APHIDS 47 
generation will be winged and migrate 
to other trees, but the great majority 
will be wingless and remain to colonize 
the growing shoots. These develop in 
from 14 to 20 days and when mature im- 
mediately deposit young. The lice of the 
third and subsequent generations during 
the summer season develop in 10 days. 
Sometimes winged and sometimes wing- 
Fig. 2. Winged Viviparous Female of Green 
Apple Aphis. Enlarged. 
less forms predominate in the summer 
generations, most of the former migrating 
to other trees. These generations are all 
parthenogenetic, that is, the females give 
birth to their young without the pres- 
ence of the male element. The young in 
this case are born alive, or viviparously. 
There may be from 10 
to 16 such generations 
inasingle season. 
About the time of the 
first frosts in the fall 
appears the sexual gen- 
eration consisting of a 
wingless male and a 
wingless egg-laying or 
oviparous female. The 
males are smaller than 
the other forms of this 
louse, and are of a yel- 
lowish-brown color with 
dusky appendages and 
cornicles. The sexual 
_ females resemble in size 
and general appearance 
the wingless summer 
forms, but they are dull 
green with a tinge of 
rusty yellow. The sexes 
occur mostly on the un- 
der side of the leaves. 
They mate and the fe- 
male then lays three 
=——e or four greenish eggs 
Fig. 3. Eggs of Green on the smaller limbs of 
Apple Aphis on Ap- : 
ple Twig. the tree, generally in 
the crotches of the twigs or at the base 
of a next-year’s bud. Ina day or two the 
egg turns a shining jet black. 
The summer lice vary considerably in 
size and in the green shade of the body. 
The average length of the body of the 
wingless viviparous lice is 1.75 mm., 
while that of the winged lice is 1.55 mm. 
The average egg measurement is .60x.25 
mm. 
Injury 
The Green Apple Aphis attacks leaves, 
young shoots and fruit. When abundant 
the lice curl the leaves badly and greatly 
reduce the size and marketable value of 
the fruit. 
Control 
This species can be controlled most 
easily by the application of winter washes 
directed against the winter eggs. Home 
made lime-sulphur, using the 1-1-3 for- 
mula, commercial lime-sulphur 1 to 8 
or 1 to 10, or a 12 per cent. crude oil 
emulsion will be found satisfactory as an 
ovicide. The winter spray should be ap- 
plied as late as possible before the buds 
open, as the best results accrue when the 
trees are sprayed just before the buds 
begin to open. Against the lice on the 
foliage spraying should be done directly 
the lice have all hatched and before they 
have had time to curl the leaves. Once 
the leaves have been curled it will be 
very hard to destroy the lice on them. 
Whale-oil or fish-oil soap 1 pound to 5 
gallons of water, kerosene emulsion 7 per 
cent, or diluted tobacco extract (Black 
Leaf ‘40” 1-1,200, Black Leaf 1-80) is ef- 
fective. Good pressure is a requisite for 
the spring applications. Pruning the 
twigs in winter will destroy a large 
number of the eggs. 
The Rosy Apple Aphis 
Aphis sorbi Kalt. 
This species occurs on the apple all 
over the United States. In Europe, its. 
original home, it infests also wild apples 
(Sorbus spp.) and hawthorns. Its life 
history is not fully known. The stem- 
mother lice hatch at about the same 
time as the leaves open out in the spring. 
They feed on the under side of the leaf 
and very soon cause it to curl around 
