38 SCALE PESTS OF COFFEE 



when carried of! by the rain and wind, lead to the infection 

 of healthy bugs. It is obvious that as the infection of this 

 pest depends in nature upon the chance dispersal of spores, 

 every effort should be made to assist nature by producing 

 the niost favourable conditions for spread and infection. 

 This subject will be discussed in detail when dealing with 

 combative measures. 



The Grey or Black FnngusiEmpusa lecanii, Zimm.). — 

 The grey fungus is usually not noticeable in coffee estates 

 during the South-West monsoon. However, during the 

 lighter North-East monsoon and throughout the early part 

 of the cold weather, it is commonly to be found attacking 

 green bug. Under favourable circumstances it may be 

 found active even up to May, and when this occurs it 

 furnishes a most efficient check to the increase of the pest. 

 The fact that it occurs chiefly during the drier portion of 

 the year has led planters to speak of it as the dry weather 

 fungus. This is hardly correct as it also requires a 

 certain amount of moisture in the air to develop and 

 spread. However, it can undoubtedly grow under much 

 less moist conditions than can the white fungus. The 

 early stages of attack are shown by a whitish discoloura- 

 tion of the bug, but later this changes to a dark grey, while 

 a gTeyish growth of fungus hyphae appears on the surface 

 of the bug. Some of these hyphae produce oval or egg- 

 shaped spores at their apices and by a mechanism charac- 

 teristic of the group to which this fungus belongs, these 

 spores can be shot off to distances of one or two inches. 

 This fungus is therefore not so dependent upon wind and 

 rain for dispersal as is the white fungus, and this un- 

 doubtedly accounts partly for its ability to spread during 

 drier seasons of the year. If the body of a bug attacked 

 by this fungus is cut open, a mass of dark brown spheri- 

 cal bodies are to be found inside. These are probably 

 spores of a more or less drought-resisting character which 

 help the fungus to tide over periods of drought. It is in- 

 teresting to note here that in Java, where both of these 

 fungi have been found, the white fungus appears to be 

 just as effective as it is in Mysore. On the other hand, 

 the grey fungus is looked upon as of minor importance 

 occurring sporadically. On many estates in Mysore, on 

 the other hand, the grey fungus is looked upon as a more 

 effective check than is the white one. What has been said 

 above with regard to the artificial spread of the white 

 fungus applies equally to this fungus also. 



