252 



COLOCASIA BLIGHT. 



is ample to allow of infection. Leaf inoculations were always done 

 on both surfaces. The wounding, except where otherwise stated, 

 consisted in scraping away the epidermis with a sterile knife. 

 Controls were kept in every case, those of potato being previously 

 wounded on the leaves, the rest unwounded. These were placed 

 as nearly as possible under the same conditions as the inoculated 

 plants, well watered on the green parts and covered by bell jars. 

 All the inoculations in this table were done at laboratory temper- 

 atures, which ranged from about 25° to 30° at the time. At the 

 latter temperature the sporangia were sown in cooled water to 

 secure zoospore emission, which does not take place freely at tem- 

 peratures approaching 30°C. (see p. 241). 



Inoculations with Phytophthora Colocasice Roc. 



