Re3.(H(jter.)j4 



M the start of the experiment, the pots of 10" diameter were filled 

 from a mixed bulk of infested soil and were sunk into the ground to 

 prevent drying out. At the end of the experiment, the cyst counts 

 (not 'viable' cysts) from the pots containing resistant plants shovjcd 

 no increase over the unplanted controls (O), whereas the susceptible 

 plants caused increase in varying degrees. The cyst contents were 

 investigated by a squash technique, and there was evidence of a d';craase 

 in egg and larval counts for the pots containing resistant plants, and 

 large, but variable, increases for the pots containing susceptible plants 



Further batches of cysts were submitted to the action of a standard root 

 diffusate from S. tuberosum and produced the hatching curves shown in 

 Figure 2, 



Gladstone tubers 

 (19%) 



Figure 2 



Hatching tests on cysts after growing resistant plants. 

 Susceptible plants have produced cysts from which many larvae hatch. 

 Susceptiijle plants have apparently removed most hatchable larvae from cysts. 



