without the slightest danger of injury to the trees, and should be used 

 in sufficient quantity to thoroughly wet the soil to a depth of several 

 inches, as the aphides may penetrate nearly a foot below the surface. 

 To facilitate the wetting of the roots and the extermination of the 

 aphides, as much of the surface soil as possible should be first removed. 



Kerosene emulsion, at 20 to 30 per cent of kerosene, has given good 

 results in Georgia, as reported by R. I. Smith. ^ 



Mr. J. M. Stedman was the first to demonstrate the protective as well 

 as remedial value of finely ground tobacco dust. The desirability of 

 excluding the aphis altogether from nursery stock is at once apparent, 

 and this Mr. Stedman has shown to be possible by placing tobacco 

 dust freely in the trenches in which the seedlings or grafts are planted 

 and in the orchard excavations for young trees. Nursery stock may be 

 continuously protected by laying each spring a line of the dust in a 

 small furrow on either side of the row and as close as possible to the 

 tree, covering loosely with earth. For large trees, both for protection 

 and the destruction of existing aphides, from 2 to 5 pounds of the dust 

 should be distributed from the crown outward to a distance of 2 feet, 

 first removing the surface soil to a depth of from 4 to 6 inches. 



Since its early recommendation marked success has been reported 

 from the use of tobacco dust. A notable instance is that 'given by Mr. 

 M. B. Waite, of the Bureau of Plant Industry', who applied a ton of 

 tobacco w^aste, costing $25, in his orchard, with the result of entirely 

 renewing the vigor of his trees and producing a strong stubby grow^th of 

 twigs. A peck of tobacco dust was placed about each of his larger 

 trees in a circle of 2 or 3 feet around the trunk, and a slightly smaller 

 amount about trees from one to three years old. 



The tobacco kills the aphides by leaching through the soil, and acts 

 as a bar for a year or so to reinfestation. The dust is a waste product 

 of tobacco factories and costs about 1 cent per pound, and possesses 

 the additional value of being worth fully its cost as a fertilizer. 



The use of bisulphid of carbon for the w^oolly aphis is the same as 

 for the grape root-aphis. It should be applied in two or three holes 

 about the tree to a depth of 6 to 12 inches and not closer than li feet 

 to the crown. An ounce of the chemical should be introduced into each 

 hole, which should be immediately closed. The bisulphid evaporates 

 and penetrates throughout the soil and readily and promptly kills the 

 aphides. It does not, however, furnish any protection from future 

 attacks, and is attended with danger to the tree unless the precautions 

 named are carefully' observed. That it is highly' inflammable should also 

 be constantl}^ borne in mind. If it is to be used at all extensively, an 

 automatic injecting device should be secured. The chemical costs 

 about 10 cents per pound in 50-pound cans. 



iBul. 60, Bur. Ent., U. S. Dept. Agric, p. 79, 1906. 



