loij MdlU'HOUX.V AM) rAKASlTlS.M iH' KlIIZOeTOMA. 



ExiHTunviit XI X. -Rliizinionia of luw poa on groiiiul nut- 



It is difficult to be certain from the results of this experiment 

 whether the Rliizorlonia of cow y)ea is really parasitic on ground 

 nut. In a fuither experiment the seeds were germinated under 

 conditions, which rendered chance infection practically impossible; 

 under these cii'cumstauces the appearance ot llic disease could only 

 result from deliberate inoculation or from the use of infected seed. 

 Five carefully .selected .seeds were sown on cotton-wool in sterile 

 drying towers containing Knops solution : all the seeds germinated, 

 i)Ut oidv tlii-ee produced healtln- voung seedlings. One oi these 

 was inoculated at the apex and also just below the cotyledon with 

 Iiliizoctonia of cow pea. This plant very soon died with an abundant 

 development of Rhizodoiiia in the infected areas (PI. ill. Fig. 1). 



The following table shows at a glaiu'c th(> infective powers of 

 the (liferent varieties of i'ltrjictoiuu. the nuinixTs ich'r to the per- 

 centage of inoculations which proved fatal - 



