PEACH INSECTS 291 



nursery stock which has been properly fumigated with hydro- 

 cyanic acid gas. Where this is impossible the roots should be 

 cleaned of dirt and immersed for a few minutes in a strong 

 tobacco decoction to kill any lice which may have remained 

 upon them. When trees are found to be infested after they are 

 planted remove the earth about the tree to a depth of a few 

 inches and apply a pound or so of tobacco dust and replace the 

 earth. The tobacco acts both as an insecticide and as a ferti- 

 lizer, kilUng some of the lice and helping the tree to outgrow the 

 attack. The orchard should be kept under thorough cultiva- 

 tion and supplied with proper plant-food to promote a strong, 

 vigorous growth. If the aerial forms, on the new growth, be- 

 come troublesome at any time, they can be controlled easily by 

 thorough spraying with kerosene emulsion, whale-oil soap, 1 

 pound in 6 gallons of water, or tobacco extract combined with 



soap solution. 



References 



N. J. Agr. Exp. Sta. Bull. 72, pp. 20-23. 1890. 

 Cornell Agr. Exp. Sta. Bull. 49, pp. 325-331. 1892. 

 U. S. Dept. Agr. Yearbook, 1905, pp. 342-344. 1906. 

 N. J. Agr. Exp. Sta. Bull. 235, pp. 32-35. 1911. 



The Green Peach Aphis 



Myzus persicoB Sulzer 



The leaves, blossoms and young fruit of the peach are often 

 attacked by a pale green or greenish-yellow plant-louse which 

 sometimes causes serious injury to the crop. This European 

 insect was introduced into this country many years ago and is 

 now generally distributed throughout the United States and 

 Canada. It has a wide range of food-plants, including, besides 

 a number of deciduous fruits, the orange, many garden, truck 

 and ornamental plants and numerous weeds ; it is also a green- 

 house pest. Until recently the form infesting garden and green- 

 house plants has been known as Rhopalosiphum dianthi Shrank. 



