

tfORTICU LTURE 



D (ember 9, 1911 



DESTROYING INSECTS UNDER GLASS 



BY W. F. MASSEY. 



Those of u.s who have worked under 

 glass a good part of our lives know 

 the bother and worry of tobacco fu- 

 migation tor the aphides and the stale 

 odor oi everything In the house re- 

 sulting therefrom. Then, after all, it 

 is hut a temporary check and we have 

 to go through the same thing another 

 1 suppose that we will always 

 eontinue to use tobacco in some form 

 tor the aphides, but there are so many 

 other pests in the greenhouses thai 

 are not affected by the tobacco smoke 

 that it is important to have something 

 to destroy these as well as the aphides. 



By careful syringing we can keep 

 reasonably free from red spider on 

 many things, but there are crops un- 

 der class, like tomatoes, which do not 

 like overhead spraying, and if the un- 

 derfoot moisture is not well main- 

 tained, these may get infested with the 

 mites. 



Then it is well known to florists that 

 there are many ferns that object to 

 water on their fronds and which also 

 are damaged by tobacco smoke, and 

 it has been a matter of discussion 

 whether, in fumigating with tobacco, 

 we should syringe first or after fumi- 

 gating. I have heard gardeners insist 

 that plants would be damaged if not 

 syringed before fumigating. The fact 

 is that it makes little difference wheth- 

 er they are wet or dry, for some plants 

 will not be damaged by smoke under 

 either conditions, while other plants 

 will suffer somewhat, whether sprayed 

 or not. 



Then there are insects that infest the 

 frames and tobacco fumigation is a 

 different matter in a frame, and while 

 tobacco fumes are a specific against 

 aphides, the red spider does not mind 

 them and the white fly is unharmed, 

 and the sow bugs that infest the or- 

 chids are not hurt. What is needed is 

 a deadly fumigation that penetrates 

 every place and is destructive to every 

 form of animal life in the house while 

 not injurious to the plants. No fumigat- 

 ing material has been discovered which 

 meets these requirements as well as 

 l he cyanogen or hydro-cyanic acid gas, 

 formed by the combination of sul- 

 phuric acid with cyanide of potassium. 

 When sulphuric acid is added to cy- 

 anide of potassium, or rather when 

 the cyanide is placed in the sul- 

 phuric acid, there is a complete decom- 

 position and the cyanogen is set free, 

 while the sulphuric acid unites with 

 the potash and falls in a powder, form- 

 ing the sulphate of potash which every 

 cultivator knows is valuable as a fer- 

 tilizer in the soil. 



Seme have claimed advantages for 

 sodium cyanide for use with sulphuric 

 acid for fumigating purposes. But I 

 can see no advantage in its use, but 

 many disadvantages. The cyanogen 

 at. d from a given quantity of po- 

 tassium cyanide can be produced at a 

 lower cost than a similar amount from 

 sodium cyanide. 



It is true that it is claimed that it 



takes 132 kilograms of potassium cyan- 

 ide to generate the same volume of 

 gas as is contained in 100 kilograms 

 of sodium cyanide. I say "contained" 

 in it. because the difficulty comes in 

 making a complete decomposition in 

 the acid. Sodium sulphate rapidly 

 forms on the mass and hardens and en- 

 closes a portion of the sodium cyanide 

 so that the sulphuric acid will not act 

 upon it. 



When potassium cyanide is added to 

 sulphuric acid, the sulphate of potas- 

 sium that is formed tails in a powder 

 and the decomposition of the cyanide 

 is complete, the cyanogen escapes into 

 the air to accomplish its deadly work, 

 and till that is left is of value to the 

 cultivator, while if the sodium cyan- 

 ide is used, the resulting sodium sul- 

 phate is absolutely useless to vegeta- 

 tion. In the one case the operator 

 saves a valuable by-product and in the 

 other he gets less gas and a by-product 

 worthless for farm or garden pur- 

 poses. 



To the vegetable grower under glass 

 it seems to me that this cyanogen fu- 

 migation is especially valuable. It is 

 hard to rid a crop of lettuce even of 

 aphides with tobacco smoke without 

 spoiling the quality of the lettuce, 

 and when once the green caterpillars 

 infest the lettuce, there is no way in 

 which they can be at once effectually 

 destroyed better than by a good fumi- 

 gation. The fumigation of a frame is 

 even easier than that of a greenhouse, 

 since the operator is already outside 

 and only has to raise a sash, drop the 

 cyanide and close the sash, while any 

 one who has tried to fill a cold frame 

 with tobacco smoke knows how hard 

 it is to do it. 



