16 Farmers’ Bulletin 1128. 
THE RUSTY PLUM APHIS.! 
The rusty plum aphis was discovered and named from individuals 
feeding on grass, but is better known by its injuries to plums. It is 
rusty brown or deep purplish, with white bands upon the legs. 
This species feeds upon the tender twigs and foliage of the plum 
and also upon the peach. The first slamanellian attack the buds 
just as they are expanding in the 
spring and later crawl down among 
the opening leaves. As the season 
advances whole twigs or small 
branches may be literally crowded 
with the aphids (fig. 9), and such 
twigs usually die. Another species, 
not yet named, also has this habit, 
and this form may be very injuri- 
the plum throughout the summer. 
SEASONAL HISTORY. 
The eggs of the rusty plum aphis 
hatch ake in the spring and the 
normal life period of the stem- 
mother is about a month. Dur- 
ing this time she produces young 
at the rate of four to six a day. 
In a little over a week these 
young are mature and reproduc- 
ing, so that large colonies soon 
result. A few winged forms occur 
in the early generations, but it is 
not until late spring that a large 
percentage of spring migrants is 
found. These winged forms fly 
from the plum and settle upon vari- 
ous grasses, where they produce 
colonies throughout the summer 
around the crowns of the plants. 
In October the fall migrants are 
_.| produced upon the grasses, return 
Fig, 9.—The rusty plum aphis: Colony onshoot to the plum, and there give birth 
ge cine esa to the egg-laying wingless females. 
The males also produced upon the grasses, migrate to the plum 
in order to locate and fertilize the nares Females! In some 
regions the species seemingly lives on the plum throughout the 
year. 
Hesteroneura setariae (Thos.). 
ous to the twigs, as it remains on > 
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