PLATE VI 

 Phytophthora infestans: Infection of potato shoots and plantlets 



Fig. I. — This shoot grew from a diseased tuber planted in the greenhouse under 

 field conditions. Note the discoloration typical of P. infestans running up the stem. 



Fig. 2. — This shoot, which had not reached the stirface of the soil, grew from an 

 infected tuber in the field. 



Fig. 3. — This plantlet was the progeny of a diseased tuber planted in the open. 

 It should be compared with the shoot shown in Plate VI, fig. i, produced in the green- 

 house. The same symptoms developed in the field as obtained in the laboratory. 



