Vegetable Growing in Colorado. 
45 
Striped Cucumber Beetle (Diabrotica vittata). 
This is one of the oldest and best known enemies of melon and 
cucumber vines. The adult insect is a small yellow beetle with 
three narrow black lines upon the back, or wing covers. It is very 
similar in appearance to the corn rootworm mentioned above, but 
shows the stripping much more plainly than that insect. The beetles 
usually appear about as soon as the second leaves start upon the 
cucumber plants. They often come in a single day in sufficient 
numbers to destroy the plants. The beetles have the habit of going 
in swarms, so that they often destroy certain hills completely with¬ 
out attacking others. While this insect is not generally distributed 
in Colorado, it has become rather abundant in the melon growing 
sections of the southeastern portion of the state. 
Remedies .—Insecticides are often of little avail for the control 
of this insect. Pyrethrum powder, when thoroughly dusted over 
the plants early in the morning, while the insects are still dormant, 
will usually give good results. The plants should be disturbed 
enough to cause the insects to drop to the ground, so the powder 
can be thoroughly applied to them. Any very fine powder, such 
as fine road dust, ashes, slaked lime and the like, when thoroughly 
applied to the plants, will help some to reduce the injuries of this 
beetle. The application of arsenical poisons will do some good, 
but is seldom very efficient. The beetles may be kept away from 
the plants by putting mosquito netting over the vines and holding 
it down by means of dirt, stones, or wooden pegs. 
Wherever this insect is abundant, it is advisable to plant plenty 
of seed, so that many of the plants may be sacrificed and still enough 
remain to produce a crop. \ 
ONIONS. 
The Onion Thrips. 
The onion thrips, sometimes spoken of as a louse, is a very 
minute, active insect that commonly attacks onion tops in Colorado, 
causing them to turn white, and often to wilt and fall to the ground. 
This insect is so small that it is often overlooked by the gardener, 
even when it is present in large numbers. When fully grown these 
minute insects have wings and will readily fly from the plants when 
disturbed, which makes it somewhat difficult to apply insecticides 
effectively. 
Remedies .—The onions should be closely watched and when 
grayish or whitish places begin to appear upon the tops, it is quite 
certain that this insect is present and beginning its injuries. If the 
tops seem to be bleaching rapidly, it is advisable to apply some in¬ 
secticide for the destruction of this insect. The best remedies are 
either some strong tobacco extract, such as Black-leaf 40, in the 
