CHAPTER VII 
INSECT ENEMIES AND THEIR CONTROL 
The insect problem demands the most careful con- 
sideration of greenhouse vegetable growers. Practically 
every greenhouse crop has one or more insect enemies. 
Some of these pests are parasites on the roots, and others 
feed on parts of the plant above ground. They cause 
enormous losses annually. The various means of con- 
trol are better understood than they were a few years 
ago, and for that reason future losses should gradually 
diminish. Success in each instance depends primarily on 
timeliness and thoroughness of application of the proper 
method of control. 
Preventive measures.—Cleanliness in the greenhouses 
and adjoining workrooms is exceedingly important in 
preventing insect depredations. The entire establish- 
ment should have a thorough cleaning annually, and 
more frequently if possible. The most propitious time 
for a complete renovation is during the summer, usually 
in August, when there are no growing crops in the 
houses. It is then possible to remove all rubbish, repaint 
the wood work, take out decayed parts of benches, and 
to thoroughly clean every part of the range, packing 
room and furnace rooms. 
Not only should a thorough cleaning be made annually, 
but rubbish which is likely to harbor insect pests should 
not be allowed to accumulate at any time under the 
benches or about the workrooms. Weeds in the houses, 
especially during the summer months, are almost certain 
to become the hosts of pests which later may develop 
into enemies of the forcing crops. It is almost equally 
important to keep the premises about the greenhouses 
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