THE WILT DISEASE OF PIGEON-PEA. 19 
Fusarium and Cephalosporium stages of the parasite strengthens 
this doubt. It has already been shown above that exactly similar 
stages are possessed by a fungus of another genus, the Nectria 
found on wilted pigeon-pea plants at Dehra Dun. It is indeed 
well known that it is scarcely possible to distinguish by the 
microscope alone, many of the members of the form-genus 
Fusarium from one another, and the same applies to an even oreater 
degree to the form-genus Cephalosporium. ' 
Both these form-genera are known to be in many cases lower 
stages of various genera of the Hypocreacez, and there are few 
groups amongst the fungi where it is more difficult to determine 
the genus by observation of conidial stages alone. In the present 
state of our knowledge it is not possible to refer a Fusarium or a 
Cephalosporium to its ascomycetal genus without actually deriving 
it in culture from the perithecial stage. This does not appear to 
have been done in the cultures with which successful inoculations 
of wilts have been carried out, and on this account the question of 
the parasitism of Neocosmospora cannot be regarded as settled. 
Wilt diseases, associated with the presence of Neocosmospora 
on the roots, have been found in the following crops in India :— 
Pigeon-pea, cotton, indigo, gram (Cicer arietinum), sunn-hemp (Cro- 
talaria juncea) and cow-pea (Vigna Catiang). Of these, cotton, 
indigo, and gram were selected for a further test of the parasitism 
of the fungus. In planning the experiments it was decided to try 
inoculations with the fungus from each of the three crops, and to 
add that from pigeon-pea in each series. 
Cotton Wilt. 
Cotton wilt has been reported from Sind, Gujarat, the Central 
Provinces and the Punjab in India. In the two latter areas it 
has caused considerable loss in the past few years. Perithecia of 
1 ¢, f. for Fusarium the synonyms given on page 50 of Smith and Swingle’s paper on 
the “ Dry rot” of Potatoes (Bibliography (15) ), and the remarks by Schikorra ( (14), p. 176) 
and for Cepbalosporium Brefeld’s Untersuchungen, Vol. X. Plates 1Y and V amongst others, 
