June 9, 1906 



HORTICULTURE 



731 



Dendrobium nobile 



The subject of the accompanying illustration is a 

 well flowered, fairly good type of Dendrobium nobile 

 one of the most popular and easiest managed of this 

 large and polymorphic genius. The species itself is 

 variable and includes many named and unnamed varie- 

 ties which are quite distinct. It is a native of the Him- 

 alayas and Eastern Asia and is imported in fairly large 

 quantities. Its distribution is large and it is so easily 

 grown and propagated that there is little danger of the 

 species ever becoming extinct. 



During the growing season the plants should have 

 plenty of heat and moisture, a temperature ranging 

 from 70 degrees to 90 degrees F. and a relative humid- 

 ity of about 80 per cent, will be just about right. A? 

 the growth is made in the summer months, these con- 

 ditions are easily maintained. In autumn and winter 

 somewhat drier and cooler treatment should be given, 

 but the common practice of carrying dendrobiums into 

 a cool house and keeping them dry as soon as growth 

 is finished is harmful and unnecessary. Sufficient sun- 

 light should be given to ripen the growths, but the 

 pseudo-bulbs should not lie allowed to shrivel. As Mr. 

 Cameron says in his notes on Thunias, Horticulture, 

 May 5th : '"Other conditions being right the question of 

 compost is not very important." Still the best for den- 

 drobiums is one that will allow plenty of root ceration 

 and dry out quickly enough to allow the application of 

 stimulants during the growing season. Peat and 

 sphagnum in proportions of 3 of peat to 1 of sphagnum 

 makes a healthy rooting-medium. It was considered 

 the right thing in England, not many years ago, to pot. 

 dendrobiums so firm that the newly-potted plant might. 

 be lifted by the pseudo-bulbs and swung around a per- 

 son's head without the plant coming out of the pot; 

 such potting is not to be recommended. The plant, 

 should be made so firm that it won't shake loose in 



handling, but without wedging. Baskets or perforated 

 pans are better than pots for dendrobiums as in such 

 receptacles there is less probability of the compost 

 becoming sour. 



Most dendrobiums can lie propagated by laying down 

 pieces of old pseudo-bulb on sphagnum moss and in a 

 favorable temperature the buds at the node will develop 

 into young plants. When air growths make their 

 appearance thej should he taken off with a portion of 

 the pseudo-bulb before the roots become very long as 

 roots which are developed in air will die when put into 

 compost. The flowers are borne on two-year-old growths 

 so that, if desired, the whole flowering growth may be 

 cut without injury to the young growth. 



Black Aphis 



• Columbus, Miss., May 29th, 1906. 

 Editor HORTICULTURE. 



Dear Sir: — I have some young apple trees, that are cov- 

 ered with little black lice, especially under the leaf. I 

 sprayed them twice with Sulphur Tobacco Soap, but it 

 did not do them much good. Now would you please let 

 me know, what would be the best thing to do for them to 

 remove the lice and keep them nice and clean. 



Hoping to hear from you immediately and by so doing 

 you will greatly oblige. 



Yours very truly, 



EDWARD E. BUDER. 



The lice, being sucking insects, require a contact 

 poison, to kill them by penetration and suffocation, the 

 standard solution for this purpose being kerosene emul- 

 sion. This is easily made by grating one-half pound of 

 whale oil or laundry soap into one gallon of boiling soft 

 water, or hard water softened by the addition of soda 

 or borax. When the soap is dissolved it is removed 

 from the fire and two gallons of kerosene is olowly 

 added while the mixture is hot. It is then churned for 

 ten or fifteen minutes until it has passed through a 

 milky stage and become creamy. The churning is very 

 important and to he effective the spray must reach the 

 creamy consistency. An easy way to do the churning 

 is to put the solution into the spray machine tank and 

 pump it back into itself for several minutes. 



This gives a stock solution which will keep for several 

 weeks. For use it is diluted just before being applied 

 at the rate of one part of the stock solution to nine 

 parts of water. 



Whale oil soap one pound to seven gallons of water is 

 another good contact insecticide. 



Bowker's Insect Emulsion used at the rate of one 

 gallon to tuenh gallons of water is also valuable where 

 a prepared spray is desired. 



It must he borne in mind that the lice are very rapid 

 breeders so if a lew escape they will quickly breed 

 enough to badly reinfest the trees in a few days. For 

 that reasorj frequent and thorough sprayings are neces- 

 sary, for to he effective the spray must touch the insect. 

 This is practically impossible to accomplish the first, 

 time because of (he small size of tin 1 lice and the rolling 

 of the leaf, due to their depredations, which partly pro- 

 tects them. However, persistent work will surely win 

 out. and mi' the trees are clean it will be an easy 

 matter t" keep them so. 



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