APHIDS 
STRAWBERRY 
The Strawberry Root Aphis 
Aphis forbesi Weed 
This species is very destructive to 
strawberry plants in the eastern and mid- 
dle western states. The lice, which are 
greenish-black and about one-twentieth 
of an inch long, cluster in great numbers 
on the larger roots. The winter eggs 
are laid above ground but the lice work 
chiefly under the.surface of the ground 
and are especially troublesome in light 
soils. In the control of this aphis sev- 
eral points should be noted: First, 
plants should not be set out on land in- 
fested within the two years previous, as 
infested roots were probably left in the 
soil when the plants were pulled up and 
these remain infested for months; second, 
plants to be set out, if infested, may be 
disinfected by being dipped in diluted 
tobacco extract, provided the winter eggs 
have hatched; third, straw burnt over 
the beds just as the plants are beginning 
to grow in spring will destroy eggs and 
lice on the leaves and stems. Several 
species of plant lice occur occasionally 
on the leaves of the strawberry. These 
can be destroyed by any of the contact 
insecticides suggested for the Green Apple 
Aphis. In Europe Schizoneura fodiens 
Buckt. infests the roots of the straw- 
berry. 
BLACKBERRY AND RASPBERRY 
The Blackberry Aphis 
Amphorophora rubi Kalt. 
This is a large pale green louse with 
dilated cornicles. It is a HEuropean 
species and occasionally colonizes the 
growing shoots of blackberries and rasp- 
berries in spring. Its life history is not 
well Known. It may be controlled by 
spraying with whale-oil soap 1 pound to 
6 gallons of water. 
WALNUT 
The European Walnut Aphis 
Chromaphis juglandicola Kalt. 
This is a small lemon-yellow species 
occurring on nuts and leaves of the 
European walnut. Its life history is 
similar to that of the Green Apple Aphis 
o1 
ca 
except that the agamic or viviparous lice 
are all winged. The winter eggs are 
often laid in crevices of the bark and 
are thus not easily reached by spraying. 
The lice on the leaves can be controlled 
by spraving with a combination spray 
of dilute oil emulsion and tobacco ex- 
tract (Black Leaf “40”, 1-1,600, or Black 
Leaf 1-100). 
CHESTNUT 
The Chestnut Aphis 
Callipterus castaneas Buckt. 
This species infests the leaves of com- 
mercial chestnuts. In appearance and 
habits it greatly resembles the walnut 
louse. Doubtless it can be controlled in 
a similar manner. 
CITRUS TREES 
In America five species of plant lice 
are found on citrus fruits. They are (1) 
the Citrus Aphis (Toxoptiera aurantiae 
Koch); (2) the Cotton Aphis (Aphis 
gossypii Glover); (3) Aphis cookii Essig; 
(4) the Green Peach Aphis (Myzus persi- 
cae Sulz.); (5) Macrosiphum citrifolti 
Ashm. The first three of these are small 
dark brown or black insects while the 
last is a larger pale green form. The 
Green Peach Aphis will be found de- 
scribed under the article on Peach plant- 
lice. Occasionally one or more of these 
lice become abundant on the tender 
growth of citrus foliage and may do much 
injury to young buds. As far as citrus 
trees are concerned the life histories of 
these species have not been entirely 
worked out. 
Control 
Whale-oil soap, 1 pound to 6 gallons of 
water, 7 per cent kerosene oil emulsion, 
soap and dilute tobacco extract, or car- 
bolic acid emulsion (diluted so that about 
1% gallons crude carbolic acid is used 
to 200 gallons of water) will be found 
effective washes for citrus plant-lice. A 
second application may be necessary 
about four days after the first in order 
to insure the complete control. High 
pressure is requisite except for young 
puds, which should be sprayed with a 
knapsack or bucket-pump as pressure will 
knock them off the tree. 
