Sampling Methods, Economic Injury Levels, and Economic Thresholds for the Russian Wheat Aphid (Homoptera: Aphididae)

Abstract

<i>The Russian wheat aphid</i>, Diuraphis noxia <i>(Mordvilko), is a major pest of wheat and barley in the central Great Plains and western areas of the United States. When the Russian wheat aphid was first detected in the United States, researchers and extension personnel coordinated their efforts to develop methods by which its spread could be detected. Sampling methods also were developed to help producers and researchers determine the level of Russian wheat aphid infestation in specific fields. Parallel efforts were made to determine economic injury levels and economic thresholds, which were used to determine if emergency insecticide applications can be justified. This paper discusses that part of the Russian wheat aphid response model which involved the development and use of aphid surveys, sampling methods, and economic injury levels and thresholds. It begins with a discussion on the need to conduct a thorough literature search on sampling, injury levels, and thresholds. It then proceeds through the methods that were used to identify and develop survey and sampling methods, as well as economic injury levels and thresholds for the Russian wheat aphid. It ends with a short discussion on some potential directions for sampling methods and threshold work.</i>