190 



THE AGRICULTURAL NEWS. 



Junk 10, 1911. 



FUNGUS NOTES. 



MISCELLANEOUS FUNGI FOUND 

 RECENTLY. 



It is proposed in the following article to deal with certain 

 miscellaneous fungi which have Leen found in some of the 

 West Indian Islands mainly during the last few months. Of 

 such miscellaneous fungi, those parasitic on plants are not at 

 present of any serious importance but are recorded as being 

 of local interest and possibly worth watching in case they 

 should show a tendency to spread at a later date. 



I'RUiT SPOT OF MANGO. The fruits of a large mango 

 tree growing in the Botanic Garden, St. Vinc&"t, were observ- 

 ed to be affected by a disease which took the form of small 

 dark-brown or nearly black circular spots about | inch in 

 diameter. They occurred on fruit of all ages, from that 

 just formed to that which was half-grown or nearly fully 

 grown. When the diseased fruits were kept, the spots extend- 

 ed largely and ran into one another, forming discoloured 

 areas nearly i-inch across. ."Vt the same time, the tissues 

 became sniikeii, over the infected portion, and numerous very 

 small pink or yellowish pustules appeared all over the surface. 

 These burst through the epidermis of the fruit, and consisted 

 of the spores of a species of Gloeosporium, which was most 

 probably 6-'. manrjiferae, and may be regarded as the cause of 

 the disease. The members of this genus, and of the closely 

 allied Colletotrichum, cause anthracnose and spotting of many 

 fruits, and are responsible for diseases of several kinds. In 

 addition to the spots on the fruits, a dying back of the fruit 

 stalk__was often observed, which is probably attributable to the 

 same fungus. 



lA'.KV SPOT OF PtiNGAL BEANS. A sliort time ago sj)eci- 

 mens of the leaves of the Bengal bean {Stizolohium 'itcr/imum) 

 were forwarded from Grenada for examination at the Head 

 Office. These showed the presence of fairly numerous spots, 

 approximately circular in shape and 2-4 mm. in diam- 

 eter. The centre of each spot was occupied by colourless 

 semi-transparent tissue, and was surrounded by a broad band 

 of dry tissue of a bght-brown colour; the whole spot was 

 enclosed by a dark-brown ring dividing it from the healthy 

 green portion of the leaf. The spots were mostly separate, 

 but occasionally two or three, or even more, would run into 

 one another. The disease was caused by a species of Cercos- 

 pora, the conidiophores of which appeared in tufts in the 

 central white portion of the spots. They were to be found 

 on both sides of the leaf, but were connnonest on the under 

 surface. Leaf spots of this nature are common on manj' 

 weeds in the West Indies, and there is always a reasonable 

 po.ssibility that the same fungus as attacks the Bengal bean 

 may have other host plants. 



GUINEA coi!N iiitsT. A short time ago, specimens of the 

 well known rust on Guinea corn leaves were forwarded to 

 Kew and identified as Puccinca purpurea, Cke. — a rust 

 common on Sorghums in North America and the 

 West Indies, and also found on Indian corn. Only 

 the uredospores and teleutO".pores are known, though it is 

 possible that an aecidial stage occurs on some other host 

 plant. The affected spots on the Guinea corn leaves showed 

 the presence of small black pycnidia, in addition to the rust 

 fungus. These pycnidia contained hyaline biccllular spores, 



spindle-shaped and having small appendages at their ends. 

 They belong to a fungus identified at Kew as Darluca Jilum, 

 (Bivon), Cast., which is a well-known parasite on several of 

 the rust fungi. Another species of rust fungus, also reported 

 as occurring on Guinea corn in the West Indies, is 

 Puccinia sorijlil, Schw., which is supposed to be a native of 

 America and an original parasite on Indian corn. The com- 

 plete life-cycle of this fungus is known, as its aecidial stage 

 has been found to occur on Oxalis and to be identical with 

 Aecidium oxaiidis, Thiim. 



ENTOMOGENOu.s FL'NGi. An intersiiug fungus has recent- 

 ly been found on the leaves of trees of mango and star 

 apple (Chrys(iphyllu)ii Cainito) in Dominica, antl on those 

 of Java plum {Euyenia Jamdo/ana) in St. Lucia. It 

 forms small, light pink masses or stromata from which 

 .several small spherical bodies project. These are closed 

 at first, but later on extrude short cone-shaped, rose- 

 coloured masses of spores. Later still, the spheres open out 

 into shallow cups, lined with the rose-coloured masses of 

 spores. The spores themselves are borne on short conidio- 

 phores, lining the cavities of simple or branching pycnidia 

 sunk in the bottom of the cups. Each spore is hyaline when 

 seen by itself, and colourless, and is pointed at either 

 end. This fungus was identified at Kew as the conidial 

 (Ascbersonia) stage of Il)/j>ochrella o.>\i/spora, Massee. Its 

 method of occurrence on the leaves in St. Lucia, which were 

 examined in the fresh state, as well as the fact that the leaves 

 did not appear to be much diseased, suggested that it was 

 a parasite on some scale insect, possibly the mango shield 

 scale (Coccus mangiferae), which was found on the leaves. 

 This hypothesis is borne out by its systematic position. Two 

 species of Aschersonia, to which genus its conidial form 

 belongs, arc well-known parasites of scale insects and white 

 fly in Florida, while several species of Hypochrella occur on 

 scale insects in Ceylon and Java. It is probable, therefore, 

 that another useful parasite of scale insects has been added 

 to the list of those already known (see A'/ricu/tiira/ ]\'e^vs 

 Vol. VIII, pp. 299 and 411). 



An unidentified mycelium, of cottony consistencj' and 

 a very pale-yellow or almost wliite colour, was found to occur 

 on the larvae of a beetle — a species of Cryptorhynchus, which 

 tunnels into the stems of crotons, in St. Vincent. As many 

 as 50 per cent, of the insects are said to be attacked normally, 

 so that the fungus must contribute considerably to keeping 

 them in check. No fructifications of any kind were found 

 in connexion with the mycelium, though there is reasonable 

 ground for expecting that it belongs to a species of the genus 

 Cordyceps. 



TWO FrNi;i ON Li.ME TnKKs. Two bracket fungi found 

 on dead or dying lime trees in Dominica are recorded in that 

 portion of the 'A B C of Lime Cultivation', I'amphict iSeries 

 No. .53, devoted to the considei-ation of pests and diseases. 

 These are Pali/xlictus htj-sulns and Fumes Inridux. The former 

 is recorded as causing hairy sap rot of red gum timber 

 in the T7nited States (lUtlletin No. 114, Bureau of Plant 

 Industry, United States Department of Agriculture) and is 

 usually saprophytic. In identifying the specimens from 

 Dominica at Kew, Massee remarked, however, that this fundus 

 might very possibly be parasitic in habit, and recently it has 

 been found as a wound parasite on the mountain ash in the 

 United States, which it kills by slowly destroying the cam- 

 bium. It is possible, therefore, that this fungus may attack 

 lime trees in a similar manner. The second fungus, Pomes 

 luridn.t, found in Trinidad and Dominica, was not thought to 

 be a parasite when identified at Kew, but Fetch has since 

 shown that it is responsible for root disease of cocoa-nuts and 

 of flamboyant trees in Ceylon. 



