48 Farmers’ Bulletin 1128. 
are not satisfactory, the effort should be made to destroy the stem- 
mothers as the buds are breaking. 
CONTROL OF APHIDS ON CURRANT, GOOSEBERRY, AND GRAPE. 
All of the important aphids attacking the currant and gooseberry 
pass the winter on these plants in the egg stage, the stem-mothers 
hatching as the leaf buds are opening and soon causing the leaves 
to become more or less pitted or curled. It is especially important, 
therefore, to spray as the shoots are pushing out, to destroy the stem- 
mothers before they are protected by the distorted foliage. In spray- 
ing for these insects later in the season the liquid should be directed 
upward to wet the insects on the underside of the leaves. 
The grapevine aphis, while often abundant on the terminal growth, 
israrely very injurious. Itis much subject to parasitic and predatory 
enemies, and migrates from the grape to Viburnum in early fall. 
When so abundant as to require treatment, any of the contact in- 
secticides may be used. 
CLEAN CULTURE. 
As the reader will have learned, most aphids have a winter and 
early spring host plant, and from this they migrate to other plants, 
on which they subsist for several weeks or months during the summer. 
In most instances this alternation of food plants is essential to the 
life of the species, and in general the aphids are most troublesome 
in regions where alternate hosts are present inabundance. Often 
“se ser es 
one or more of the host plants are of little or no economic importance — 
in the locality, and in some cases are troublesome weeds. The de- 
struction of worthless plants is desirable and should serve materially 
to reduce the aphids in question. Thus, in the case of the rosy aphis, 
the alternate food plants of which are species of plantain, the destruc- 
tion of these in and about orchards is especially desirable, and should 
be a part of the remedial work against this pest in localities where it 
is more or less chronically injurious. 
O 
