44 CIRCULAR 8 49, U. S. DEPT. OF AGRICULTURE 



Diptera and 20 percent died of disease. The following parasites and 

 disease organisms were reared: 



Hymenoptera — Netelia ocellata (Vier.), Chelonus texanus Cress., Pristomerus 



{Neopristomerus) appalachianus Vier. 

 Diptera — Euphorocera tachinomoides (Tns.). 

 Disease organisms — Beauveria sp., Isaria sp., Botrytis sp., unidentified wi t. 



Heliothis armigera (Hiibner) 



Corn Earworm 

 (Figs. 2, G; 4, J) 



Distribution. — The corn earworm is distributed throughout the 

 United States. 



Economic status. — It is of major economic importance in the central 

 Great Plains and eastward and southward of that region. It is 

 perhaps the most continuously destructive species of Phalaenidae 

 found in the United States. 



Food plants and larval habits. — In the central Great Plains this 

 species is primarily a pest of corn and grain sorghums, but at times 

 extends its feeding to alfalfa, particularly in September when other 

 favored food plants are not available. In one instance it destroyed 

 approximately 2,000 acres of fall-sown wheat near Stockton, Kans. 

 This is believed to be the first record in the United States of winter 

 wheat being injured by this species. The outbreak occurred in 

 September in wheat planted in old wheat stubble, and damage was 

 most severe in weedy areas, where the predominating growth was 

 pigweed (Amaranthus sp.). Evidently at oviposition time the adults 

 had been attracted to the weeds, probably because they were the only 

 green plants available at the time. The larvae defoliated the weeds 

 and were forced to the wheat. It was apparent that the young 

 wheat plants were unpalatable and unsatisfactory as a food, because 

 the larvae did not consume the plants, but either mutilated the leaves 

 or cut off the plants at the soil surface, where they were left uneaten. 

 The larvae were much smaller than normal, and moths reared from 

 them had only about half the typical wing spread. 



Seasonal history. — -There are three generations of this species a year 

 in the central Great Plains. Normally it passes the winter in the 

 pupal stage, although Blanchard (1) reports the winter mortality to 

 be heavy. In severe winters the species probably is almost eradicated 

 from the region, and reinfestation is due mostly, if not entirely, to 

 migration of moths from more southern latitudes. 



Natural enemies. — Of 159 larvae collected from alfalfa during 

 September and October, 38 percent were parasitized by Hymenoptera 

 and 1 percent died of disease. The parasites and disease organism 

 reared were as follows: 



Hymenoptera — Microplitis croceipes (Cress.), Campoletis perdistinctus (Vier.)* 

 Disease organism — Beauveria sp. 



Heliothis phloxiphaga Grote and Robinson 



Distribution. — This species is recorded as being widely distributed 

 in the United States. 



Economic status. — It is of no economic importance in the central 

 Great Plains. 



