PLUM INSECTS 259 



a small amount of soap has been added. Fortunately this 

 species does not curl the leaves to any great extent, thus making 

 it easier to do effective work. 



References 



N. Y. (Geneva) Agr. Exp. Sta. Bull. 139. 1897, 

 Col. Agr. Exp. Sta. Bull. 133, p. 39. 1908. 



The Rusty Brown Plum Aphis 



Aphis setarioB Thomas 



This dark rusty brown plant-louse occurs throughout the 

 Southern states and is found as far north as Minnesota. It 

 sometimes causes considerable loss 

 to the plum crop, particularly in the 

 South, and has been known to at- 

 tack the peach, being especially 

 troublesome on newly budded peach 

 stock in nurseries. It is sometimes 

 called the southern plum aphis under 

 the scientific name of Aphis scotti. 

 The general color of the body is 

 rusty brown with the base of an- 

 tennse, tibiae and tail white. 



The dark brown shining winter ^^ 226. - Stem-mother of 

 eggs are attached to the smaller the rusty brown plum aphis, 

 branches and hatch about the time f^tT'' ^^''' ^^''^'''"' ^"^ 

 the buds open. The first brood 



consists entirely of wingless females known as stem-mothers 

 (Fig. 226) ; they give birth to living young which develop into 

 wingless females. There are ten or more generations during 

 the season. The earlier broods are wingless, but as the 

 leaves become crowded winged individuals are produced 

 which migrate to other plants, mostly grasses, and start new 



