Methods of Control 409 



never find their way on the manure pile. Such 

 manure is bound to find its way back and will con- 

 taminate the soil in benches and involve later extra 

 expenses of soil sterilization. Insects and diseases 

 should never be allowed to get a strong foothold. It 

 is easy enough to destroy a few aphids for instance, 

 but it becomes a matter of greater difficulty to han- 

 dle a greenhouse which has become thoroughly in- 

 fested. No definite rules can be laid down, but 

 every greenhouse man must study his crops and his 

 conditions in order to succeed in keeping his plants 

 in the best condition of health. 



Selection of Cuttings 



With forced crops, perhaps more than with any 

 others under glass, the success of cuttings is largely 

 dependent upon proper selection. This is true for 

 instance with carnations, roses, violets or chrysan- 

 themums. It would scarcely seem possible that the 

 nature of the cutting could materially influence the 

 future plant. This, however, is a fact which has 

 been aptly mentioned by Galloway."^ It must be 

 remembered that plants, like animals, are influenced 

 by inheritance as well as by environment. In se- 

 lecting cuttings the object should be to procure those 

 parts of the plant which will transmit with the 

 greatest vigor the ability to flower or to fruit as the 

 case may be. Experienced growers will appreciate 

 this. Frequently in starting with two-rooted cut- 



* Galloway, B. T., Year Book, U. S. Dept. Agr., 247-256, 1895. 



