CH. 



48 DISEASES OF TROPICAL PLANTS 



Nectria theobromae on cacao. 

 jungeri 



Bainii 



camerunensis 



ditissima on cacao, coffee, tea, and rubber. 



striatospora 



coffeicola 



diversispora on cacao and rubber. 



funtumia on rubber. 



gigantospora 



ipomoeae on egg-plant and sweet potato. 



Closely related to the genus Nectria is the genus 

 Calonectria, containing C. flavida (Corda), Sacc., C. 

 cremea and (7. bahiensis, Hempel, all of which occur 

 on the cacao, and C. gigospora, Massee, which occurs 

 on the sugar cane. 



Another genus of this order is the Necosmospora, 

 which attacks water-melons, cotton, cow-peas, etc., in 

 the Southern United States, and which no doubt occurs 

 in tropical America. It has also been reported from 

 India (see pages 98, 108, 231, 237, 241). 



The fungus lives in the soil where it thrives sapro- 

 phytically on the decaying organic material. In all 

 probability it usually gains entrance to the host plant 

 through wounds on the roots, although many believe 

 that it can attack the healthy plants without difficulty. 

 It is most abundant in the tracheary tissues of the 

 xylem, but may also invade other tissues. It eventually 

 kills the plant, and then produces a growth on the 

 surface. Two types of conidia, micro-conidia and macro- 

 conidia, are produced. The perithecia are superficial, 

 scattered, flask-shaped, and often orange-coloured. The 

 asci are cylindrical, and each contains eight spherical 

 spores. Although this fungus as it occurs on the 

 different hosts has few, if any destinctive characters, 

 yet it seems impossible for it to pass from a host of one 

 species to a host of another species. This order also 

 includes the genus Sphaerostilbe, which contains S. 

 flamda, Massee, of the coffee. 



Epichloe is a genus the species of which occur on 



