PLANT DISEASES. 73 



University College of North Wales, Bangor. 

 Finger and Toe in Swedes. — This disease is widespread and 

 serious throughout North Wales. Carnarvonshire, the hill 

 districts of Denbighshire, and the portion of Anglesey bordering 

 the Menai Straits, suffer so heavily that in some localities swedes 

 are being omitted from the rotation. The extent of the loss 

 is shown by the fact that in many cases farmers cannot rely 

 upon Ufting more than 4-10 loads of roots per acre. AppHcation 

 of lime is usually impracticable, owing both to the initial cost 

 of the lime and the expense and difficulty of transport. Experi- 

 ments were therefore commenced with a view to testing the 

 relative susceptibihty of different varieties of swedes to finger 

 and toe, to find out whether any particular variety has special 

 powers of resistance to the disease. As a result, a Danish variety 

 has been found which possesses powers of resistance to a marked 

 extent. On the assumption that complete loss of crop can be 

 indicated by the figure 20, the intensity of attack in this variety 

 varies on the different plots from 2*4 to 4*9, as compared with 

 a British variety usually considered to be resistant to this disease, 

 which showed an intensity of attack varying from 5 • 8 to 9*2 on 

 the same plots. This Danish swede also shows considerable 

 resistance to the swede " Mildew," a troublesome disease in 

 dry seasons. The cropping power appears to leave little to be 

 desired. The crops from six varieties have been clamped 

 separately in order to compare the keeping qualities, and, in 

 addition, the feeding quality of each will be determined by 

 chemical analyses. The field work has been supplem anted by 

 laboratory investigations into certain aspects of the life history 

 of the organism which causes finger and toe. 



Bacterial Rots of Swedes and Turnips. — Very considerable 

 losses have been caused in the wetter parts of North Wales by 

 the rotting of roots in the field — in some cases 80 per cent, of the 

 crop has been destroyed. These " rots " have been the subject 

 of investigation for some time, and have been found to be due 

 to both fungi and bacteria. At least two different species of 

 bacteria are responsible; one reduces the swede or turnip to a 

 rotting mass within a fortnight from the beginning of the attack, 

 whereas the other attacks only the centre of the root, leaving the 

 rind and foliage healthy. The bacteria have been isolated and 

 have been found capable of reproducing the diseases on roots 

 in the laboratory. Investigations are being continued as to the 

 effects of time of sowing, soil conditions, and manurial treatment 

 upon the incidence of these root diseases. 



