233 



A NOTE ON THE OCCURRENCE OF APHELENCHUS 



PHYLLOPHAGUS IN CHRYSANTHEMUMS IN THE 



TRANSVAAL, WITH SUGGESTIONS FOR ITS 



CONTROL.. 



BY 



J. Sandground, M.Sc, 



Lecturer in Zoology, University of the Wiiwatersrand, 

 Joliannesbury. 



Bead July 10, 1922. 



The following note has for its pui-pose the recoi'ding of the 

 presence in the Transvaal of Aplielenchus phyllophagus, a msilig- 

 iiant pest which, when well established, may seriously menace the 

 culture of chrysanthemums. 



The parasite, a nematode, was recorded for the first time 

 in England by F. H. Stewart during 1921, and is apparently 

 not unknown in other parts of Europe. Its presence in South 

 Afnc^i was brought to my notice by a sample of diseased leaves 

 kindh' foi-warded to me by Mr. Haines, of the Division of Ento- 

 mology, Pretoria, who had received the specimens for investiga- 

 tion from Mr. A. J. Atkin, of Parktown, Johannesburg. Mr. 

 Atkin has infoiTned me that for two seasons his chi*ysanthemums 

 have suffered from a wilting disease, which reached its clima;x 

 when the plant was nearly full grown, and effectively retarded 

 the development of the flower bvxcls. I have since found infected 

 Infants in other suburbs of Johannesburg, where, on making 

 inquirieis, I was informed that, in the opinion of the grower, the 

 plants were infected with mildew or rust, the symptoms of which 

 diseases closely resemble those produced by ApJielencMis. The 

 parasite has no doubt been introduced into this country by 

 " slips " or cuttings from Europe, and is apparently of relatively 

 long standing. 



The morphology and biology of Aphclenchus phtjllophagus, the 

 parasite here concerned, have been very adequately described by 

 Stewart. (Parasitology, XIII, pp. 166-179), and it is therefore 

 deemed unnecessary to discuss this question further than to state 

 that Aphelcnchus belongs to a group of plant parasitic nematodes 

 which are of no mean economic importance in consequence of 

 their depredations to agricultural and horticultural crops. There are 

 three genera of nematodes chiefly involved in this parasitic role, 

 namely, Hcterodera, Tylenchns, and Aphelenchvs. Heterodera 

 is easily distinguished from the latter two parasites on account 



