Whittier, California, in August, 1915, Phytophthora terreetrla 

 isolated from the diseased bark of a citruB tree sufferinp from 

 mal di gomma at Palmetto, Florida, in January, 1914, Diplo dia 

 natal e ns is , isolated, by Mr. J. M. Rogers, from a citrus tree 

 in the Isle of Pines, W. I., and received by the writer in the 

 fall of 1913, and Phoinopsis citri received from H. E. Stevens 

 from Florida, in October, 1916. All four fun^i had Veen cul- 

 tivated in tubes of ccrn-meal apar in darkness at 15 to 20° c. 



since the original material was received by the author. 

 Durinr that time transfers to new tubes of media ^ad been made 



at intervals of about six or eight weeks- These cultures 

 will be known as the primary stock cultures. 



THE EXPERIMENTAL CULTURES 

 Approximately five days before the starting of each 

 series of experiments several secondary stock cultures of 

 each funpus were started ~ry transferring small bits of medium 

 containing mycelium from a primary stock culture to the center 



of the new agar plate. These secondary stock cultures were 

 kept In darkness with a temperature of about 20°C for a>out 

 five days previous to the making of the experimental cultures. 

 Little plugs or disks were cut out of the agar plate just back 

 of the advancing margin of the circular growth area of one of 

 t'oese five-day secondary stock cultures. The disks were 

 2.5 mm. in diameter and about 1.5 mm. tnick. They were cut 



out y-y means of a cylindrical platinum cutting device like 



vn,. Each disk was lifted on the 

 that described ~ry KeittV^ 



V^Keitt, G. II. , Simple technique for isolating single spore 

 strains of certain types of fungi. Phytopathology. 5,2o6- 

 1913. 





