Abundance, Age Structure, and Voltinism of Light Brown Apple Moth Populations in California

• Published in: Environmental entomology Vol. 40; no. 6; pp. 1370 - 1377
• Main Authors: Buergi, L. P, Roltsch, W. J, Mills, N. J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Entomological Society of America 01-12-2011; Oxford University Press
• Subjects: Abundance; Age; Age composition; age structure; Animals; Arctostaphylos; Arctostaphylos densiflora; Biological and medical sciences; California; degree-days; Epiphyas postvittana; Fundamental and applied biological sciences. Psychology; heat sums; Insect Control - methods; insect larvae; instars; invasive species; Larva - growth & development; Larva - physiology; Larvae; Leptospermum; Leptospermum laevigatum; Light effects; Malus; Models, Biological; monitoring; Moths - growth & development; Moths - physiology; Pests; Phenology; Phytopathology. Animal pests. Plant and forest protection; Population Dynamics; POPULATION ECOLOGY; Protozoa. Invertebrates; Pupa - growth & development; Pupa - physiology; Records, symptoms, damages, economic importance, population surveys; Seasons; summer; Voltinism; winter; Australia; California; United States; North America; America; INE, USA, California, San Francisco; INE, USA, California, Santa Cruz; degree-days; invasive species; phenology; Epiphyas postvittana; Insecta; Rosaceae; Population structure; Malus domestica; Tortricidae; Invasive species; Pest; Voltinism; Phenology; Arthropoda; Dicotyledones; Angiospermae; Lepidoptera; Spermatophyta; Fruit tree; Invertebrata; Age; Population density
• ISSN: 0046-225X; 1938-2936; 0046-225X
• DOI: 10.1603/EN11165

The light brown apple moth, Epiphyas postvittana (Walker), is native to Australia and first was detected in California in 2006. In this study, we regularly sampled populations on Leptospermum laevigatum (Gaertn.) F.Muell. at two sites in San Francisco and on Arctostaphylos densiflora M.S. Baker at two sites in Santa Cruz over a 2-yr period to monitor the abundance, age structure, and voltinism of this potential pest in relation to degree-days. Our results showed that larval abundance declined at two sites, cycled with peaks in midsummer at one site, and remained steady at one site. Generations overlapped at all four sites with the full range of larval instars being present for most of the year, although populations during the winter were predominantly mid to late instars. Accumulated degree-days predict an average of 3.27 and 4.58 generations per year in San Francisco and Santa Cruz, respectively, which matched our observed peaks of late-instar larvae in the field remarkably well. This new information on light brown apple moth phenology in coastal California will be invaluable for the development of effective monitoring and management strategies for this new invader in the studied region.