EVALUATION OF PURE RED PERICARP AND 8 SELECTED MAIZE ACCESSIONS FOR RESISTANCE TO CORN-EARWORM (LEPIDOPTERA, NOCTUIDAE) SILK FEEDING

New sources of corn earworm, Helicoverpa tea (Boddie), silk feeding re sistance are needed to protect the maize, Zea mays L., crop without in creasing the use of pesticides. Previous evaluation of popcorn germpla sm with red pericarp color showed a high incidence of resistance. With in the National Plant Germplasm System, there are 15 maize accessions with pure red pericarp color. These 15 accessions were grown in the fi eld at Ames, IA, and Tifton, GA. Fresh silks were collected, dried, an d incorporated into a standard pinto bean diet for rearing corn earwor ms. Diets were infested with neonates, and the larvae were weighed aft er 8 d. Results of the diet testing identified four plant introduction accessions that produced 8-d larval weights equal to the resistant co ntrol, 'Zapalote Chico'. The 15 accessions were analyzed for the prese nce of maysin, three of its analogues, and chlorogenic acid. One acces sion, PI 245138, had low levels of maysin but was resistant. In additi on, eight maize accessions acquired by the National Plant Germplasm Sy stem from 1948 to 1951 were evaluated for corn earworm silk feeding re sistance at Ames and Tifton. One accession, PI 172328, was rated resis tant at both locations.