Some plants with rough or hairy 

 leaves are sometimes injured by the 

 fumigation. I have seen a statement 

 in a bulletin from one of the Experi- 

 ment Stations that this gas will not 

 destroy mature insects, nor scale. If 

 this was true, there would be little use 

 in the fumigation of dormant nursery- 

 stock. The fact is that dormant trees 

 and leafless plants can stand a longer 

 fumigation than plants in a growing 

 state. Fumigation in tight quarters 

 is certainly the most penetrating reme- 

 dy and misses less than spraying. 



For fumigation of nursery stock the 

 house where the work is done should 

 be made as nearly gas-tight as possi- 

 ble. For each 100 cubic feet of space 

 there will be needed one ounce of po- 

 tassium cyanide,, one and a quarter 

 fluid ounces of sulphuric acid and three 

 ounces of water. Place the water and 

 sulphuric acid in a deep stone crock, 

 or wide-mouth open jar. Break the 

 potassium cyanide into pieces the size 

 of a marble and pour them into the 

 crock and shut the door as quickly as 

 possible. If the fumes are left on the 

 trees an hour, every insect and even 

 the San Jose scale will be destroyed. 



The fumigation of hot houses needs 

 more care. For each 100 cubic feet of 

 space in the house use half an ounce of 

 potassium cyanide, six-tenths of an 

 ounce of sulphuric acid and one and a 

 half fluid ounces of water. Select a 

 moderately mild night and use the acid 

 and cyanide soon after sundown and 



the house and air it out by nine 

 or ten i 'cli 



The following is recommended for 

 the white By and lettuce aphis: For 

 each 1000 feet cubic space use one- 

 fourth ounce of the potassium cyanide, 

 three-tenths of an ounce of sulphuric 

 acid and three-quarters of an ounce of 

 water. Make the gas soon after sunset 

 and leave the house closed all night. 

 In airing out the house after fumiga- 

 tion, open all doors from the outside 

 and let the air pass through for some 

 time, before entering to open the ven- 

 tilators. 



In large greenhouses it is best to 

 have a row of jars with operators to 

 run each way and drop cyanide as they 

 pass the jars toward the doors, plac- 

 ing a jar for each 1000 cubic feet of 

 space in the house. Where houses are 

 built on the ridge and furrow plan and 

 open to each other, about the only 

 way will be to have a jar in each sec- 

 tion, about midway, and a man to drop 

 the cyanide and hasten to the door in 

 each house. 



By having the cyanide in little 

 cheesecloth bags attached to a cord 

 running through a staple overhead, a 

 man can stand some distance away and 

 drop the cyanide and get out and close 

 the door in a long house. 



PINES. 



About 48 per cent, of the total lum- 

 ber output of the United States in 1908 

 was pine, showing how important to 

 the lumber industry of the country the 

 37 species of pine grown in the United 

 States area. 



No one species grows in all the 

 states, yet, with perhaps one exception, 

 no State is without one or more. Some 

 occupy large regions in considerable 

 abundance, while others are so scarce 

 that few persons ever see and recog- 

 nize them. Yet no species of pine is 

 so scarce that it is not made in some 

 way to serve man's need. 



Four important timber trees of the 

 southeastern United States are usually 

 grouped as one in the lumber markets 

 and are sold under the common name 

 of yellow pine. They are the long- 

 leaf pine, short-leaf pine, loblolly pine, 

 and Cuban pine. While in appearance 

 the woods of these four trees are so 

 nearly alike that it is sometimes dif- 

 ficult to distinguish one from the other, 

 still in some particulars, there is con- 

 siderable difference. 



Although the long leaf pine, white 

 pine, western yellow pine, western 

 white pine, and the loblolly produce 

 most of the pine lumber manufactured 

 in the United States, the U. S. Depart- 

 ment of Agriculture in Forest Service 

 Bulletin No. 99, considers each species 

 separately, giving in detail, its physi- 

 cal properties, the supply, its early 

 uses, manufacture and products; and 

 in the case of the more important spe- 

 cies, specifies the more important uses 

 to which it is put. The places which 

 some species occupy are very humble, 

 and they can never rise much in the 

 scale of usefulness, yet each one is en- 

 tith d to its own individuality. 



