12 



in the hands of a man who will use it soon enough, often enough 

 and thoroughly enough, it may do all that could he reasonably 

 expected ; but applied too late, after the insects are already work- 

 ing in the plant tissue, or not often enough to reach all the speci- 

 mens as they develop, or in such manner as not to reach all or any 

 of them, and the result is bound to be disappointing. 



And even the character of the soil may cause some difference, 

 because in a light, loose or sandy soil materials may penetrate 

 readily and reach the maggots, where in a heavy, compact or clay 

 ground it would not be more than a surface wetting. 



The elements of time, frequency and thoroughness of applica- 

 tion are all of the highest importance, and the neglect of any one 

 of them will impair the effectiveness of whatever measure is used. 



Stomach poisons are entirely unavailable, apparently, and the 

 ])lants themselves and their susceptibility to injury must be con- 

 -iilered in the selection of materials: the mineral oil emulsions, 

 f<»r instance, which are excellent contact poisons, are even more 

 fatal to the plants than to the insects. 



Premising this, our discussion of remedial measures will narrow 

 itself to those cultural and preventive methods and destructive 

 ujiplications which have been more or less effective in our own 

 1 Kinds in actual practice in the State or in other States, as pub- 

 ]i>hed in their reports and bulletins. 



CULTURAL METHODS. 



While those are not so directly useful against the onion maggot, 

 t xcept in so far as it is advisable to remove all plants in which the 

 iii-eets are found, whenever that is possible, they are of consider- 

 able importance in controlling the cabbage maggot. As has al- 

 ready been stated, this insect M'ill breed on the wild as well as the 

 cultivated cruciferous plants, and hence all the former, including 

 ~ome of our most common weeds, such as hedge mustard, winter 

 rress. etc., should be destroyed so far as possible. It has also been 

 pointed out that some of the insects may hibernate in the puparium 

 st^'ge on or near the roots of the plants on which the maggots have 

 been feeding; therefore, remove all roots as soon as they are no 

 longer useful and destroy them with all their contents. Cabbage 

 stumps should be pulled, carried off and dried out or burnt as soon 



