92 CELERY CULTURE 



celery fields. Hand picking has been found satis- 

 factory for keeping this insect under control, but 

 should they become very numerous it may be neces- 

 sary to trap the moths by means of open lamps at 

 night. Spraying with arsenites might be practiced 

 in cases where the larvae have become very plenti- 

 ful, but the solution should be so applied as to cover 

 the under side of the leaves where the insects feed. 



The Celery Caterpillar (Papilla asterias). This 

 is the most conspicuous of the celery insects, and 

 perhaps the most harmful. It feeds upon the leaves 

 and a single larva will strip the foliage from a plant 

 in one or two days. Owing to its size and yellow 

 color, with black transverse bands, it is easily seen 

 against the background of green leaves. The celery 

 caterpillar does not appear in large numbers and 

 hand picking will control it. 



The Zebra Caterpillar (Mamestra picta) 1 . This 

 insect is much smaller than the regular celery cater- 

 pillar but fully as striking in appearance. It is often 

 quite abundant, but is easily recognized and can be 

 controlled by hand picking. 



The Tarnished Plant-bug (Lygus pratensis) 1 . 

 This insect is quite small while young, being about 

 one-twentieth of an inch in length, of a yellowish 

 green color, which changes to a faded yellow or a 

 dull brown when fully grown. As a preventive, keep 

 the celery well cultivated and free from weeds. In 

 the autumn remove all trash from the soil under 

 which the insects can pass the winter. A good rem- 

 edy in addition to frequent clean cultivation is kero- 



1 U. S. Dept. of Agr., Bureau of Entomology, Bui. No. 43. 



