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at home, but in all parts of the earth, for the protection, present 

 and future, of American agriculture. 



A great industry like rubber growing representing investments 

 of millions of pounds should be adequately protected. This means 

 thorough and timely investigation of every possible prime factor 

 and every related subsidiary factor touching the growing of rubber. 

 It also means the employment of a large force of active and highly 

 trained specialists and the establishment of numerous well equipped 

 laboratories. The Hawaiian Sugar Planters have profited exten- 

 sively by such an organization. The American Eubber Company in 

 Si;matra evidently intends to do so. 



The investigation of rubber diseases has usually proceeded by 

 certain stereotyped methods. From diseased tissue, pure cultures 

 are started in artificial media, the resulting growths inoculated 

 into healthy tissue and the disease reproduced. The vegetative 

 form at least of the specific organism is thus isolated, and then 

 attempts are made to secure the spore bearing form in pure culture, 

 to determine its identity and to determine the original sources and 

 methods of infection. Unless all of this can be accomplished it 

 frequently follows that effective sanitary and remedial measures- 

 are impossible to devise. Many fungi refuse to produce their spore- 

 bearing forms in any ordinary artificial culture. However, all of 

 these fungi will fructify freely under certain natural conditions. 

 The perfect form of a certain serious apple disease was not known 

 until finally discovered on small withered and weathered apple- 

 mummies that lay on the ground beneath the tree. Numbers of 

 other important cases of the sort might be cited. 



It follows, therefore, that there is another important avenue 

 through which these problems should be approached, and which is- 

 usually largely neglected. Every fungus growing on or in connec- 

 tion with rubber trees should be I'liown and its relation to this 

 important crop thoroughly understood. It is commonly the case 

 that parasitic fungi produce spore bearing forms only after the 

 affected tissues are dead and then, frequently, only under certain 

 natural conditions. It follows that every fungus fruiting on dead 

 Hevea must become an object for investigation. It is not safe tcv 

 overlook one ! C^ertain forms formerly supposed to be exclusively 

 saprophytes, living only on dead tissue, have been found, under 

 certain circumstances to be actively parasitic. This is true of even 

 such a common saprophyte as Polyporus hirsutus Pers. Trametes 

 badia Bk. may be purely saprophytic, l)ut I found it in the Botanic 

 Gardens, Singapore, on Saraca declinata with its mycelium pene- 

 trating living tissue. The life histories of every fungus appearing 

 on Hevea — living or dead, should be clearly traced. From every 

 fungus producing spores on dead tissue, inoculations should be 

 made into living tissue, and in many cases they will be found to 

 take hold with definite parasitic action. If all were included I 

 "have no doubt tliat the identity of various obscure fungus diseases 

 would be determined by this indirect method, where other methods 

 had failed. T also have no doubt but that it would bring to light 



