1919] W8EASBS OP PLANTS. 847 



■tderation especially of the so-called degeneration diseases of potatoes and of 

 the problems of certification of seed potatoes. Projects were organised In con- 

 nection with potato mosaic, loaf roll, and curly dwarf. Reports onder ti. 

 heads wen- presented and discussed, and a project committee was appointed 

 to take charge of the various problems connected with the certificate i ed 



potatoes. 



Some serious potato diseases, S. L. Bastin (Jour, liuth nn<l West and South. 

 Counties soc, 5. ter., t£ (1917-18), pp. 88-106, pis. .'. I . The author di 

 with appropriate control measures locally Importanl potato diseases, Including 

 late blight (Phytophthora infestatu), potato scab {Aetinotnifeea ehromogem 

 cork; or powdery scab (Bpongospora suoterraneo), wan disease or black seaJb 

 (Bynehytrium endobiotioutn) and other scab diseases, stalk disease ( Sclera tinia 



SOii ■mtiuruiii), Botrytis disease (It. cinvrni), and blackleg Or black stein r»t 

 (Bacillus phytophthortu I. 



Observations on obscure potato troubles, II. T. G&SBOW (Phytopathology, 8 

 (1918), No. 9, pp. 491-495, figs. J f ). — Descriptions are given of attacks of ll< t- 

 erodera radicicola on the potato tuber, the effect of unfavorable Btorage condi- 

 tions, leaf streak, and mosaic disease. The last disease the author claims 

 to have successfully transferred by inarching diseased plants with vigorous 

 ones, the resulting tubers having produced typical mosaic disease. 



Seed tuber treatments for potatoes, G. H. Coons (Phytopathology, 8 (IB 

 JYo. 9, pp. 457-468, figs. 6). — The value of seed tuber disinfection for the preven- 

 tion of scab and Rhizoctonia having been Questioned, the author conducted a 

 series of experiments to determine, if possible, improvements in the method of 

 seed treatment, as well as to test the whole matter of the desirabiliy of treat- 

 ments. 



Clean, scabby, and scurfed potatoes were treated in various ways with for- 

 maldehyde, corrosive sublimate, and bleaching powder. It was found that 

 the formaldehyde used in dilute solution for either soaking or sprinkling the 

 tubers, together with planting in clean ground, was efficient In reducing the 

 amount of scab, and the soaking of the tubers for 1J hours in a 1 : Jin solu- 

 tion controlled to a slight extent the attack of Rhizoctonia. Corrosive subli- 

 mate 1:1,000, in which the tubers were soaked for * hour to 1$ hours, con- 

 trolled both scab and black scurf. When the solution was heated to ."4° C. 

 (120.2° F.), with a treatment of 5 minutes' duration, efficient control of scab 

 and black scurf was obtained. Prolonged treatment with corrosive sublimate 

 or treatment with hot corrosive sublimate resulted in pour stands. Bleach- 

 ing powder (5 per cent solution) had no bad effect on the stand and but 

 little beneficial effect in controlling scab. It was not tested against Bhi) 

 tonia. 



The experiments conducted by the author seem to show that tho important 

 ^source of both Rhizoctonia and scab is Infected seed, the soil fu rni s hin g a 

 negligible amount of infectious material. Tins conclusion is held to apply for 

 the present only to the conditions under which the experiments were con- 

 ducted. 



Fusarium blight of potatoes under irrigation. H. <;. M \cMii i w (Jour. Anr. 

 Research [U. S.], 16 (1919). No, 11. pp. 279-30.',. pit. 5). An account la given 

 of an investigation of Fusarium blight of potatoes conducted by the Bureau of 

 Plant Industry, U. S. Department of Agriculture, in Colorado, where con- 

 siderable losses are reported as due to Fusarium blight Tin ral stftj 

 of blight are recognized; first, a Btage in which decay and death of t' 

 piece and the new plant occur before the new shoot emerges from the ground : 

 second, a later stage in which the young plant shows many s ym p tom s of in- 



