l62 



CHAPTER IX 



atris, in collum erectum, rigidum, 2-6 m.m. X 50, productis, ore subfimbriatis ; sporidiis 

 hyalinis, continuis, crasse lunulatis, utrinque acutis, 6- 5X3- 5, muco adiposo obvolutis. 

 Hab. in culmis sacchari officinarum India. 



Fig. 59 shows a cutting affected with this disease. The disease is not 

 of importance, and the mode of attack is similar to that described above. 



IhdU. 91 Gnomonia iliau (Lyon). Penthecia 325-480x240-310 

 microns in size, with beak about 350-550 microns ; asci clavate, thin- 

 walled, 60-80x14 microns, with a well-developed pore at apex ; spores 

 i -septate, hyaline, slightly curved, often slightly restricted at the septum. 

 Pycnidia 500700 microns in diam., thin- walled ; spores dark-brown, 

 elliptical to oval, coarsely granular, 7-10 x 15-28 microns. 



Figs. 60 and 61 show the spores and a section through the 

 perithecium of this fungus. This disease, which was first 

 described by Lyon in Hawaii and independently investigated 

 at the same time by Edgerton 60 in Louisiana, attacks the cane 

 in its early stages of growth. Under conditions favourable to 

 the fungus the stalks remain small and may die. If they recover 

 they may be structurally weakened, due to the poor development 

 of the basal portion, and are thus liable to damage by high winds. 

 The fungus, which manifests its presence by the appearance of 

 a white mycelium, is present on the leaf sheath and also pene- 

 trates to the interior of the stem. The disease is only reported 

 from Hawaii, where it is probably indigenous, and in Louisiana, 

 where it probably was imported from Hawaii. 



Root Diseases. The diseases which are mentioned in the following 

 paragraphs are not (with one exception) definitely associated with the root 

 system of the cane. They occur especially on the basal portion of the cane, 

 and also probably find a habitat in the soil. It is for these reasons that they 

 are frequently termed root diseases. 



Root Disease. 92 Dry Disease. Doknellan ziekte. Mara*mius sacchari 

 (Walskerf.Gregariavelbasifasciculata, diver sa, carnoso-membranacea persistentes ; pileus 

 albus late-camp anulatus deinsordide albus, planusvel cupuliformis, 15 m.m. diam. lamellae 

 albae simplices vel bifurcatae. Stipes centralis albus, long. 15 m.m. apice tubiforme, base 

 villosa. Hyphae albae. Sporidia hyalina, continua, irregulariter oblonga, utrinque 

 attenuata, 16-20 x 4-5. Hab. in caulibus vivis. 



The toadstool and the spores of this fungus, 

 both after Cobb, are shown in Figs. 62 and 63. 



This is one of the more serious cane diseases. 

 It was first observed in Java by Wakker, where 

 it is prominent in nurseries. In the West Indies 

 it appears on plantation cane. The disease is 

 characterized by the presence of a white mycelium 

 gluing the leaf sheath to the basal part of the 

 stem. The mycelial strands penetrate into the 

 ground and cause a decay of the roots, cutting 

 off the water supply and thus giving to the 

 cane the appearance of the results of drought. 

 The appearance of the toadstools is very un- 

 common. Johnston 93 states that in some cases they only appear in rainy 

 weather and sometimes only during the dry season. The disease has been 

 reported from Java, and generally through the West Indies. 



X550. 



FIG. 61 



