10 



FUMIGATION WITH TOBACCO PREPARATIONS. 



Tobacco extracts and fumigating powders iiave been extensively 

 used for a number of years by ilorists as fumigants against aphides 

 and other insects occurring in greenhouses, such as white %, thrips, 

 and other small, delicate, and soft-bodied insects. The extracts con- 

 tain a larger proportion of nicotine than ordinary decoctions prepared 

 by steaming waste stems and powdered tobacco, and are therefore 

 much more effective, which is true also of the powdered fornis of nico- 

 tine. A number of these preparations are on the market and are 

 advertised in the principal florists' journals and in other agricultural 

 periodicals. They are used in various ways, and directions are fur- 

 nished with the packages purchased. The liquid preparations vary in 

 strength from 35 or -iO per cent up to 80 to 85 per cent nicotine. 



FIELD FUMIGATION WITH TOBACCO. 



During the years 1904 to 1906 the employment of tobacco or nico- 

 tine preparations in destroying the melon aphis in the field was the 

 subject of experiment in Texas b\^ Messrs C. E. Sanborn and E. D. 

 Sanderson." These have stated to the writer that, judging from their 

 experimental use of this method and its practical use b}^ extensive 

 growers, it bids fair to become the best method of dealing with the 

 melon aphis in its occurrence in the South. The process is in brief 

 the fumigation of a dry preparation under a cloth-covered frame 

 placed over the affected vines. In 1905 and 1906 the writer found 

 that a very short exposure to tobacco fumes killed aphides, when other 

 insects, such as thrips, survived a considerably^ longer treatment. 



In practising this method Mr. Sanborn has used apparatus substan- 

 tiall}' as follows: 



Preparation of the frame and cover. — For vines 2 or 3 feet long he 

 advises a light frame tt by 6 feet, supported by legs 8 inches in length. 

 Lumber three-fourths inch thick and 2 inches wide is suitable. 

 Strengthen the frames by connecting the ends with acrosspiece. Two 

 diagonals are also used for strengthening the frame and for conven- 

 ience in handling, the latter being attached after the cloth cover is in 

 position. The cover is of muslin of a cheap grade (7 or 8 cents a 

 yard) and sufficiently compact to prevent a passage of gas thru its 

 meshes after being oiled. Its size should be about 2 feet wider and 

 2 feet longer than the frame which it covers. This is sufficient for an 

 8-inch wall and a 4-inch lap to the ground. Dirt is placed about the 

 bottom to keep the gas from escaping there. 



After the cloth has been cut and sewed into the sizes desired it is 

 saturated in a vessel of linseed oil which fills the pores. It is then 



« An experiment with tobacco smoke as a remedy for this species was made by 

 Dr. S. A. Forbes in 1882. The result was not a perfect success, for the reason that a 

 bee smoker was used and the smoke was blown under canvas hay caps covering the 

 affected plants. Nevertheless from 50 to 75 per cent of the aphides were killed by 

 10 minutes' exposure. 



