I08 INSECTS INJURIOUS TO VEGETABLES 



METHODS OF CONTROL 



Owing to the difficulty of destroying root-maggots and the 

 cost of the chemicals, growers depend largely upon methods of 

 prevention which should be employed before the insect's eggs 

 are laid. 



Sand and kerosene, for deterring the parent flies from de- 

 positing their eggs, consists in placing sand soaked in kerosene 

 — a cupful to a bucket of dry sand — at the base of the plants, 

 along the rows. This will also kill young maggots that might 

 attempt to work through it. 



Mineral fertilizers are useful as deterrents, if employed just 

 before or after a shower has thoroughly wet the ground. The 

 principal fertilizers for the purpose are kainit, nitrate of soda, 

 and chlorid of potash. They are used as top dressings before 

 planting ; and afterwards, when they should be applied as nearly 

 as possible to the roots, the earth being turned away from the 

 plants for this purpose. These fertilizers possess the advantage 

 of acting also as a stimulant to plant growth, thereby facilitating 

 recuperation from root-maggot attack. 



Danger from organic fertilizers. — Stable manure and organic 

 fertilizers are apt to induce infestation, since this species devel- 

 ops in excrement and other decomposing material. Numerous 

 instances of this have come to the writer's knowledge. It is 

 advisable,, therefore, to avoid the use of manure, rotted leaves, 

 or other organic fertilizers, and to avoid planting in fields in 

 which there have been infested or diseased plants. 



Hellebore is used with some degree of success in Canada as 

 a remedy for the cabbage and onion maggots. 



Carbolic acid emulsion diluted about 35 to 50 times, is partic- 

 ularly applicable when this species occurs in radish and other 

 plants than cabbage and cauliflower. 



Hand-picking, although laborious, has the merit of effective- 

 ness and has been practiced with much success by extensive 

 growers. It consists in lifting out the young plants, examining 



