OTHER ENEMIES OF CELERY 247 



The Carrot Beetle. This is a brown scarabid beetle (Ligyrus 

 gibbosus DeG.), a little more than one-half an inch long. It 

 works upon carrots, celery, and parsnips, and also attacks corn, 

 potatoes, and other crops. Adults are found attacking the crown 

 or root of the plant below the surface. They are sometimes present 

 in large numbers in a field of root crops. The work may be nearly 

 destroyed without injuring the top of the plant. The larvae re- 

 semble in miniature the familiar " white grub." 



Control. Rotation of crops and fall plowing are the standard 

 remedies. Hogs and chickens allowed to run in the infested field 

 after the removal of the crop will lessen their numbers materially. 

 Some success has been attained in combating other members of 

 this family (Lachnosterna and allied genera) by the use of a lantern 

 trap, to which they are attracted, early in the season before egg- 

 laying begins. Manifestly such traps would be of little service 

 after that period. 



The Celery Caterpillar. The adult of this insect is the common 

 black, swallow-tailed butterfly (Papilio polyxenes Fab.). The 

 caterpillar itself is green or yellow, with black stripes, having re- 

 tractile yellow horns placed a short distance back of the head. 

 These horns are extended when the caterpillar is disturbed. In 

 the northern states the winter is passed in the chrysalid (pupal) 

 stage, the butterflies appearing in May. Eggs are laid on the foliage 

 and hatch in from four to nine days. The young caterpillars are 

 nearly black, with a white band around the middle of the body. 

 The complete life cycle requires about eight weeks. 



The caterpillars feed on the foliage and undeveloped seed of 

 almost all umbelliferous plants, including celery, parsnip, caraway, 

 parsley, fennel, dill, and wild carrot, wild parsnip, as well as the 

 garden carrot. 



Control. Hand-picking is often all that is necessary. Spraying 

 or dusting with arsenicals may be best for large areas if the insects 

 are very numerous. 



The Carrot Rust Fly (Psila rosce Fab.). Celery leaves some- 

 times turn a reddish color, due to the attacks of this small insect, 

 which belongs to the order Diplera, or two-winged flies. The 

 roots are also discolored by the maggot which is often found in the 

 roots of carrots. Clean cultivation after cropping is recommended, 

 as well as rotation of crops. Celery should not follow carrots. 



Other Enemies of Celery. Wire worms of several species 

 sometimes injure celery, as does also the tarnished plant bug. 



