MARCH :U. IS'JS. 



The Weekly Florists' Review. 



737 



An Easter Thought. 



LArranged and Photographed by Mr. \V. T. Bell, Franklin, Pa.] 



—hence a tobacco soap is better than a 

 tobacco tea, though neither is equal to a 

 tobacco smoke. 



There is another point worthy of at- 

 tention in the greenhouse. If soaps are 

 to be used, those made with potash 

 rather than with soda should be se- 

 lected. Potash is a plant food and 

 when washed into the soil acts as a fer- 

 tilizer and is taken up and removed by 

 the vegetable growth. Soda on the con- 

 trary in the form used in soaps is actu- 

 ally deleterious to the plants when pres- 

 ent in any quantity, and a frequent use 

 of suds made with a soda soap may eas- 

 ily impair the value of the soil for plant 

 growth. In general, hard soaps are 

 soda soaps, while soft soaps are potash 

 soaps. 



Dry powders are rarely used in the 

 greenhouse, but whenever they are to be 

 employed the reasons that call for a fine 

 spray, call for the finest possible dust. 

 The finer the dust, the more effective the 

 application. Coarse particles are readily 

 sifted out, but fine fragments penetrate 

 and get into the body cavity where they 

 can produce their characteristic effect. 



Of the oils, kerosene only has been 

 used to any extent, and this is a most 

 valuable insecticide where its use is al- 

 lowable. It is very effective even when 

 greatly diluted, but it must be first 



emulsified before it can be mixed with 

 water. This emulsion is prepared as fol- 

 lows: 



Hard soap shaved fine, Vz pound. 



Water, 1 gallon. 



Kerosene, 2 gallons. 



Dissolve the soap in boiling water and 

 pour the kerosene, which should also be 

 slightly warm, into the boiling hot suds 

 — churn rapidly with a force pump for a 

 few minutes, and you will get a beauti- 

 ful, snow-white butter which will keep 

 in a cool place for weeks, and will dis- 

 solve readily in water to any extent. 



Thus much for insecticides in general, 

 and now a few words concerning a very 

 few kinds of insects. Of course the same 

 conditions that favor the growth of 

 plants also favor the development of cer- 

 tain kinds of insects, and particularly, 

 plant lice or aphides, commonly called 

 "green-fly" or "black fly" according as 

 they vary in color. 



These are peculiar in several respects 

 and particularly their mode of multipli- 

 cation. Their appearance I will not un- 

 dertake to describe, but if a single large 

 individual be observed for a few days in 

 succession, it will be noted that a colony 

 of small specimens, daily increasing in 

 size and number, forms round here, and, 

 as these attain full size in a few days 

 they move off a little distance and in 



turn become centers of new colonies. If 

 the watch be continuous and close, it may 

 be observed that every few hours the 

 mother of the colony gives birth to a liv- 

 ing young and all her descendants are 

 apt to be like herself, viviparous, par- 

 thenogenetic females. Some of them be- 

 come winged, but that is not necessary 

 to enable them to begin reproduction. 

 Under greenhouse conditions no males 

 art produced as a rule, and multiplica- 

 tion goes on with great rapidity. It is 

 against such insects that the florist is 

 most frequently called to battle, and be- 

 sides the methods already mentioned, it 

 may be in place to say that single plants 

 may be often completely cleaned bv the 

 use of bisulphide of carbon. Bisulphide 

 of carbon is a clear liquid like water 

 which volatilizes rapidly, giving off an 

 extremely foul odor which is poisonous 

 to insects when confined in it. A dram 

 is sufficient to poison one cubic foot of 

 closed space, so as to kill plant lice with- 

 out harming plants in one hour. In a 

 closet constructed for the purpose, a 

 number of plants might be placed at one 

 time and completely cleaned, whenever 

 such cleaning was desirable, as before 

 sending to a customer. As the vapor is 

 heavier than air and sinks, the bisul- 

 phide should be evaporated in a shallow 

 dish secured in some way near the top of 

 the closet. The objection to this mate- 

 rial is its inflammability, but so long as 

 this peculiarity is kept in mind it can be 

 used with entire safety. 



A somewhat similar process has of late 

 been the subject of experiment in clean- 

 ing entire houses of insects by the use of 

 hydrocyanic acid gas. This is secured 

 by the action of dilute sulphuric acid on 

 cyanide of potassium, and it is exceed- 

 ingly poisonous to animal life of all 

 kinds. The proportions are: 



Fused cyanide of potassium, 

 9S per cent pure, 1 oz. weight. 



Sulphuric acid, 1 oz. measure. 



Water, 3oz. measure. 



Use a glazed earthenware vessel and 

 put in first the necessary water, then add 

 the acid, and when all is prepared drop 

 in the cyanide in small lumps. The for- 

 mation of gas begins at once and the 

 amounts above given will thoroughly 

 fill lOO cubic feet of space. Plant lice 

 succumb in a few minutes, scales in from 

 one half to one hour— plants very soon 

 thereafter. I do not know enough of the 

 practical use of this gas to say much of 

 its possibilities. I know that it has been 

 used in some large houses: but I do not 

 know the details. It is an exceedingly 

 dangerous thing in careless hands, yet it 

 may develop into a valuable method 

 when we become better acquainted with 

 its range and its possibilities. 



Among the most troublesome green- 

 house pests are scales: soft and armored. 

 Soft scales are usually of considerable 

 size; of the texture their name implies 

 and brown in color. The young are 

 smaller, much flatter and paler: usually 

 quiescent, but capable of motion. In 

 some species the young are produced 

 alive, in some eggs are deposited under 

 the female scales. Whichever is the case 

 the florist must study the species until he 

 knows when the young larvae are being 

 produced. Then he should apply his 

 washes promptly and thoroughly and at 

 sliort intervals, for the larvae scales are 

 easily killed, and once out of the way the 

 plants will remain clean. Soap washes 

 are best in this case, although, tobacco 

 will do, if frequently used. The main 

 point to be observed is the time when 

 the young appear and prompt applica- 

 tion as soon thereafter as possible. 



The armored scales differ from the soft 

 scales or Lecaniums in that the scale Is 

 separate from the insect itself which lies 

 free beneath it. The armored scales 

 have no power of motion when they are 

 once fixed to the plant and their chance 

 to travel is confined to a day or two 

 just after they are born or hatched as 

 the case may be. Treatment is much as 

 already advised and is also effective in 

 proportion to the promptness and thor- 

 oughness with which the application is 

 made. No use to apply weak washes to 

 mature scales. 



