37 



Fig. 32.— Caradrina exigua: a, moth; h, larva, lateral 

 view; c, larva, dorsal view; d, head of larva; e, egg, 

 viewed from above;/, egg, from side — all enlarged {c,f, 

 after Hofmann; a-d, after Chittenden, Division of 

 Entomology). 



develop as earl}" as the last week of May and a month later in June. 

 In the cooler climate of Colorado and New Mexico larva> have been 

 noticed about the middle of June, becoming more abundant in August, 

 when the greatest damage is done. From our somewhat incomplete 

 knowledge of this species it appears that it has a spring and late 

 autumn generation in Colo- 

 rado and New Mexico, and 

 perhaps a third in southern 

 California, and it is evident 

 that the second generation is 

 generally most destructive." 

 Methods of control. — Sev- 

 eral remedies have l^een 

 employed in Colorado with 

 satisfactory results. These 

 include Paris green and kero- 

 sene emulsion, both of which 

 killed the insects and checked 

 their numbers for the follow- 

 ing 3'ear. Paris green was 

 applied as a spray and dry, 

 mixed with Hour. With flour 

 it cost about 80 cents an acre. 

 Two sprayings with the liquid preparation were most effectual. When 

 this species is unduly abundant it should lie treated in the same manner 

 as the fall arni}^ worm {Laphygma fnigiperda 

 S. & A.), which is quite often associated with in- 

 jury to sugar beet. The latter attacks nearly all 

 forms of vegetable and other crops, but as it is dis- 

 cussed fully in Bulletin 29, new series. Division of 

 Entomology, further mention is unnecessary here. 

 A third species, the true army worm {Leucania 

 unipimcta Haw.), is more strictly an enemy of 

 cereals and grasses, and not, as a rule, of much 

 importance as a beet feeder. Remedies are considered in Circular No. 

 4, Division of Entomology, and short general accounts of both the 

 true arni}^ worm and the fall army worm are furnished in Farmers' 

 Bulletin 132. 



WEBWORMS. 



Among insects that are nearly always to be found in their natural 

 habitat in fields of beets are two small caterpillars known as web- 

 worms. Of these the sugar-beet webworm is a prime beet pest, and 

 the second, known as the garden webworm, is a general feeder, devel- 



«In a more complete consideration of this species, Bui. 33, new series, Div. Ent., 

 pp. 37-46, references to economic articles by C. P. Gillette and others are furnished. 



Fig. 33. — Caradrina exigua: 

 enlarged section of first 

 proleg segment, dorsal 

 view (original. Division 

 of Entomology). 



