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THE AGRICULTURAL NEWS. 



December 23, 1905. 



INSECT NOTES. 



Tobacco Insects in Cuba. 



Bulletin No. 1 of the Estacion Central Agronomiea de 

 Cuba deals with the insect pests and fungoid and other 

 diseases of tobacco in that island. 



The insects dealt with in this bulletin are much the same 

 as those that have been found troublesome in the Lesser 

 Antilles, such as the tobacco worm, cutworms, flea beetle, 

 and the cigarette beetle which attacks stored tobacco. 



The tobacco worm in Barbados is Proti>parce celeu-i, 

 while the Cuban species is said to be Frotoparce Carolina. 

 The remedial measures in use in Cuba are the same as in 

 Barbados, which are hand-picking of the worms on the 

 leaves and, occasionally, the use of Paris green. 



Several species of cutworms are reported, for the control 

 of which a poison bait is recommended similar to that 

 recommended in the Agricultural Kcius, Vol. IV, p. .378. 



The Ilea beetle {Epitrix parvula) is the same species 

 that attacks tobacco leaves in Barbados. Paris green is 

 recommended for this pest also. 



The foregoing are the principal pests of growing tobacco 

 in Cuba. Clean cultivation is strongly recommended as 

 a general measure in all cases of insect attack. Paris green 

 is used in Cuba as a spray in a mixture of 1 lb. in 100 to 150 

 galkms of water, or dry, in a mixture of 1 lb. of Paris green 

 to 100 tt). of a dry powder, such as flour or slaked lime. 

 Although there does not seem to be any danger to the 

 consumer of the tobacco from the use of Paris green, it is 

 recommended that care be exercised not to apply more than 

 is necessary, and not to apply any for at least a month before 

 harvesting the leaves. 



In dealing with the cigarette beetle (Lasioderma serri- 

 corne) in stored tobacco, carbon bisulphide or hydrocyanic gas 

 fumigation is recommended, and these have been found not 

 to injure the equality of the tobacco. 



Black Blight in Grenada. 



In a report to the Agricultural Experiment Committee, 

 Grenada, Mr. R. D. Anstead, Agricultural Superintendent, 

 deals with the nature and contrc>l of the black blight which 

 is so prevalent in that island. 



The report reviews the relationship between the scale 

 insects attacking certain trees and the fungus growth 

 (CapiioJiiuu sp.) which finds suitable conditions for growth 

 in the excretions of these insects. 



The plants enumerated as most commonly infested by 

 the black lalight in Grenada are mango, bread-fruit, sapodilla, 

 guava, and rose-apple. The scale insects which are most 

 commonly followed by black blight are given as the star 

 scale {Vinsonia stellifern), the mussel scale {Mi/tilaspis citri- 

 roln). and the mealy shield scale {Frotopulvinaria piriformis). 



It is pointed out that scale insects rarely attack cacao 

 and nutmegs, although cases are known in Grenada of such 

 attacks, and that wild and uncultivated plants are frequently 

 attacked and furnish a source from which the infestation 

 may spread to cultivateil plants of certain kinds. 



The remedial measures recommended in Jlr. Anstead's 

 report are: (1) maintaining of cultivated plants in the 

 best possible condition of growth and vigour ; (2) clean 

 culture ; and (3) the application of insecticides. The 

 following formula is given for preparing a suitable insecti- 

 cide, which has been used for some time by the Entomologist 

 on the staff of the Imperial Department of Agriculture : — 



Six (6) ounces of the best rosin are finely powdered and 

 added to 3 pints of crude oil (Barbados tar) and heated until 

 all is dissolved. Four (I) ounces of napthalin are then added 

 and 6 lb. of whale oil soap, and the heating continued until 

 the mixture is homogeneous. One (1) pound of this mixture 

 is made up with 10 gallons of water and used as a spray. 

 The rosin must be of the best quality, or trouble is exjieri- 

 enced in the clogging of the nozzle of the sprayer. 



This mixture may be used for spraying, or plants may 

 be washed with it. When no spraying outfit is available, 

 a small brush may be used to apply the mixture and to 

 dislodge the scales. 



The report also recommends concerted action on the 

 part of all members of the agricultural community in 

 dealing ^ith this matter, and suggests that some fornr of 

 legislation may be necessary to deal with cases where 

 owners are negligent and allow their plants to become 

 breeding places for scale insects and a source of infection 

 to their neighbours. 



In dealing with large trees badly infested with scale 

 insects and black blight, it is recommended that such trees 

 be lopjied as close as possible, the cuts tarred over, and the 

 whole thoroughly coated with a good lime wash. 



BASIC SLAG. 



The following extract from an article on basic 

 slag, in the Jimrnal of the Board of Aijrivnlture 

 (Great Britain), for November, is likely to be of interest 

 to West Indian planters: — 



Basic slag is a by-product in the manufacture of steel 

 and its composition is not regulated by the manufacturer 

 as is the case with, say, superiihosphate. Iron ores contain 

 irregular quantities of phosphorus (the substance which 

 gives to the phosphate of lime found in bones and some other 

 manures its value as a fertilizer), and the object of the steel- 

 maker is to get rid of all the phosphorus in the iron. To 

 effect this the iron is melted in contact with limestone, which 

 extracts the phosphorus and forms a slag. Thi.s, when, 

 ground to a fine powder, is basic slag, which may vary very 

 considerably in quality, the usual contents being 30 to 40 

 per cent, of insoluble phosphate, though there may be as 

 little as 22 per cent., or as much as -15 per cent. 



The Irish Department, in their leaflet dealing with basic 

 .slag, point out that there is nothing in the aiii)earance of 

 basic slag which gives the slightest indication of the percent- 

 age of phosphate of lime it contains, and recommend that 

 the farmer should (1) stipulate when purchasing that he 

 shall be sui'plied with a high-class slag ; (2) insist on being 

 furnished with an invoice on which are clearly stated (a) the 

 percentage of phosphate of lime, (b) the fineness of grinding, 

 and (c) the percentage of phosphate of lime soluble in 

 a 2-per cent, solution of citric acid according to Wagner's 

 method. There should be no difMculty in procuring from 

 any reliable manure merchant basic slag which contains 40 

 per cent, of pho.sphate of lime and so finely ground that at 

 least SO jier cent, of it will pass through a sieve having 

 10,000 holes per scjuare inch, and in which at least 80 per 

 cent, of the total [ihosphate ot lime is soluble in a 2per cent, 

 solution of citric acid used according to Wagner's directions. 



