286 



THE AGRICULTURAL NEWS 



September 3, 1910. 



FUNGUS NOTES. 



TWO INTERESTING FUNGI IN 

 ST. LUCIA. 



A short time ago, two specimens of fungi were forward- 

 ed to the Head Office by Mr. .J. C. Moore, Agricultural Superin- 

 tendent in St. Lucia. The first occurred on a piece of guava 

 stem, and in its general a.ppearance was similar to the pink 

 disease of cacao. The guava stick was being used to sup- 

 port a cacao branch, but no pink disease was observed on that 

 tree, though it was evident on another one some little 

 distance away. The fungus formed smooth, pinkish or buti'- 

 coloured patches, spreading all over the bark of the host. 

 These patches consisted of closely woven hyphae very 

 firmly adpressed to the surface upon which they were grow- 

 ing. As it seemed possible that the fungus might attack 

 cacao, or might even be the same as Corticium lilacino- 

 fnscum, B. and C. [formerly known, owing to inadvert- 

 ence, in the publications of this Department, as 'Cortici- 

 um lilaco-fu.scum'], which is responsible for pink disease, 

 a portion of the specimen was sent to Kew, where it was 

 identified as Cortiriuin laeve, Fr. This fungus is a common 

 saprophyte on dead pieces of the wood and bark of several 

 trees in ]ingland, and occurs in North America, the West 

 and East Indies, and Australia, as well as in Europe. It 

 does not seem altogether impos.sible that it might attack 

 cacao parasitically, just as Corticium lilacino-fuscuin does, 

 in which case the treatment recommended against the latter 

 fungus would be found effective in the case of the former 

 The treatment referred to will be found fully described in the 

 Aijrindtural Xews, Vol. VII, p. 237, and need not be given 

 here. It suffices to add that, according to Mr. Moore, it is 

 proving successful in the case of the cacao tree already men- 

 tioned as being attacked by the pink disease. 



Two or tliree other species of this genus are known t'> 

 attack many different economic host plants in various parts 

 of the tropical world. Since this is the case, a somewhat 

 more general account of the group may be found of interest. 

 The genus Corticium belongs to the family Thelephoraceae 

 of the Hymenomyceti)ieae. (See A(/i-iru/fnral JW'ws, Vol. IX, 

 pp. 158, 159 and 190.) The members of the genus have 

 a wa.xy or Heshy .superficial fructification, closely adpressed to 

 the substratum, and varying in colour from nearly white to 

 buff, pink, or rose-red; in .some species the margin of the 

 fructification is somewhat rolled back. The spores are colour- 

 less, and are borne on typical basidia These latter are produced 

 closely packed together at right angles to the .surface of the 

 patch. The spores are thus formed freely in the air, and 

 can be distributed by wind or other agencies. One species of 

 this genus, Ccrtu-iumjaraiiiciim, Zimm., is reported by Petch 

 as occurring on Hevea, tea. Cinchona, orange and plum in 

 Ceylon. {Circulars and Aijricullural Journal of the Royal 

 Jlotanic Gardens, Ceylon, A'ol. IV, No. 21.) On rubber it 

 usually originates at the fork of a tree, or where several 

 branches arise together from the main stem. The hyphae 

 can gradually penetrate the bark and cause it to die, 

 and split off. The wood is scarcely attacked at all. The 

 fungus can be removed at an early stage without injury to 

 the bark, merely by scraping; but later, it completely covers 

 the circumference of the tree, and the bases of the adjacent 

 branches. Young stems about two years old are rajjidly ringed 

 and killed, .so that the effect of "the fungus is to kill the 

 small lateral branches, and to cause. portions of the bark of 

 the main stem and the larger ones to split off. Young 

 trees should be cut back below the affected part; in the 

 case of older trees which are not badly attacked, the 



diseased bark should be cut out, and the wound tarred. In 

 advanced cases of the attack on older trees, the stem must be 

 cut back as in the case of the younger plants. On tea, the 

 fungus begins by forming pink incrustations on the younger 

 branches, which lose their leaves and die back. From Fetch's 

 account, the disease of Hevea and tea in Ceylon appears to be 

 of a more serious nature than that of cacao in the West Indies. 

 In Java, Zimmermann and others have found Corticium 

 javanicuni, on coffee, ramie, caca3, Cinchona, nutmeg, tea, 

 Eriodendron, pepper, coca, cinnamon. Cola, Castilloa, Hevea, 

 dadap, annatto {Bi.ca Orellawt), mango and many trees and 

 shrubs of minor im[iortance. It occurs on Hevea in Southern 

 India, and is probably the species that is found on ramie and 

 Strobilanthes in the Strait Settlements, according to Ridley. 

 Another, Corticium calceum, Fr., has been reported from the 

 Federated Malay States as causing injury to Hevea almost 

 identical with that in Ceylon. {Ayricidtnral Bulletin of the 

 Straits and Federated Malay States, Vols. Ill, p. 173; 

 IV, p. 423; V, p. 69.) Petch .suggests that the identification 

 of the fungus in the Federated Malay States is possibly 

 incorrect. Lastly, there is another .species somewhat differ- 

 ent in appearance, which causes thread blights in Java. This 

 is Corticium theae, Bern, which was described in the Agri- 

 cultural News, Vol. IX, p. 206, so that no further description 

 need be given here. To summarize, the species of this genus 

 occur as parasites on many plants, including .such important 

 economic trees as mango, nutmeg, tea, coffee, cacao and 

 rubber, and have been found in the West Indie.s, Java, 

 Ceylon, Southern India and the Federated Malay States. 



The other fungus mentioned at the beginning of this 

 article was also forwarded by Mr. Moore. It was growin" 

 on branches of lime, and, according to the information 

 received, is frequently associated with the death of the parts 

 affected. This one may be observed wherever limes are 

 grown in St. Lucia. It forms superficial, violet grey, waxy 

 patches, often completely encircling the branch and covering it 

 for con.?iderable distances. It is very easily detachable and, 

 when removed, is seen to be of a dark-brown colour on the 

 surface nest to the substratum. It may be mentioned further 

 that a moderate number of scale insects, particularly the 

 purple scale (Afytilaspis citricola), and the green scale 

 (Lec'iniu)n viride), apparently in a perfectly healthy condi- 

 tion, may be found on the surface of the branches beneath 

 the fungus. 



The specimen was identified at Kew as Thelephora 

 pedicellata, Schwein.; the genus is related to Corticium and 

 included in the same family. Galloway, in the Journal of 

 Mycology, Vol. VI, p. 113, states that it occurs on pear 

 branches in Alabama, on oak ((Juercus cocinnea) in New 

 Jersey, on Palmetto {Sal/al Palmetto) in Florida, and on 

 apple trees in Te.xas. On all these, it is capable of doing 

 damage, but will yield readily to treatment. Galloway sug- 

 gested cutting out all the diseased wood, washing the wounds 

 with a saturated solution of iron sulphate, and covering 

 them with shellac or grafting wax. This treatment seems to 

 be rather unnecessarily drastic; probably the following would 

 be found effective. Remove and burn all dead branches, and 

 tar the cut ends; in the case of living branches, paint the 

 parts attacked with the lime-sulphur mixture recommended 

 for pink disease of cacao. (For reference see above.) This 

 should be all that is necessary, as the fungus does not apjjear 

 to penetrate the host to any serious extent, and may only 

 kill the affected parts by suffocating them. The disease does 

 not seem to be of a very serious nature, as, though appar- 

 ently fairly wide-spread, it should yield very rapidly to treat- 

 ment, more especially on account of its very superficial 

 character. 



