lewton-Brain (Haicatian Siiyar I'Utiil- 

 ers' tita., Dlv. Path, and Physiol. Bui. 7, pp. J/'f, fiys. 16). — This bulletin, which 

 consists of an address delivered by the author before the Sugar Planters' As.so- 

 ciation, describes the rind disease of sugar cane and a number of related stem 

 diseases. 



The rind disease, which is due to MeIanconiu))i sacchari, is of considerable 

 importance and from the author's investigation seems to be a widely distributed 

 disease. The first symptoms of its occurrence have been noted in the leaves, 

 which dry up prematurely and turn yellow at the tips, the drying spreading until 

 the whole leaf is dead. The outer leaves are first affected, and the whole tij) 

 of the stalk ma.v become dry and dead, in which case attempts may be made to 

 develop some of the buds lower down. By the time the dying of the leaves 

 becomes noticeable other evidences of the disease are present. At this time if the 

 cane be split open it will be found that the nornially whitish color of tlie tissues 

 is changed to a bright or dark red or reddish brown. In the next stage the dis- 

 colored areas become sunken and lose their color, and later the interiiodes are 

 shrunken and more or less covered, with small, black, hair-like bodies. These are 

 the .spore masses which have been put out for the dissemination of the fungus. 



In experiments carried on by the author he has found that; the disease can be 

 spread by rotten cane, and under field conditions the fungus probably attains 

 access t-o the i)lant through wounds wbicli are often caused by leaf hoppers or 

 borers. 



In connection with this disease the author discusses the red rot of cane, due 

 to Colleiotricliioii faJcatmii. attention being drawn to this disease on account of 

 the desire for information and also to correct some ideas regarding the relation- 

 ship of the two fungi. The author claims that the rind disease and the red rot 

 are quite distinct, and tjie fungus causing the rind disease is considered to be a 

 wound parasite. However, if the vitality of the cane is lowered in an.v way, by 

 lack of cultivation, moisture, etc., it becomes liable to attack by this fungus. 

 The red rot is to be the subject of a future communication. 



A discussion is given of the relation between Mclaiiconiinn .'<a(chari and 

 Thielaviopsis ethaceticua, which causes the so-called pineapple disease of sugar 

 cane. These two fungi are often believed to be different stages of the same 

 fiuigus, but while inoculation experiments with Melanconium spores under 

 (ertain conditions result in the production of spores and a diseased condition 

 resemliling that due to Thielavioi)sis, the converse does not appear to have been 

 demonstrated. 



As practical suggestions for combating the rind disease the author recom- 

 mends the destruction of infected material, the prevention of wounds as far as 

 possible, the selection and disinfection of cuttings, cultivation so as to secure as 

 rapid growth as possible, and the use of resistant varieties. 



Some diseases of ginseng, II. II. Whetzki. (f^pec. Crops. ». set:, 6 {1907). 

 \o. '>7. pp. sc-'.X)). — In an address by the author an account is given of some of 



