INSECTS INJURIOUS TO CABBAGE AND OTHER CROPS I53 



syringe, hose or spraying machine is often of service in check- 

 ing the work of this insect. Application of remedies should 

 be made upon the first appearance of the insects. Clean cultural 

 practice should be observed. 



MAGGOT LEAF-MINERS 



The leaves of cabbage, turnip, radish and other crucifers 

 are subject to the attack of minute maggots which manifest 

 their presence by whitish blotches of larger or less extent, 



Fig. 103.— Imported turnip leaf-miner, a. Larva; b, puparium; c, adult; d, antenna of fly; 

 e, work in radish leaf. Natural size; all. others enlarged. (Reengraved after Coquil- 

 lett. U. S. Dept. Agr.) 



termed mines. If a leaf be held toward the light the maggot 

 can be seen at work between the surfaces. Four species of 

 leaf-miners commonly affect crucifers. These insects are not 

 as a rule very destructive, but they kill off leaves here and 

 there, thus weakening the plants, and rendering them more 

 liable to disease and to injury by other insects. Sometimes, 

 however, they destroy whole plants. Attack is more apparent 

 on young plants and is easily recognized. One of the commonest 



