42 NEW YORK STATE MUSEUM 
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making possible the production of many generations during a 
season. Messrs Houser, Guiton and Lowry’ have estimated that 
the total progeny and offsor‘ng of on fo~ a per‘od of two weeks may 
amount to 76 aphids. They found on one small potato plant having 
only seven leaves 1237 aphids and on a large spreading plant with 
twelve stalks 34,688 plant lice and another large one had 25,750 
aphids. The rate of reproduction is such that it would require 
only two weeks for 456 producing females to colonize the most 
seriously infested of these plants. With these figures in mind it 
is not surprising that an aphid outbreak:-may develop rapidly and 
become extremely destructive almost before the presence of the 
pests is suspected. 
This aphid breeds freely upon potato, tomato, egg plant, pepper 
and sunfower and may be ‘found commonly, though not in large 
numbers, upon such well-known plants as jimson weeds, ragweed, 
lamb’s quarters. sweet potato, canna, hollyhock and matrimony 
vine. It also occurs, though less commonly, upon a number of 
other plants so that it is comparatively easy for this aphid to 
ma nta'n itself in any local'ty where climatic conditions are suitable. 
Characteristics of ovthreak. The plant l’ce attack the tender 
young leaves. causing the edges to turn downward and after a 
short t’me the fol’age shrivels and we have a characteristic dying 
condition. h’s progresses from the top downward and in very 
seriously infested fields all the foliage may speedily succumb, part 
of th’s being very likely due to plant diseases as well as to insect 
injury. 
The tomato ‘s also very lable to infestation, the aphids first 
work'ng on the under s‘de of the leaves, causing them to curl, and 
also becoming very abundant upon the tender terminal portion of 
the stalk and the blossom stems. A serious infestation results in 
the bloom dropping without the setting of fruit, and as this occurs 
upon the earlier blossoms the loss is frequently very considerable. 
F'gg plants and peppers are also severely affected by this pest, the 
aphids working as in the case of the tomato, on the under side of 
the leaves and the greatest injury resulting, as in the case of the 
tomato, from the attack upon the blossom and the blossom stem. 
Natural enemies. The potato aphid, like other plant lice, is 
very subject to attack by var ous natural enemies, especially minute 
four-winged parasites and the black spiny grubs and adults of the 
lady beetles. The presence of parasites in an infested field is easily 

1Ohio Agricultural Experiment Station Bulletin Belo 7 
