DISEASES OF COFFEE 



227 



thecia on leaves which had been kept for some weeks in a moist 

 chamber, and, claiming to have produced typical spots by in- 

 fection with the ascospores, described the fungus as Sphcerostilhe 

 flavida. Fawcett in Porto Rico failed to secure infections with 

 the spores of a fungus corresponding to Massee's description. 

 More recently A. Maublanc and E. Rangel, working in Brazil, 

 have given a convincing account of experiments in which, by 

 keeping infested leaves in a very moist atmosphere, they obtained 

 an unbroken series of gradations between the form of fructi- 

 fication appearing in the field and a minute agaric (mushroom- 

 shaped fungus) with a bristle-like stalk and a membranaceous, 

 radially striated, hemispherical cap. They accordingly changed 

 the name of the parasite to Omphalia flavida. While it is de- 

 sirable that the observation should be repeated it would seem 

 that this name is at present entitled to stand. 



On the spots as they occur on the coffee plant the fungus 

 always has the same peculiar form of fructification, which is 

 to be regarded according to the last-mentioned authors as an 

 abortive one. It is, however, quite effective as a means of 

 reproduction, and may be viewed as an adaptation in some re- 

 spects superior to the ordinary methods of reproduction by spores. 

 The bodies referred to appear on the spots as slender yellow 

 stalks 1.5-2 mm. in height, terminated by a rounded head of 

 the same colour, the whole somewhat resembling a tiny pin. 

 Some writers have described the formation of conidia on the 

 surface of these heads, but no infection has ever been known to 

 be produced by them. WTiat does happen is that the heads 

 themselves, which are very loosely attached and somewhat 

 mucilaginous, drop off and adhere to the leaves or berries on 

 which they fall. When the surface is sufficiently moist a head 

 so lodged sends out numerous hyphae, which infect the underlying 

 tissue and give rise to a new spot. The heads retain their 

 germinating power for some weeks even after having been 

 dried, and so can be distributed with the fallen leaves. 



Control. 



The most obvious way of reducing the prevalence of the 

 disease is by increasing the access of sun and air to the trees, 

 but as in the similar case of cacao pod-rot it may not be possible 

 to carry this measure far without producing equal injury from 

 exposure. Picking off the affected leaves has been found to 

 exercise some control but can only be profitable where labour is 

 cheap. Spraying with Bordeaux mixture is quite effective 

 against the spread of the fungus, provided that the fungicide 

 can be made to adhere for a considerable time to the leaves. 

 In this connection the information elsewhere given regarding 

 adhesives should be consulted. The protection of the upper 

 surface of the leaves is the more important. No adequate 

 account of the use of lime-sulphur sprays has been seen. 



