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VEGETABLE GARDENING 
as the cabbage louse, has been known in America for 
over a century, and has become disseminated throughout 
the country. Its destructiveness varies greatly from 
year to year, depending upon seasonal conditions and the 
prevalence of natural enemies. Protracted drouth un- 
questionably favors the multiplication of this pest, while 
low temperatures with heavy rainfalls are unfavorable. 
This insect usually appears in the North the latter 
part of May or early in June, and feeds upon both upper 
and under sides of the leaves, which they cause to curl. 
The pest multiplies with marvelous rapidity, producing 
from a dozen to a score of broods in a season. (Bulle- 
tin 2, Virginia Truck Experiment Station, Norfolk, Va.) 
The bodies of the mature forms are green, but are cov- 
ered with a grayish, powdery coating, which at a dis- 
tance gives the appearance of mildew. The young are 
ready to reproduce in five or six days. 
The eggs, which pass the winter attached to the stems 
and the refuse leaves, give rise to the first broods next 
spring. This suggests the most effective means of pre- 
vention: all refuse in infested fields should be destroyed 
in the fall. It is also important to destroy remnants of infested 
plants from which the summer crop has been harvested. 
Dusting the growing plants with various forms of to- 
bacco dust is proving effective in many sections. One 
brand containing 6 per cent nicotine sulphate has given 
complete control of the cabbage aphis in California. 
Spraying with kerosene emulsion, diluted to 15 parts, 
or with one of the many commercial tobacco preparations, 
is a satisfactory means of controlling the insect on grow- 
ing plants. The first application should be made before 
the infestation becomes general. A knapsack sprayer, 
with the proper nozzle and extension attachments, may 
be used to advantage in spraying isolated plants and 
small plantations. It is important that the material be 
applied to the underside of the leaves as well as to the 
