292 DISEASES OF CROP-PLANTS 



Odontia spp. A white m5^celium, easily distinguishable from 

 that of Marasmius by its feathery pattern of growth and the 

 production of abundant stellate crystals of calcium oxalate, has 

 long been known as apparently capable of producing effects 

 similar to those of Marasmius. It has been commonly referred 

 to as the stellate crystal fungus, and, as a mycelium of unknown 

 affinities, was given the name Himantia stellifera by J. R. John- 

 ston. More recently E. A. Burt has described the fructifications 

 of Odontia Sacchari and 0. Saccharicola from Porto Rico material : 

 two closely related fungi which produce their spores on cane trash 

 in a close-lying, granular, buff-coloured layer hardly distinguish- 

 able without the aid of a lens from the surface of the dry trash 

 itself. 



The constant association and apparent organic connection of 

 Odontia fructifications with the typical stellate crystal mycelium 

 of Himantia suggests strongly that the two belong to the same 

 fungus, to which the name Odontia would in that case apply. 

 The relationship is highly probable but has not to the writer's 

 knowledge been proved by pure cultures. Both Odontia and 

 Himantia are generally distributed in these islands. 



Other fungi :— In Hawaii the stinkhorn fungus Ithyphallus 

 coralloides has been regarded as responsible for some amount of 

 root disease and in British Guiana the mycelium of the related 

 Phallus aurantiaciis is commonly vaet with. Forms of infesta- 

 tion with distinctive mycelia have occurred in Antigua but 

 without identification of the fungus concerned. 



C. W. Carpenter has shown recently that root decay, par- 

 ticularly of the Lahaina cane, in the Hawaiian Islands is caused by 

 Pythium hitler i Subram, which he considers to be responsible 

 also for wilt disease of the pineapple and a root-rot of rice. 



Symptoms. 



The prevalence in growing canes of the ordinary type of root 

 disease results in a backward and stunted condition of the stools. 

 The general effect is that of shortage of water brought about by 

 interference with absorption through reduction of the roots. 

 The leaves of affected shoots have their edges rolled inwards 

 when those of healthy plants are expanded ; they eventually 

 turn brown from their edges inward, and in order from below 

 upwards, until the shoot is withered to the top. The trash, 

 where it has not been stripped, is cemented firmly around the 

 lower joints of the canes, and under it matted roots occur up to a 

 foot or more from the ground, sent out in an endeavour to find the 

 necessary water. A clump infested early has a characteristic 

 stunted appearance and several or many of the shoots ma}^ be 

 dead and dry. Infested stools are easily turned over and exhibit 

 roots which are mostly either dead or lacking in fibrous branches 



It is not usual in this type of the disease for the stem bases 

 to be attacked, and the amount of injury to the roots is often 



