Antifeedant Activity of Limonin Against the Colorado Potato Beetle (Coleoptera: Chrysomelidae)

Abstract

The antifeedant activity of limonin against fourth-instar Colorado potato beetles, Leptinotarsa decemlineata (Say), was evaluated in choice and no-choice laboratory feeding assays with coated potato leaf disks. Foliage consumption was reduced 19.5, 64.4, and 67.4%, respectively, by limonin dosages of 10, 31.7, and 100 μg/cm2 in the choice tests. Consumption reduction of 64.6, 89.5, and 96.0%, respectively, with the same dosages in the no-choice tests, demonstrated increased sensitivity of the latter test condition. Conversions of the amount of foliage consumed to amount of limonin ingested indicated that greater antifeedant activity in the no-choice situation was directly related to increased limonin ingestion.