168 



Principles of Plant Culture. 



or pine tar, is said to prevent the entrance of the round- 

 headed borer (306). Protecting the trunk with straw or 

 lath, as recommended to prevent sun-scald (186), may 

 tend to keep out these insects. Borers in the trunk can 

 often be destroyed by probing their holes with a flexible 

 twig. 



3f2. Leaf-Miners often infest spinach and beets grown 

 for greens, rendering the leaves unfit for use. For these 

 insects we can offer no preventive measures of 

 established value. The application to the 

 young foliage of powerful odorants, as coal-tar 

 water or a solution of carbolic acid, may prove 

 beneficial. 



313. The Codling-Moth,* which causes so- 

 called ' i wormy ' ' apples and pears, is controlled 

 by spraying the trees at the time of egg de- 

 posit, with water containing Paris green (285). 

 The first spraying should be 

 given as soon as the petals 

 (143) fall, to be followed by a 

 second six to 

 ten day slater. 

 If much rain 

 falls at this 

 season, the 

 sprayings may 

 need frequent 

 repetition. A 



FIG. 74. 



Fig. 73. Card of tarred paper, for placing about the 

 stems of young cabbage and cauliflower plants. Re- 

 duced one-half. 



Fig. 74. Tool for cutting the cards. 



Fig. 75. Manner of using the tool. The dotted lines 

 drop of poison- show the position of the edge of the tool on the paper. 



ed water should be lodged in the calyx (142) of every 

 fruit, and as this evaporates, the poison deposited on the 



Carpocapsa pomonella. 



