Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Jackson P. Audley; Crystal S. Homicz; Richard M. Bostock; Steven J. Seybold
    Date: 2020
    Source: Agricultural and Forest Entomology. 22(4): 338-348
    Publication Series: Scientific Journal (JRNL)
    Station: Pacific Southwest Research Station
    PDF: Download Publication  (521.0 KB)


    The host selection behaviour of the walnut twig beetle, Pityophthorus juglandis , was assessed by monitoring the landing rates of the beetles with sticky sheet traps on the host and nonhost hardwood branches. Sticky sheet traps were deployed for 8 weeks from 6 June to 2 August. 2017 in the Putah Creek Riparian Reserve, Davis, CA . Branches from host northern California black walnut, Juglans hindsii , were paired with branches from six nonhost hardwood species. The landing rate of juglandis (412 beetles trapped/8 weeks; 389 on host branches, 23 on nonhost branches) was significantly greater on the host branches for all nonhost hardwoods except Populus fremontii . Proportional comparisons of beetle presence also revealed a significant preference for the host branches compared with all but two nonhost species, Acer negundo and P . fremontii . Capturing P . juglandis without the use of an aggregation pheromone was a rare event, underscoring the difficulty of studying the initial phases of host selection behaviour in bark beetles. Unbaited funnel traps adjacent to selected host trees in the experiment only captured five individuals over a 19‐week period. None were captured in traps adjacent to nonhost trees. This study provided evidence that P . juglandis discriminates between host and nonhost branches while in‐flight. This directed flight behaviour is likely informed by the recognition of both host and nonhost volatile cues. This study established an ecological context for the development of a semiochemical‐based repellent system for protecting walnut trees from future attacks from this invasive bark beetl

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Audley, Jackson P.; Homicz, Crystal S.; Bostock, Richard M.; Seybold, Steven J. 2020. A study of landing behaviour by the walnut twig beetle, Pityophthorus juglandis, among host and nonhost hardwood trees in a northern California riparian forest. Agricultural and Forest Entomology. 22(4): 338-348.


    Google Scholar


    Bark beetle, coleoptera, Geosmithia morbida, host selection behaviour, Juglans hindsii, northern California black walnut, Pityophthorus juglandis, Scolytidae, thousand cankers disease, walnut pest

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page