Sunflower Beetle (Coleoptera: Chrysomelidae): Pattern of Larval Distribution and Parasitism in Cultivated Sunflower Fields

Authors

Gary J. Brewer, University of Nebraska-LincolnFollow
Laurence D. Charlet, USDA, ARS, Northern Crop Science Laboratory

Date of this Version

2004

Comments

Published in JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY 77(1), 2004, pp. 21–25.

Abstract

The sunflower beetle, Zygogramma exclamationis (Fabricius), is a major pest of commercial sunflower, Helianthus annuus L. (Asteraceae), in the Plains area of central North America. Although an economic injury level for the sunflower beetle has been determined, in-field distributions of the larvae and their natural enemies have not been described. Over a three year period, fields were sampled for sunflower beetle larvae and for larvae of the endoparasitoid, Myiopharus macellus (Reinhard). Sunflower beetle larvae were generally found to have aggregated distributions. Knowledge of the distribution pattern will allow the development of more efficient sunflower beetle sampling protocols. Parasitism rates of M. macellus throughout fields were equivalent, indicating effective host searching. Although the data supports aggregated distributions for M. macellus, it is less clear than that for the sunflower beetle.