i88 DISEASES OF CULTIVATED PLANTS 



the bark. The injury is caused by a species of Nectria, 

 the mycelium of which fills the vessels of the wood, thus 

 preventing the passage of water upwards in the plant. 



No direct treatment is practicable, but as the fungus 

 exists in the soil, a longer system of rotation is suggested. 



The pepper vine wilt is considered to be in many 

 instances due to the injury caused by the same species 

 of Nectria that injures the pigeon-pea. In some instances 

 the pepper suffers from the presence of an eelworm 

 (Heterodera radicicola), but wilt occurs in many instances in 

 the absence of the eelworm, and even when the latter is 

 present, the fungus is also present, and is considered as the 

 primary source of disease. 



Cephalosporium and Fusarium forms of the Nectria have 

 been observed, but no diagnosis are given. 



Butler, Agric.Journ. of India, i, p. 25 (1906). 



Cacao pod blotch (Nectria Bainii, Massee) causes semi- 

 circular dark blotches on the pods, the diseased portions 

 becoming soft and watery. At a later stage the blotches 

 become covered with a velvety, interwoven layer of yellowish, 

 rust-coloured, or orange mycelium, which is studded over 

 with the minute, orange-red perithecia. 



Perithecia red or orange-red, woolly, becoming bald at the 

 apex, 300-350 (m diam. Asci cylindric-clavate, 8-spored. 

 Spores elliptic-oblong, ends subacute, i-septate, 10-12x5 /*. 



Massee, Kew Bulletin, Jan. and Feb., 1S99. 



Nectria ipomeae (I [alst.) in the Fusarium or conidial con- 

 dition causes a stem-rot of the egg-plant (Solatium melongena^ 

 L. ) and sweet potato (Ipomaea batatas ^ Poir.), covering the 

 withered stems with a white mould. At a later stage, 

 clusters of flesh-coloured perithelia appear. The disease 

 usually commences near the ground-line and extends both 

 into stem and root. 



Perithecia in little clusters, acutely papillate, squamulose, 

 red. A Fusarium stage is present. 



Nectria vandae (Wahrl.) is parasitic on the root of Vanda 

 suavis in cultivation. 



Perithecia solitary or in small clusters, pear-shaped, red, 

 scurfy, spores 8-10 x 4*5 /<. Conidia cylindrical, ends 



