F,L?>T LEAF CT;RI, and WOOLLY APPLE APHID. 249 



The much more important root feeders, however, are more 

 •diffiicult to reach and exterminate. The common recommenda- 

 tions are of appHcatlons of strong soap or tobacco washes to the 

 soil about the crown, or soot, ashes, or tobacco dust buried about 

 the roots ; also similarly employed are lime and gas-lime. 



Badly infested nursery stock should be destroyed, since it 

 would be worth little even with the aphides removed. 



Proper cultural methods can hardly be overestimated in their 

 value as a protection of young trees, as neglected orchards not 

 'only suffer heavily but serve as a breeding ground, dangerous to 

 the neighboring trees. 



Formula A — Tobacco Decoction. 



Tobacco stems or tobacco- dust 2 pounds 



Water 4 gallons 



'Put the tobacco in the water, enough to cover, which may be either 

 cold or hot. Place over the fire and when the water has reached the 

 Tjoiling point, remove some of the fire and allow the water to simply 

 simmer for fully one hour, when the liquid is ready to be drained off, 

 diluted to the above proportions and applied. Boiling violently drives 

 off the nicotine. 



If whole-leaf tobacco is used, prepare as above, using one pound of 

 tobacco to each four gallons of water. 



No lime or other alkaline substance should' be added to the tobacco 

 -while cooking. Apply at once, or within a few days after making if 

 possible. 



Certain reliable extracts such as "Black Leaf," "Black Leaf 40," and 

 "Nikotecn" are on the market and can be secured through local drug- 

 gists. (The Black Leaf preparations are manufactured by The Ken- 

 tucky Tobacco Product Company, Louisville, Ky., and are carried by 

 the Collins Hardware Company, 97 Friend St., Boston, Mass. Nikoteen 

 is manufactured by The Nicotine Manufacturing Company, St. Louis, 

 Mo., and can be secured from Joseph Brick & Sons, 47-54 N. Market 

 St., Boston, Mass.). 



Directions for use come with the products. There is nothing to do 

 in the preparation of these extracts except to stir the contents of the 

 can before pouring out any quantity for dilution. In most cases one 

 gallon of the Black Leaf will be found sufficient for each seventy gal- 

 lons of water. But if in the treatment of any louse this does not seem 

 sufficient it may be used in preparation of one gallon to sixty or sixty- 

 five gallons of water. Careful sprayers have usually succeeded in 

 killing plant lice with this preparation in the proportion of one gallon 

 to each one hundred gallons of water. Thoroughness of application 

 is of as much importance as the strength of the 'material used. 



