2i6 DISEASES OF THE SWEET PEA 



PRINCIPLES INVOLVED IN SPRAYING 

 SWEET PEAS 



It should be remembered that to destroy 

 chewing insects such as caterpillars, etc., 

 the stomach poison must be evenly dis- 

 tributed all over the plant. This should 

 be done as soon as the presence of the pest 

 is suspected. Intelligent and observant 

 growers will, of course, remember the time 

 of appearance of the pest every year, al- 

 though the time depends somewhat on the 

 climate of each season. In destroying the 

 green aphids the contact poison should be 

 distributed as evenly as possible on the in- 

 sect itself. It is, therefore, best to spray 

 for aphids as they are actually found 

 working on the plants. With chewing in- 

 sects and with fungous pests, however, the 

 applications are made even before the par- 

 asites appear. Before spraying it is nec- 

 essary to have well in mind the organism 



