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 



103 



