62 



THE AGRICULTURAL NEWS, 



Ffbruaey 1-2, 1916. 



PLANT DISEASES, 



OF ORANGES. 



information was received by the 



SPOTTING 



Some two years ago 

 Imperial Department of Agriculture of the prevalence on an 

 orange estate in Dominica of a form of fruit spot which was 

 believed by the grower to have some connexion with 

 subsequent rotting of the fruit in transit. 



Specimens of the afTected fruit w^ere examined by the 

 writer, and a report made, of which the following is a portion: 



'The spots in question are roundish, and mostly about 

 1 cm. in diameter. They are slightly depressed, and more or 

 less browned. Close examination shows that the superficial 

 tissue occupying the spaces between the oil glands has sunken 

 somewhat and turned brown, while the latter being unaffected 

 stand out from the surface of the spot as small green and 

 yellowish papillae. 



'Sections of the rind showed that the cuticle was usually 

 intact. In the fresher-looking examples scattered cells of the 

 epidermis had turned brown, and some amount of the sub- 

 epidermal tissue was brown and shrunken. It is the shrinking 

 of the tissue which is the immediate cause of the spots. In 

 examples in which the injury was either older or more severe, 

 cork formation more or less complete according to the apparent 

 age of the lesion was cutting off, or had cut off, the injured 

 tissues. 



'No fungus or bacterium was found in association with 

 the spots. Fungi of the types composing the u.sual "black 

 blight" were present to a small e.'ctent and mostly in incipient 

 stages all over the rind, but were not more especially develop- 

 ed on the brown spots in any constant degree. In the cases 

 where there was an increase it was not more than would be 

 accounted for by the effect of the depressions in arresting 

 spores and retaining a little moisture. 



'Oranges bearing the spots have been kept under obser- 

 vation for seven days, some exposed in the laboratory and 

 others in moist chambers. In neither case has any alteration 

 in the apjiearance of the spots taken place. On the whole, the 

 oranges have kept reasonably well. A few of tho.se which were 

 exposed rotted early, the rest are still sound. Most of those 

 in the damp chambers are now beginning to rot. Again in 

 neither case is there any reason to associate the rotting with 

 the spots in question. One orange with two spots kept in 

 a moist chamber in association with rotten oranges covered 

 with spores eventually developed mould at the stem scar 

 while the spots were still unaffected. 



'Experiments in producing spots artificially showed 

 that a similar appearance could be brought about by pricking 

 the rind ; this caused the sub-epidermal tissue to dry up. 



'The actual cause of the spots could only bo ascertained 

 by study of the oranges on the iree.-. Repeated thorn pricks, 

 sun scald, or the feeding of a large sucking insect may be 

 suggested as possible origins.' 



A note by Mr. H. S. Fawcett in the Californian Monthly 

 BuUelin for September 191-5, p. 431, describes spots with the 

 same characteiistics as occurring on lemons and oranges in the 

 California packing houses, where tliey are known as 'green 

 spots'. They may later turn reddish or browTiish. The grade 

 of the fruit is lowered owing to the effect on its appearance, 

 but the keeping quality is usually not seriously injured. 



The interest of the note lies in its suggestion of the 

 cause of the blemi-shes. It has been found that a very small 

 amount of the essential oil of the rind, if it escapes on to 

 the surface of a green fruit, is capable of producing, even on 

 an uninjured area, the typical spotting. 



It has been noticed that green fruits picked while wet 

 were more liable to develop spots than those picked the same 



day when dry, and the same difference was found between 

 fruits kept in jars with moist air and those kept in dry air. 



The same type of spot is noticeable to various extents on 

 oranges from neighbouring islands marketed in Barbados. It 

 would appear that the conditions in Dominica, owing to the 

 humidity of the atmosphere, are especially favourable to the 

 development of the spots. 



Great stress has been laid by all competent authorities 

 on the need for care in picking and handling citrus fruit 

 intended for sale, and this discovery emphasizes such advice 

 by showing that the most minute injury may lead to a very 

 noticeable blemish. 



W.N. 



WEST INDIAN PRODUCTS. 



DRUGS AND SPICES ON THE LONDON 



MARKET. 



Mr. J. R. Jackson, A.L.S., has forwarded the follow- 

 ing report on the London drug and spice markets 

 for the month of Deceniber: — 



The last month of the year started with a fair amount of 

 business being transacted in both drugs and spices. Large 

 quantities of most of the articles were brought forward from 

 week to week during the period under review, the first 

 auction being held on December 2, and the last on the 30th, 

 The usual slackness on the approach of the Christmas and 

 stock-taking seasons was apparent, but not so acutely marked 

 as in ordinary years. Prices generally have been very tirm for 

 all the products that come under our notice, and with the 

 increased rates of freightage there seems to be no prospects- 

 of a reduction. 



GINGER. 



At the beginning of the month there were no offerings 

 of Jamaica, but Sierra Leone was quoted at 29.s-. per cwt. At 

 auction on the i-'nd, it was reported that the stocks of. 

 .Jamaica were small, COs. to 67s. 6rf. per cwt. being (juoted. 

 for ordinary to medium, and 67s. to 7.5s. for good to fine. 



NUTMEGS .\ND M.\CE. 



At auction on the 8th of the month, ;59(; packages of 

 West Indian nutmegs were offered and sold, ()9's to 76's 

 fetching lOrf. to Is., and smalls i\d. to 5 jrf., being an advance 

 of \d. to Hid. on previous rates. At the same auction 232 

 packages of West Indian mace sold at Is. \d. to Is. lOd.,. 

 being \d. advance on previous rates. 



SARSAP.^Rn.L.\. 



At the first ilrug auction on the 7lh of the month, .sarsa- 

 parilla was in good supply as follows: Grey .Jamaica 22 bales, 

 native .Jamaica 57 bales, Lima 35, Mexican 22, and 

 Honduras 7 bales. Of the grey .Jamaica, 11 bales found buyers 

 at l.s. 8d per 11). for fair, and Is. 7c?. for part coarse and 

 slightly mouldy. Only 7 bales of the native Jamaicii 

 were disposed of, 8(/. to %d. being paid for inferior yellow 

 dull red, part of which was sea-water damaged. The Lima- 

 .Jamaica, which was nn.re or less damp and mouldy, was 

 bought in at Is. 8rf. per B). No buyers were found either 

 for the Mexican or Honduras. 



CITKIO ACID, UME OIL. LIME JUICE, KOLA, CASHEW NUTS, 

 TAMARINDS, PIMENTO, AND ARROWROOT. 



Citric acid commenced with a very dull market at 

 2s. 9rf. to 2s. lOrf., and a^ the end of the month it dropped 

 to 2s. M. with very little demand. There was also very 



