50 SCALE PESTS OF COFFEE 



estates or parts of estates where they are not present, 

 branches containing bugs killed by them should be cut 

 and tied on to trees on which they do not occur. Cultures 

 of the white fungus made in the departmental laboratory 

 have been dissolved in water and then sprayed on plants 

 in different parts of the estates and the infection has been 

 successfully introduced. Such a measure will not be 

 necessary in most cases as there are very few estates 

 attacked by green bug, from which this fungus is entirely 

 absent. 



To furnish favourable conditions for these fungi, it 

 appears necessary to increase and conserve the moisture 

 in the air as far as possible. Both the fungi require a 

 certain amount of humidity though they vary in this 

 regard. While, in Mysore, the white form is regular and 

 wide-spread and requires little attention beyond what has 

 been recommended above, the black form appears to be 

 more sensitive to variations in humidity. In the same 

 estate, while it is present on trees under thick shade, a 

 few feet away, in more open situations it will not be found. 

 So, too, a slight failure in the North-East monsoon all but 

 prevents its appearance. The fungus appears at a criti- 

 cal time when the bugs are reviving after the destruction 

 caused by the white fungus during the South-West mon- 

 soon and its ability to keep them in check depends on a 

 sufficiency of moisture. It might be possible by so regu- 

 lating and improving the shade and by the prevention of 

 too rapid evaporation to produce more favourable condi- 

 tions for this fungus. The recommendation applies 

 especially to those estates which are unfavourably situated 

 with regard to the North-East monsoon or where shade 

 and slope are such as to facilitate rapid evaporation. In 

 these estates the replacement of such trees as silver oaks 

 by those yielding greater shade might possibly diminish 

 the virulence of the pest by increasing the efficiency of 

 the fungi. Whether it is possible to regulate the shade 

 so as to offer favourable conditions for the development 

 of the black fungus and at the same time not to affect 

 seriously the yield of coffee, is a question well worth the 

 consideration of those planters who have been seriously 

 troubled with the pest. 



