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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



and fourth instars, although some had already pupated and there were 

 many that were still very small. The larvae were at the height of 

 their abundance on June 15 and continued in diminishing numbers 

 through the first week in July. From pupae collected in the field on 

 June 10, moths emerged June 25, other moths reared from the first 

 brood of worms emerged as late as July 30. 



A second brood of laryae was expected in late July or early August 

 but so abundant were insect parasites and a bacterial disease that no 

 more larvae were observed at any time during the remainder of the sea- 

 son. Several adults were taken in the Gallatin Valley during the first 

 week in September. 



Plants Attacked and Nature of the Injury 



Sweet clover {Melilotus alba Lam.) was the favorite in a long list 

 of plants fed upon the larvae. Sweet clover plants standing in the 

 midst of alfalfa were generally stripped bare of all foliage, while sur- 

 rounding alfalfa plants were only partially defoliated. Alfalfa was 

 second only to sweet clover and because of its much greater abundance 

 was the plant by far the most generally attacked. When gardens were 

 invaded lettuce was most severely attacked and wild lettuce {Lactuca 

 pulchella D. C), was stripped to the stems wherever the loopers were 

 abundant. 



Larvae were seen feeding upon the following hosts: Sweet clover, 

 alfalfa, red clover, white clover, alsike clover, flax, sugar-beets, corn, 

 lettuce, carrots, onions, peas, beans, cucumbers, muskmelons, water- 

 melons, squash, currants, gooseberries, raspberries, dock (Rumex 

 crispus L.), wild lettuce {Lactuca pulchella D. C), lamb's-quarters 

 (Chenop odium album L.) and sunflower {Helianthus sp.). From 

 Idaho, Mr. Parks reports the larvae as feeding upon apple foliage. 



Grains and grasses were never attacked even where adjoining heavily 

 infested alfalfa fields. Sometimes the larvae would crawl to such crops 

 for the purpose of spinning their cocoons. 



The first crop of alfalfa was nearly ready for cutting when the looper 

 larvae began to attract attention. In most instances the injury was 

 not noticeable from a distance, but upon close examination it could be 

 seen that a large percentage of the leaf area had been destroyed. 

 Where the infestation was heaviest, fields presented a whitened ap- 

 pearance quite similar to characteristic alfalfa weevil injury. It is 

 hard to state the amount of the injury to alfalfa as very few farmers 

 make a practice of weighing their hay each year. However, on the 

 Bureau of Plant Industry farm at Huntley, where careful records of 

 the weights of all crops are made each year, it was found that the yields 

 from the first cutting were approximately one-half ton less per acre 



