Walnut twig beetle trapping yields insights for monitoring secondary pest Scolytinae in Tennessee

2016 ◽  
Author(s):  
William Klingeman
Author(s):  
Matteo Marchioro ◽  
Massimo Faccoli

AbstractThe Walnut Twig Beetle (WTB), Pityophthorus juglandis Blackman, is a small bark beetle native to Mexico and Southwestern USA recorded for the first time in Europe (NE Italy) in 2013. WTB attacks walnut (Juglans spp.) and wingnut trees (Pterocarya spp.) and is the vector of Geosmithia morbida Kolarík et al., a pathogen causing the thousand cankers disease (TCD). WTB and TCD represent a serious threat for walnut orchards in Europe. Spatiotemporal data of the WTB-TCD infestations recorded from an 8-year-long (2013–2020) monitoring conducted in 106 walnut orchards of NE Italy were used to develop a model in order to analyze: (i) the effective dispersal capacity of WTB, (ii) the factors affecting dispersal and (iii) the colonization risk of healthy walnut orchards. We registered a mean annual dispersal of 9.4 km, with peaks of about 40 km. Pest dispersal is affected by distance of suitable hosts from the nearest infested site, number of walnut orchards in the surroundings (both infested and healthy), orchard size and walnut species in the orchard. Using the model, it was also possible to calculate the colonization risk of a specific walnut orchard according to its characteristics showing, for instance, that a medium-size (5,000 trees) black walnut orchard located at 25 km from the nearest infested orchard has an infestation risk of about 50% of probability.


2019 ◽  
Vol 65 (4) ◽  
pp. 452-459
Author(s):  
Kendhl W Seabright ◽  
Scott W Myers ◽  
Stephen W Fraedrich ◽  
Albert E Mayfield ◽  
Melissa L Warden ◽  
...  

Abstract Phytosanitary treatments for logs and barked wood products are needed to mitigate the spread of thousand cankers disease through the movement of these commodities. The disease threatens eastern black walnut (Juglans nigra L.) populations in the United States. It is caused by repeated attacks by the walnut twig beetle (Pityophthorus juglandis Blackman) and subsequent canker development caused by the fungal pathogen Geosmithia morbida M. Kolařík et al. Methyl bromide (MB) fumigations were evaluated for efficacy against P. juglandis and G. morbida in J. nigra bolts. Fumigation with 82 mg/L MB for 24 h at 4.5° C eliminated P. juglandis in J. nigra, but was ineffective against G. morbida. Subsequent experiments focused on eliminating G. morbida, but results were inconclusive because of low rates of pathogen recovery from naturally infested control bolts. Final experiments used J. nigra bolts artificially inoculated with G. morbida. Fumigations with 240 and 320 mg/L MB for 72 h at 10° C were effective in eliminating G. morbida from J. nigra bolts. Results confirm that the USDA fumigation treatment schedule for logs with the oak wilt pathogen will also mitigate the risk of spreading the thousand cankers disease vector and pathogen by movement of walnut bolts and wood products.


2019 ◽  
Vol 20 (3) ◽  
pp. 133-139 ◽  
Author(s):  
Melanie Moore ◽  
Jennifer Juzwik ◽  
Fredric Miller ◽  
Leah Roberts ◽  
Matthew D. Ginzel

Thousand cankers disease is caused by the coalescence of numerous Geosmithia morbida cankers on branches and stems of Juglans species, leading to branch dieback and eventual tree death. The fungus sporulates in galleries of the walnut twig beetle (Pityophthorus juglandis), allowing for acquisition of pathogen propagules and its subsequent transmission to other branches or trees following adult emergence. Recently, G. morbida has been isolated from Xylosandrus crassiusculus and Xyleborinus saxesenii collected in Ohio and Stenomimus pallidus collected in Indiana. These beetles are known to colonize diseased Juglans nigra in these states. In this study, an operational trap survey for ambrosia beetles, bark beetles, and other weevils was conducted in four eastern states, and captured beetles were assayed to detect G. morbida using both culture and PCR-based methods. A new primer pair (GmF3/GmR13), based on the β-tubulin region, was designed for G. morbida DNA detection. The pathogen was detected on 18 insect species using molecular methods, and live cultures were isolated from two species. This is the first report of the pathogen in Illinois and Minnesota.


2017 ◽  
Vol 46 (3) ◽  
pp. 633-641 ◽  
Author(s):  
Aubree M. Kees ◽  
Andrea R. Hefty ◽  
Robert C. Venette ◽  
Steven J. Seybold ◽  
Brian H. Aukema

2017 ◽  
Vol 17 (3) ◽  
Author(s):  
Jackson Audley ◽  
William E. Klingeman ◽  
Albert Mayfield ◽  
Scott Myers ◽  
Adam Taylor

Forests ◽  
2014 ◽  
Vol 5 (6) ◽  
pp. 1185-1193 ◽  
Author(s):  
Gregory Wiggins ◽  
Jerome Grant ◽  
Paris Lambdin ◽  
Paul Merten ◽  
Katheryne Nix ◽  
...  

2016 ◽  
Author(s):  
Taruna Aggarwal ◽  
Anthony Westbrook ◽  
Kirk Broders ◽  
Keith Woeste ◽  
Matthew D MacManes

Geosmithia morbida is a filamentous ascomycete that causes Thousand Cankers Disease in the eastern black walnut tree. This pathogen is commonly found in the western U.S.; however, recently the disease was also detected in several eastern states where the black walnut lumber industry is concentrated. G. morbida is one of two known phytopathogens within the genus Geosmithia, and it is vectored into the host tree via the walnut twig beetle. We present the first de novo draft genome of G. morbida. It is 26.5 Mbp in length and contains less than 1% repetitive elements. The genome possesses an estimated 6,273 genes, 277 of which are predicted to encode proteins with unknown functions. Approximately 31.5% of the proteins in G. morbida are homologous to proteins involved in pathogenicity, and 5.6% of the proteins contain signal peptides that indicate these proteins are secreted. Several studies have investigated the evolution of pathogenicity in pathogens of agricultural crops; forest fungal pathogens are often neglected because research efforts are focused on food crops. G. morbida is one of the few tree phytopathogens to be sequenced, assembled and annotated. The first draft genome of G. morbida serves as a valuable tool for comprehending the underlying molecular and evolutionary mechanisms behind pathogenesis within the Geosmithia genus. Keywords: de novo genome assembly, pathogenesis, forest pathogen, black walnut, walnut twig beetle.


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