THE WILT DISEASE OF PIGEON-PEA. 4] 
= 
No. of plants. Treatment. Date of inocula. | Result. 
|- 
tion. Remarks. 
About 5 plants out | Inoculated with) Inoculated 1-7-08. | Wilt appeared. | The first death 
of a clump of| Cephalosporium was on 29-7-08, 
about a dozen| from pigeon-pea. All i 
which had been a elu af - de 
year previously dead by the 
inoculated with end of the 
Neocosmospora. | year. 
The same ina Ditto. Ditto. Ditto. The first death 
clump not previ- was on 24-7-08. 
ously inoculated. | All were dead 
| 
| 
| by November, 
08. 
The disease spread from the moculated clumps to those belong- 
ing to pots 2, 4, 6, 8, 9, 10, 11 and 12 of Series V, all of which were 
near together and not separated by any obstacle from the inoculat- 
ed clumps, and were perfectly healthy at the time of inoculation. 
Hence, though the plants from pot 3 had flourished for more than 
a year alter bemg inoculated with Neocosmospora, they succumbed 
without exception to the attack of the Cephalosporium in from one 
to five months, though they were very large plants, mostly over 8 
feet high. 
The proof is therefore complete that the Cephalosporium 
isolated from the roots of wilted pigeon-pea plants in the manner 
described under Series XIV above, is a virulent parasite and that 
it, and not Neocosmospora, is the cause of the wilt disease 
commonly found in this crop. 
Series XVIII. 
An experiment was carried out to test whether the presence of 
Neocosmospora in any way altered the course of the disease in- 
duced by the Cephalosporium isolated from the interior of wilted 
pigeon-pea roots. 
The culture of the Cephalosporium used was a subculture on 
steamed potato from that used in Series XIV. That of Neocosmos- 
pora was an agar subculture originating from the culture on pigeon- 
pea used to inoculate pot 2 of Series V above. 
