104 



to those on the roots at almost any time of the summer 



and fall. 



This insect is universally distributed and extremely 

 common, both in orchards and nurseries, becoming evi- 

 dently more so to the southward. Being highly injur- 

 ious to young trees, it is a difficult pest to deiil w\^h in 

 the nursery trade. It probably cannot be wholly erad- 

 icated from an infested nursery, and, perhaps, can never 

 be completely and permanently kept out of a new plan- 

 tation. Fortunately, trees a few years old, once well 

 established, commonly suffer but little from its pres- 

 ence, and our jireventive and remedial measures must 

 consequently be directed to the preservation of young 

 stock. No tree whose roots are visibly injured by the 

 woolly aphis should be allowed to go from the nursery, 

 and none in the least infested by it should be sent out 

 until the roots have been freed from it by insecticide ap- 

 plication. 



The simplest method of destruction of the aphis on the 

 roots is dipping for a few seconds in water kept heated 

 to 130-150 deg. Fahr. Where heat cannot be conveniently 

 maintained, kerosene emulsion, diluted to contain about 

 ten per cent, of kerosene, may be substituted. In the 

 nursery, seedlings or graftings may be protected by using 

 tobacco dust freely in the trenches in which they are 

 planted, or by sprinkling together dust in a shallow fur- 

 row along each side of the nursery row as closely to the 

 tree, and afterwards covering loosely with earth. In- 

 fested trees should not be sent out from the nursery 

 except after fumigation with hydrocyanic acid gas or 

 after dipping the roots in hot water or in kerosene emul- 

 sion. Trees with aphis galls or knots should never be 

 sold, but thrown out and burned. Trees which have 

 been growing longest in the nursery are usually the worst 

 infested. Culls kept from year to year, apt to be mere 

 nurseries for the multiplication of these and other de- 

 structive pests. In preserving overgrown trees in hope 

 of making a cheap sale, the nurseryman usually ''saves 

 the penny and loses the pound." 



