Re-evaluating the Economic Injury Level for Alfalfa Weevil (Coleoptera: Curculionidae) Control in Low Desert Irrigated Alfalfa

K. Harrington, Y. Carrière, A. M. Mostafa

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Alfalfa (Medicago sativa L.) dominates cropping systems in the Western United States and is first in terms of acreage planted in Arizona. The alfalfa weevil, Hypera postica (Gylenhall) and/or Hypera brunneipennis (Boheman), respectively, is the most destructive pest in terms of yield loss in low desert-grown alfalfa hay. The current economic threshold of 15-20 larvae per sweep, established in California in 1975, is currently not suitable or adopted by growers in the western U.S. low desert. Here, we conducted 4 yr of field trials to re-evaluate this economic threshold. Supporting observations of agricultural growers and professionals in the region, our results indicate that the economic threshold established in 1975 is too high. Specifically, one to three large larvae often cause a significant decrease in yield justifying weevil control based on current hay prices and costs of insecticide application. These results are discussed in the context of sustainable alfalfa production in the western U.S. low desert.

Original languageEnglish (US)
Pages (from-to)1173-1179
Number of pages7
JournalJournal of economic entomology
Volume114
Issue number3
DOIs
StatePublished - Jun 1 2021

Keywords

  • Alfalfa weevil
  • economic injury level
  • economic threshold
  • integrated pest management

ASJC Scopus subject areas

  • Ecology
  • Insect Science

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