The UKc of mineral fertilizers. — Mineral fertilizers are useful as deter- 

 rents, particular!}' when employed just before or after a shower has 

 tlioroughlj' wet the ground. The principal fertilizers for this purpose are 

 kainit, nitrate of soda, and sulphate or chlorid of potash. They niaj^ be 

 used as top dressings before planting; or, if not emploj^ed until after- 

 wards, they should be applied as nearly as possible to the roots, the 

 earth being turned awaj'' from the plants for this purpose. These ferti- 

 lizers possess the advantage of acting also as a stimulant to plant 

 growth, thereb}' facilitating recuperation from root-maggot attack.^ 



Danger from use of organic fertilizers. — Stable manure and organic; 

 fertilizers are apt to induce infestation, since the species under consider- 

 ation is well known to develop in excrement and other decomposing 

 material. Numerous instances of this have come to the writer's knowl- 

 edge during recent years. 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. 



Hand methods. — As soon as seed fails to appear at the proper time or 

 the plants show signs of wilting and maggots are found to be present, 

 the seed may be hoed out or the injured plants pulled and destroyed, 

 together with the young maggots. 



Most of the methods mentioned above have been used with success 

 against onion maggots and other root-feeding species, and are all that 

 is required in manj^ cases of ordinary infestation of vegetable roots. 



THE CABBAGE MAGGOT. 

 {Pegomya hrnssica; Bouche.) 



Cabbage and related cruciferous crop plants frequentlj' suffer severe 

 injury from the attack of the cabbage maggot. Young plants are most 

 seriously affected, the maggots eroding the outer surface and boring 

 into the interior of the roots, devouring the tender rootlets and 

 frequently penetrating into the lower portion of the stalk. 



This insect, known also as the radish maggot, is an imported pest, 

 and was first noticed ruining cabbage, cauliflower, and similar plants in 

 New York State about half a century ago. It does most serious injury 

 throughout the northern tier of States and Canada, attacking all forms 

 of crucifers, whether wild or cultivated. In that region it is the cause 

 of more or less loss to these crops year after year, but as with other 

 destructive insects, it is much more abundant in some seasons than in 

 others. Since 1902 it has not only been exceedingly destructive, but 



'It is frequently necessary to use these fertilizers in large quantities. In cab- 

 bage fields a fertilizer of the proper composition is applied before planting at the 

 rate of 1,000 to 1,500 pounds to an acre. After the plants have started growth, 

 a top dressing of 100 pounds of nitrate of soda and 2(K1 pounds superphosphate 

 is added. When the heads are beginning to develop, a third application of 

 about 200 pounds of nitrate of soda to the acre is often desirable. For details 

 consult Voorhees's "Fertilizers." 



