MAY 9 - 1910 
THE WILT DISEASE OF PIGEON-PEA 
AND 
THE PARASITISM OF NEOCOSMOSPORA VASINFECTA SMITH. 
BY 
i. J. BUTLER, MB, F.L.S., 
Imperial Mycologist. 
CHAPTER I. 
THE PIGEON-PEA NECTRIA. 
Ly 1906 the writer (1) ' described diseases of pigeon-pea (Cajanus 
indicus) and black pepper in India, with all the characters of the 
large group of wilt diseases induced by parasites of the genus 
Fusarium, which have recently attracted the attention of mycolo- 
gists in many parts of the world. 
The symptoms on pigeon-pea were such as would arise from a 
total or partial stoppage of the water-supply from the roots to the 
aerial parts of the plant. The result was a “ wilting” or withering, 
more or less sudden according to the degree to which the root 
system was involved, and the intensity of transpiration at the 
time. The xylem vessels of the root were in all cases found to be 
plugged by masses of hyphe, offshoots from which extended into 
the parenchyma of the central cylinder and into the cortex. On short 
simple branches within the larger vessels smal] elliptical spores 
were found budded off apically ; pure cultures obtained from these 
proved them to belong to the form-genus Cephalosporium. Within 
the vessels were also sometimes found special durable thick-walled 
cells (chlamydospores) attached to the hyphe in various ways 
and capable of germinating on being sown in water. 
1 These numbers refer to the bibliography at the end of the present paper. 
