90 Gardening Under Glass 



methods must be used to control these two differ- 

 ent classes of pests. Evidently, the kind which 

 eats can be poisoned by putting poison on their 

 food. It is equally evident that poison applied 

 to the surface will have no effect upon the kind 

 that sucks the juices from beneath the surface. 

 These are the first two things to learn in the war 

 on insect pests, 



Now, in any general seed catalogue you will 

 find a half-a-dozen or more things for poisoning 

 chewing insects, but a good arsenate of lead, or 

 calcium arsenate, is the one thing needed. A 

 half pound of either of these will take care of 

 your indoor garden for many months. 



Sucking Insects Cause the Most Trouble 



It is the sucking insect which causes by far 

 the greater amount of trouble with plants under 

 glass. As these cannot be poisoned, it is neces- 

 sary to take care of them with some insecticide 

 that will kill by contact. The most convenient 

 and effective thing I have ever found is a strong 

 nicotine extract — 40 per cent, nicotine sulphate. 

 Of course, a "contact" spray must come into di- 

 rect contact with the insect in order to be effec- 

 tive. This cannot be applied in advance and 

 left, but must be sprayed directly upon the pest. 



On a bench full of plants, or where vegetables 



