Economic Injury Levels for Western Bean Cutworm, Loxagrotis albicosta (Smith) (Lepidoptera: Noctuidae), Eggs and Larvae in Field Corn

Authors

Larry L. Appel, Appel Crop Consulting, Grant, NE
Robert J. Wright, University of Nebraska-LincolnFollow
John B. Campbell, University of Nebraska-LincolnFollow

Date of this Version

1993

Citation

JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY 66(4), 1993, pp. 434-438

Abstract

Yield losses caused by different densities of western bean cutworm, [Loxagrotis albicosta (Smith)], egg masses and young larvae in field corn [Zea mays(L.), Pioneer 3475] were studied in replicated field cages in Perkins County, Nebraska, during 1989 and 1990. Treatments consisted of four egg masses per plant, one egg mass per plant, ten young larvae per plant, three young larvae per plant and an uninfested caged check. Infestations were timed to correspond with the natural occurrence of western bean cutworms each year. Larval density at dent stage and total grain yield were measured. Linear regression equations were calculated to describe the relationship between larval density at dent stage and total yield. Yield losses during the two years averaged 3.7 bu/acre for each western bean cutworm larva per plant at dent stage. Average survival to mature larvae in the field cages during the two years was 3.3 ± 0.4% for eggs and 21.6 ± 2.1% for young larvae. Economic injury levels for western bean cutworm egg masses and young larvae are presented.