December, '12] PADDOCK: THE SUGAR-BEET WEB WORM 441 



August. This one may prove the most destructive of the season, 

 often repeating the destruction by the July brood. The larvae of the 

 August brood enter the ground for hibernation. A few larvse, how- 

 ever, pupate and emerge as moths during the latter half of September. 

 There may be, then, three full broods and a partial fourth of this pest 

 in a season. 



Remedies. In general one could recommend, as a means of destroy- 

 ing the moths, the catching of them at night with lantern traps though 

 this must be done in the earl}^ life of the moth. The lighting of a 

 stubble field at night, adjoining the beet field, will attract the moths 

 and they will fly into the flames. We learn many interesting methods 

 employed in Europe where this pest is destructive. Few preventive 

 means have been employed in America and most are unsatisfactory as 

 the moths are not active after deposition of eggs has commenced. 



Many interesting and effective devices are used in Europe to destroy 

 the worms, but these have not proven practical under our conditions. 

 It is very important to keep the fields free from weeds. If the worms 

 are noticed in a limited area, a small stream of running water will 

 confine them. If the worms have completed their destruction, the 

 beets should be stimulated to gro^vth as quickly as possible by good 

 cultivation. In irrigated sections, the beets should be irrigated at 

 once and then cultivated as soon afterwards as possible. 



Fall plowing will, no doubt, do more than anj' other farm operation 

 to prevent an outbreak of the web worms. If a beet field has become 

 infested the ground should be well stirred in the late fall; this will 

 break up manj^ cocoons and expose the larvae to the birds and the 

 effects of freezing, also many cocoons will be buried so deeply that the 

 moths can not emerge. Crop rotation is a great aid in the control of 

 this pest and too much can not be said for clean farming methods. 



Poisoning the Worms. The worms accomplish their work of des- 

 truction so rapidly that it is very important that the beet grower should 

 be prepared to check the injuries as soon as they appear. As has been 

 said, the worms live a few days after they have finished eating and for 

 this reason much disappointment is experienced because the poison 

 is applied too late to be of any benefit. "The safe way to control the 

 pest is to poison the worms when young; the}^ are hard to kill and 

 poison must be applied in liberal doses." (Johnson.) 



The Poison to Use. From experiments conducted it would seem that 

 the best poison to use is arsenate of lead, applied either as a dust or 

 liquid spray. This is effective against the worms and does not burn 

 the foliage. If a dry spray is desired, two pounds of powdered arsenate 

 of lead per acre may be safely used. If a liquid spray is used, two 



