Originally designed by Staffan Lindgren at Simon Fraser University, Lindgren Funnel Traps are the most effective and user-friendly beetle traps used worldwide. Flight appears to be triggered when ambient air temperatures exceed 65ºF (18–19ºC). 98%. The baited trap captures both sexes of the walnut twig beetle while attracting few other insect species; it includes only low numbers of most other bark or ambrosia beetles, making detection of walnut twig beetle easier. UC ANR Publication 3471, J.A. Trap Type: Pheromone Trap… In addition to the physical damage from adult and larval feeding, the walnut twig beetle also carries spores of a pathogenic fungus, Geosmithia morbida. Photograph courtesy of Jim LaBonte, Oregon Department of Agriculture. Assays 1–3 tested four compounds at variable release rates: (S)-(−)-verbenone, (R)-(+)-verbenone, racemic chalcogran, and racemic trans-conophthorin. Adult flight activity declines drastically in November. © 1996–2020 Statewide IPM Program, Agriculture and Natural Resources, University of California Regents of the University of California unless otherwise noted. Baited traps have been used primarily to detect the presence of walnut twig beetles; little information is available on how to use traps to assess the population density of the beetle. The purpose of trapping (see videos for the set up and maintenance of traps) is to detect the spread of walnut twig beetles or delimit (determine the boundaries of) a known presence of walnut twig beetle where it has been recently discovered. Although X. saxeseni resembles walnut twig beetle in size and shape, there are clear morphological differences visible under a dissecting microscope or hand lens (see Figure 21 in Detecting and Identifying Walnut Twig Beetle: Monitoring Guidelines for the Invasive Vector of Thousand Cankers Disease of Walnut for more details). Several females then join the male and create the gallery system. Walnut twig beetles colonize branches of all sizes, but generally not those smaller than 0.5 to 0.75 inch in diameter; they will successfully colonize the trunk of a tree when the trees has begun to decline. Infested wood should not be moved off-site either. There are likely two to three overlapping generations per year. The insect is present throughout California walnut orchards and in black walnut trees growing in windbreaks and surrounding riparian areas. Trapping for about six weeks from late August through mid-October or late April through mid-June, Trapping for three weeks during May and June and three weeks during September and October. codling moth), Detecting and Identifying Walnut Twig Beetle: Monitoring Guidelines for the Invasive Vector of Thousand Cankers Disease of Walnut. Symmes, UC IPM and UC Cooperative Extension Butte County (IPM facilitator), S.J. A small multiple-funnel trap is baited with the male-produced aggregation pheromone lure. Lindgren funnel trap used to sample for walnut twig beetle. Whatever the overall goal, traps must be placed near walnut trees [within 9.8 to 16.4 feet (3–5 meters) of the trunk]. Depending on available resources, more targeted detection protocols may include: A primary consideration when selecting locations for traps and choosing a density of traps in the landscape is whether the objective is to detect a new presence or delimit a known population. Other physical factors such as wind speed, light intensity, and relative humidity also appear to play a role in mediating flight. The outer bark can be peeled away to reveal walnut twig beetle galleries in the phloem, a key feature for diagnosing the thousand cankers disease complex. Predaceous beetles such as Narthecius simulator, Parandrita cephalotes, and Temnochila chlorodia, and snakeflies (Agulla) may also contribute to biological control of walnut twig beetle. Following individual assays, the most effective compounds were tested in subtractive-combination assays. Semiochemical interruption is a viable option for protecting walnut trees from P. juglandis attack. Funnel trap hung in eastern black walnut trees to detect the presence of the walnut twig beetle. Males produce an aggregation pheromone, which attracts more males and females to the colonization site and results in a mass attack. Although walnut twig beetle appears to prefer certain species of Juglans, all cultivars of English walnut seem to be susceptible to colonization by the beetle. Remove infested wood piles and prunings during the winter months in advance of the primary period of walnut twig beetle emergence and flight activity in the spring (April–June). Walnut Twig Beetle Trap II, an improved "Lindgren Style" 4-Funnel Trap. In California walnut trees, the only other related insect that might be confused with walnut twig beetle is the fruit tree pinhole borer, Xyleborinus saxeseni, which is an ambrosia beetle. When possible, burn infested material to reduce the build-up of beetle populations. This species is characterized by four to six concentric ridges on the upper surface of the pronotum (the shield-like cover behind and over the head). Sticky sheet traps … The numerous regions of necrotic (dead) tissue from gallery construction and fungal infection may overlap over time and girdle individual branches and main scaffolds, leading to branch flagging and crown decline. To view this article, download the latest version of. Numerous spores have been observed on the surface of the beetle's wing covers. Hendricks (emeritus), UC Cooperative Extension Merced County (Emeritus), W.H. Collapses for easy storage and transportation. Maximum flight occurs in May and June and then again in September and October. Male beetles bore into the bark first, creating a push-pin-sized hole in the tiny cracks and corky furrows of the otherwise smooth bark surface of English walnut. The beetle is completely dependent on walnut, butternut, or wingnut trees as hosts. Decline and mortality are more obvious in landscape black walnut trees, which are often left unattended for many years along California's rural roads and highways. Originally designed by Staffan Lindgren at Simon Fraser University, Lindgren Funnel Traps are the most effective and user-friendly beetle traps used worldwide. If walnut twig beetle is detected in traps, survey nearby walnut trees to assess the extent of the beetle infestation and symptoms of thousand cankers disease. Survey locations were within the natural range of eastern black walnut in southern and western Wisconsin and included brush disposal sites and sawmills receiving black walnut … Thousand cankers disease (TCD), is an invasive insect-disease complex caused by the walnut twig beetle, Pityophthorus juglandis, and fungal pathogen, Geosmithia morbida. Electronic versions of publications may be downloaded, printed, and distributed. Olson, UC Cooperative Extension Butte County (Emeritus), C. Pickel (emeritus), UC IPM and UC Cooperative Extension Sutter and Yuba counties (Emeritus), G.S. For a brief review of how to install and service of walnut twig beetle traps, see Quick Guide: Installing and Maintaining Walnut Twig Beetle Pheromone-baited Traps (PDF). Trees that are over- or underwatered or that have various root diseases or mistletoe infections may be more susceptible to colonization and may experience an accelerated decline. Combinations of high release rates for (R)-(+)-verbenone, trans-conophthorin, and two stereoisomers of limonene (tested in a previous study) were tested in two assays.