■1920] DISEASES OF PLANTS. 549 



Another disease (iescribert is desipiated as sleepy disease. This is due to the 

 fungus Fusaiiuiii li/copersici. The disease appears ai)out the time the plants 

 are setting their last fruits. For control of this disea.se the authors recommend 

 the replacement of the soil in tlie l)eds with a new soil in which tomatoes have 

 not been recently grown or the sterilization of the old soil before the new 

 crop is transplanted. When the disease appears in the bed, destroying the 

 affected plants and sterilizing the soil with aimnoiiiacal copper carbonate solu- 

 tion are recommended. 



Notes are also given of stigmonose, wliich is attributed to the action of 

 aphids, and bacterial wilt which is cau.sed by Bacterium solanacearuin. For 

 tlie control of these disea.ses the use of nicotine sulphate for eradication of 

 apliids, and for the bacterial wilt care in transplanting plants so as not to 

 injure the roots, is advised. 



A disea.sed condition which is called white leaf curl is described, and in 

 certain stages is said to be similar to the leaf roll of potatoe.s. This disease 

 was particularly prevalent on tlie variety Lorillard grown in greenhouses. The 

 ttrst appearance of the disease is indicated in tlie upper part of the plant, where 

 the main leaves become affected. They present a grayish white color on the 

 upper and lower sides of the leaves as well as on the stem. The leaflets be- 

 come pointed or narrowed, giving something of the appearance of one of the 

 stages of mosaic. This disease is believed to spread in much the same way 

 as true mosaic, and is considered to be contagious. Methods of control are the 

 same as those practiced for mosaic, which include the handling of the plants 

 as little as possible, tlie careful removal of suckers, and control of white 

 fly, green ajiliis, and other evident carriers. 



Brief notes are given of edema of tomatoes, which is thought to be similar to 

 if not identical with that described by Atkinson (E. S. R., 5, p. 55). For the 

 prevention of this disease, control of the water .supply, ventilation, and heating 

 are recommended. 



Control of apple powdery mildew, D. F. Fisher (U. S. Dept. Agr., Farm- 

 ers' Bui. 1120 {11)20), pp. IJf, flgn. 8). — A popular account is given of the apple 

 powdery mildew (Podosphara leucotricha) , a serious disease of nursery stock 

 throughout the United .States, and al.so an important orchard disease in the 

 api)le growing districts west of the Ilocky Mountains, esiiecially in the I'acific 

 Coast States. 



I'\)r the control of the disease the use of lime sulphur or finely divided 

 sulphur is recommendt'd. In regions where burning is liable to follow the 

 apiilicartoii of lime sulphur or suliihur, later sprayings with Bordeaux mixture 

 are advised. 



Powdery niildow experiments, H. E. Watkrbuuy (Ann. Rpt. Dist. Jlort. 

 In.sp. Yahiiiia Count g. Wash., 1917, p. 1/9). — The conclusions drawn from these 

 exjierinients on powdery mildew are that the expense of a third spraying is 

 justified by the results in an orchard where infection is pronounced. Iron 

 sulpliid appears to be slightly more effective than atomic sulphur. Climatic 

 conditions in 11)17 were much le.«s favorable to mildew than in 191G. It is 

 thought that in a normal or almoriiially moist .season repeated sprayings would 

 be of greater value. 



The value of industrial fungicides in relation with mildew, S.\uzIcat 

 (I'rog. Agr. et Vit. {Ed. VE-st-Cevtrc), J,0 {1919), No. 20. pp. /,67, //G.S).— Com- 

 mercial fungicides are recommended as regards adiierence, simplicity of 

 preparation, and uniformity and relialiility as regards composition. 



Trunsniissibility of false mildew by seed, K. LAiiiKirr {(Utrtcnflora, 68 

 (1919), No. l.^-l.'i, pp. 175, 176). — Having raised the question in work previou.sly 



