160 " Damping off" etc., of Tomato Seedlings 



described by Dastur 1 in India as attacking castor bean plants. Nearly 

 equal in importance is Phytophthora "B," probably Ph. cryptogea, which 

 has been described by Pethybridge and Lafferty 2 as producing a "foot 

 rot" of the tomato plant. In a few cases Rhizoctonia solani was the 

 causative organism. Samples of soil were then obtained from several 

 nurserymen and tested for their power to produce "damping off." 

 Throughout the whole of our experiments sterile seed-boxes (14" x 9" x 2"), 

 soil at the rate of five pounds per box, disease-free seed selected by 

 sifting, and sterile water were used. Seed-boxes were "made up" from 

 the soil samples and seeds were sown in the usual manner. Where 

 "damping off" occurred, one or more of the above mentioned fungi was 

 invariably found. 



Table I. 



No. of 



Preparation of infected soil to be tested. 



The naturally infected soil used for the whole of the experiments 

 described in this paper was obtained from a nursery where "damping 

 off" had been very destructive. The soil was placed under cover on a 

 flat surface and spread out in a layer of some six inches deep. It was 

 thoroughly broken up and mixed with a spade. Next it was divided into 

 eight small heaps and each heap thoroughly worked in turn. Heap 1 

 was then added to heap 2 and the combined heap well mixed. Heap 3 

 was then added to heaps 1 and 2 combined and so on until the whole 

 soil was worked into one heap. 



1 Dastur, J. F. Memrs. Dept. Agr. India, Bot. Series, vol. v, No. 4, 1913. 



2 Pethybridge, G. H. and Lafferty, H. A. Loc. cit. 



