PHYTOPATHOLOGY IN THE TROPICS 



JOHANNA WESTERDIJK 

 Director of the Phytopathological Laboratory, Amsterdam, Holland 



Tropical life is a luxurious life 



Nowhere does plant and 



animal life show itself in such variety and abundance 



the equator. 



As the conditions in those regions are uncommonly fa\ 

 able to plant growth, it would appear that the plant parasites 

 also have a good chance of living. In several tropical coun- 

 tries plant diseases have been studied in a more or less ex- 

 tensive way, but the general features of plant diseases in the 

 tropics, unlike those of the temperate regions, have hardly 

 been touched. I have been for some time studying plant 

 diseases in our colonies of the East Indies, the so-called 

 Malayan Archipelago, and I wish to give you some general 



impressions on fungous diseases in those countries, 

 remarks can be onlv suggestions, as thorough investig 



My 



far as I know 



on these tropical problems have never, so 



been made. 



The Malayan Isles have an average temperature of 30° C 

 in the lower parts, accompanied by a humidity of 80-100 

 per cent. The climate is a monsoon climate. In the time of 

 the wet season it pours every afternoon, but in the dry time 

 the rains are verv scarce in the lowlands but not infrequent 



forest-covered mountain 



One would be inclined 



think that this 



combination of 



high temperature and moisture would be extremely favorable 

 for fungous growth, and that therefore fungous diseases 

 would play a large part in the culture of economic plants. 

 This, however, is not the case. We find that insect troubles 

 prevail, and that, compared with our temperate regions, few 

 diseases exist. We would not conclude these facts from the 

 literature, as a large number of diseases caused by fungi 

 have been described. But in visiting the countries it struck 

 me that only a few diseases are of real importance; a great 



Ann. Mo. Bot. Gard., Vol. 2, 1915 



(307) 



