INJURIOUS TO CARROT AND RELATED CROPS 183 



works its way down along the root and at first feeds on the 

 tender tip. 



In the case of carrots and parsnips, the maggots at first feed 

 on the tip of the tap-root and later the whole root is riddled 

 with burrows which run in every direction. These burrows 

 are of a rusty color, hence the common name of the insect. 

 When badlv infested, the carrot roots decay and when one 



Fig. 104. — Two celery plants injured by the carrot rust-fly and an unin- 

 jured plant of the same age. 



attempts to pull them the lower part will break oflF and remain 

 in the ground (Fig. 10.3). The outer leaves of infested plants 

 soon turn yellowish and the whole top may wilt down and die. 

 The injury to celery is of a somewhat different nature. 

 Here the fibrous roots are eaten off and destroyed. Infested 

 plants take on a sickly whitish color and remain stunted. The 

 plants are often able to throw out a new set of fibrous roots 

 near the surface of the ground and can thus outgrow the injury 



