22 CIRCULAR 84 9, U. S. DEPT. OF AGRICULTURE 



Economic status. — Although one of the most common cutworms, 

 this species is rarely destructively abundant west of the Mississippi 

 River. In one instance it damaged alfalfa in eastern Kansas. 



Food plants and larval habits. — The larvae feed on a variety of 

 plants and are most commonly found in pastures and roadside vege- 

 tation. They are also prevalent in old stands of alfalfa and in sweet- 

 clover. The larvae are rather sluggish and are perhaps the least 

 pugnacious of the cutworms. 



Seasonal history. — There is a single generation of the dingy cutworm 

 annually. The eggs are deposited in the soil and on vegetation. 

 The moths are most abundant during September. This cutworm 

 passes the winter as a partly grown larva, and becomes nearly full- 

 grown by the end of March. It has a long period of inhibited develop- 

 ment in the Plains States. The larvae become inactive early in April 

 and remain in burrows until pupation begins early in August. The 

 moths begin to emerge late in August. When confined some larvae 

 failed to pupate at the normal time and remained in their burrows 

 long after field emergence was concluded. All attempts to induce 

 these individuals to pupate failed. 



Life cycle. — Eggs deposited in September hatched in 6 to 11 

 days. Most of the larvae passed through six instars, but a few molted 

 seven times before ceasing to feed. The periods required in the 

 various stages and the width of the head capsule in the different larval 

 instars were as follows : 



Period Width of head 



Stage: (days) capsule (mm.) 



Egg 5 to 13 



Instar: 



First :___ 3 to 12 0.30 



Second 4 to 12 0.40 to .50 



Third 4 to 12 .55 to .80 



Fourth 5 to 17 .80 to 1.25 



Fifth 8 to 119 1.30 to 1.90 



Sixth 15 to 169 1.90 to 2.50 



Seventh 18 to 222 2.30 to 2.80 



Eighth 83to286 



Total 249 to 351 



Pupa 12 to 35 



Egg to adult 277 to 374 



The pupa was 16 to 20 mm. long and 5 to 6 mm. in diameter. 



Reproductive capacity. — When 15 reared females were dissected, 

 the minimum number of eggs observed was 791, the maximum 1,406, 

 and the average 1,030. When 6 females taken at bait were dissected, 

 the number of their eggs ranged from 492 to 1,224, and averaged 725. 



Natural enemies. — Observations over a period of 14 years on larvae 

 collected in the field in various localities in the central Great Plains 

 are summarized in table 3. 



