1922.] 



Potato Pink Kot. 



1127 



by Dr. G. H. Pethybridge in 1913.* About two years ago it was 

 detected in Scotland; and during the summer of 1921 outbreaks 

 were discovered at two centres in England. 



The fact that Pink Kot was discovered last season does not 

 necessarily imply that the disease then occurred in England for 

 the first time. It is certain that it is not present in the country 

 to any serious extent, but it is equally possible that the wilted 

 tops of plants affected by Pink Eot may have been mistaken for 

 the effects of Blight and that the rotted tubers may have been 

 regarded as due to Blackleg or bacterial decay as the result of 

 some form of mechanical injury. The discovery and prompt 

 identification of the disease is gratifying to this extent, that it 

 shows on the one hand the efficiency of the Ministry's Inspectors 

 in detecting new or rare diseases in the course of their manifold 

 duties, and on the other the keenness of farmers to be fully 

 informed and their wisdom in seeking expert assistance. 



The Disease in England. — In addition to the two field out- 

 breaks referred to, a case of Pink Kot detected in England 

 in seed potatoes may first be noted. Seed of the variety Majestic 

 obtained from Scotland was observed by Mr. V/. Buddin, the 

 Adviser in Mycology at University College, Beading, 

 to be showing suspicious symptoms. Laboratory examination 

 revealed the presence in the tubers of mycelium characteristic of 

 the group of the Phy corny cetes. The fungus was grown in arti- 

 ficial culture, isolated from other organisms, and was identified by 

 means of the characteristic and unusual resting spores as being 

 Phytophthora erythroseptica, the fungus causing Pink Kot. Only 

 a very few tubers were affected, the remainder of the balk being 

 perfectly sound. This was the first occasion on which the Pink 

 Kot fungus has been recognised in this country, and a potential 

 outbreak was averted. A notice as to the disease was circulated 

 to the advisers and inspectors, and various samples of suspicious 

 seed-tubers were subsequently submitted to the Ministry's Plant 

 Pathology Laboratory at Harpenden for expert examination ; but 

 these all proved to be suffering from frost or other non-parasitic 

 form of injury. 



The next report as to Pink Kot was received at the Laboratory 

 from Mr. J. Jarrett, an inspector stationed at Wellington, Salop, 

 who forwarded several samples of completely rotted tubers from 



* On- the Rotting of Potato Tubers by anew species of Phytophthora : Sci. 

 Proc. Roy. Dub. Soc, xiii (N.S.); 35,^ p. 529.). Further Observations on 

 Phythopihora erythroseptica, Pethyb.: Ib., xiv (N.S.) ; 10, p. 179. Also in 

 Journ. Dept. Agr. and Tech. Instr. for Ireland, Vol. XIII, No. 3, April, 1913. 

 Investigations on Potato Diseases (Fourth Report.) 



