Toxicity, Growth, and Behavioral Effects of an Oil Extracted from Idioblast Cells of the Avocado Fruit on the Generalist Herbivore Beet Armyworm (Lepidoptera: Noctuidae)

Abstract

An oil extracted from idioblast cells in avocado fruit was examined for toxicity, growth inhibition, and behavioral effects on the generalist herbivore Spodoptera exigua (Hubner). In diet incorporation studies, the oil was toxic to both early and late instars. At concentrations of 0.80% or higher, 100% mortality was observed within 7 d. Larval weights of 3rd instars were significantly reduced after feeding for 5 d on a diet containing 0.30% oil as compared with a control diet. At lower concentrations of 0.05,0.10, and 0.20%, no significant differences in developmental times from neonate to adult emergence were observed. The oil also acted as a feeding deterrent. Choice tests initiated with neonates showed a significantly greater proportion of larvae on control diet rather than oil-containing diet for concentrations of 0.10% or greater. Similar results were obtained for choice tests initiated with 3rd instars for oil concentrations of 0.20% or greater. In these tests the larvae consumed significantly more control diet than treated diet. The potential of the oil for development as a pest management tool is discussed.