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Villamuriel de Cerrato, Spain

Castrillo L.A.,Cornell University | Hajek A.E.,Cornell University | Pajares J.A.,University of Valladolid | Thomsen I.M.,Copenhagen University | And 5 more authors.
Fungal Biology | Year: 2015

Sirex noctilio is a woodwasp of Eurasian origin that was inadvertently introduced to the southern hemisphere in the 1900s and to North America over a decade ago. Its larvae bore in Pinus spp. and can cause significant mortality in pine plantations. S noctilio is associated with a symbiotic white rot fungus, Amylostereum areolatum, which females inject into trees when they oviposit and which is required for survival of developing larvae. We compared the genetic diversity of A. areolatum isolated from S. noctilio and other woodwasps collected from Europe and from northeastern North America to determine the origin of introduction(s) into the United States. Multilocus genotyping of nuclear ribosomal regions and protein coding genes revealed two widespread multilocus genotypes (MLGs) among the European samples, one of which is present in the US. The other two MLGs associated with S. noctilio in the US represented unique haplotypes. These latter two haplotypes were likely from unrepresented source populations, and together with the introduced widespread haplotype reveal multiple A. areolatum MLGs introduced by S. noctilio and indicate possible multiple S. noctilio introductions to North America from Europe. Our results also showed a lack of fidelity between woodwasp hosts and Amylostereum species. © 2015 The British Mycological Society. Source


Castrillo L.A.,Cornell University | Hajek A.E.,Cornell University | Pajares J.A.,University of Valladolid | Thomsen I.M.,Copenhagen University | And 6 more authors.
Fungal Biology | Year: 2015

Sirex noctilio is a woodwasp of Eurasian origin that was inadvertently introduced to the southern hemisphere in the 1900s and to North America over a decade ago. Its larvae bore in Pinus spp. and can cause significant mortality in pine plantations. S noctilio is associated with a symbiotic white rot fungus, Amylostereum areolatum, which females inject into trees when they oviposit and which is required for survival of developing larvae. We compared the genetic diversity of A. areolatum isolated from S. noctilio and other woodwasps collected from Europe and from northeastern North America to determine the origin of introduction(s) into the United States. Multilocus genotyping of nuclear ribosomal regions and protein coding genes revealed two widespread multilocus genotypes (MLGs) among the European samples, one of which is present in the US. The other two MLGs associated with S. noctilio in the US represented unique haplotypes. These latter two haplotypes were likely from unrepresented source populations, and together with the introduced widespread haplotype reveal multiple A. areolatum MLGs introduced by S. noctilio and indicate possible multiple S. noctilio introductions to North America from Europe. Our results also showed a lack of fidelity between woodwasp hosts and Amylostereum species. © 2015 The British Mycological Society. Source


Martinez-Alvarez P.,University of Valladolid | Fernandez-Gonzalez R.A.,University of Valladolid | Sanz-Ros A.V.,University of Valladolid | Sanz-Ros A.V.,Calabazanos Forest Health Center | And 2 more authors.
Biological Control | Year: 2016

Pitch canker disease, which affects pines and is caused by the fungus Fusarium circinatum, cannot be effectively controlled at present. Current restrictions on the use of chemicals and fungicides in forests are driving research into alternative methods of reducing the damage caused by the pathogen. Biological control with fungal endophytes is a promising and environmentally friendly strategy. In this study, 154 endophyte isolates were selected from a collection of 546 fungi tested in a preliminary confrontation assay. These isolates were then tested against F.circinatum in an in vitro antagonism experiment. Four different types of indicators (length of the central axis of the colony of the pathogen, the shape coefficient, percentage inhibition of radial growth and percentage inhibition zone) were used to detect and quantify the antagonistic activity directed towards the pathogen by the endophytes. The six isolates that showed the most promising results were inoculated in the field, together with the pathogen, into seedlings of Pinus radiata, P.sylvestris, P.pinaster, P.nigra and P.pinea, to test whether they could reduce the damage caused by F.circinatum. In total, 138 endophytes displayed antagonistic activity towards F.circinatum in the dual cultures of the in vitro experiment. In the field test, the endophytes Chaetomium aureum and Alternaria sp. reduced the area under disease progress curve (AUDPC) for the P.radiata seedlings, indicating that they may therefore be suitable for use as biological control agents (BCAs) of the disease. © 2015 Elsevier Inc.. Source


Etxebeste I.,University of Valladolid | Alvarez G.,University of Valladolid | Perez G.,Calabazanos Forest Health Center | Pajares J.A.,University of Valladolid
Journal of Applied Entomology | Year: 2012

The identification and description of the chemical signals involved in the aggregation of bark beetles may lead to the development of integrated pest management strategies using synthetic pheromones. Ips sexdentatus Boern. (Col.: Scolytinae) colonizes trees of the Pinus genus across Europe, causing severe damage in occasions. The effect of cis-verbenol, ipsenol, 2-methyl-3-buten-2-ol (MB) and myrtenol in relation to the major pheromonal compound ipsdienol on the aggregation behaviour of I. sexdentatus was studied on four field bioassays. The ternary blend of racemic ipsdienol, cis-verbenol and racemic ipsenol consistently caught the highest number of bark beetles, resulting in large standardized mean differences (d unbiased>0.8). The binary blends between ipsdienol and ipsenol, and ipsdienol and cis-verbenol also improved the performance of ipsdienol, although only ipsenol did it significantly. On the other hand, catches were reduced (d unbiased=-0.96) when MB was released along ipsdienol, although the effect was found to be non-significant. On a third bioassay, the relative release rates between ipsdienol, ipsenol and cis-verbenol were studied. Although no differences were found between the ternary blends, a ratio of 1:0.25:0.5 for ipsdienol, ipsenol and cis-verbenol, respectively, scored the strongest effect size (d unbiased=1.17). A fourth bioassay studied the behavioural effects of myrtenol and found no significant modifications to previously established findings. Myrtenol on its own attracted almost no individuals of I. sexdentatus. High numbers of bark beetle predators Thanasimus formicarius L. and Temnochila caerulea Olivier were trapped during the trials. The binary blend between ipsdienol and ipsdienol was shown to catch the highest significant amount of T. formicarius, whereas numbers of T. caerulea caught were highest on the binary blend between cis-verbenol and ipsdienol. Presented results establish the ternary blend between ipsdienol, ipsenol and cis-verbenol as a reference functional aggregative lure ready to be used on the management of I. sexdentatus. © 2011 Blackwell Verlag, GmbH. Source


Martin A.,Calabazanos Forest Health Center | Etxebeste I.,University of Valladolid | Perez G.,Calabazanos Forest Health Center | Alvarez G.,University of Valladolid | And 2 more authors.
Agricultural and Forest Entomology | Year: 2013

1 Thanasimus formicarius and Temnochila caerulea, two of the main predators of Ips sexdentatus, a well-known forest pest in Southern Europe, are captured in high numbers when trapping I. sexdentatus as a result of the kairomonal effect of the lures used. 2 A preliminary field trial showed that predators could survive for at least 1 week within trapping containers, although predator mutilation and high predator death rates were observed. 3 Different modifications of conventional multiple funnel and slot traps with the objective of reducing natural enemy entrance into trap containers were bioassayed in field experiments conducted over four seasons. Based on the larger sizes of predators, different designs using welded wire-mesh screens improved performance to different extents. Providing escape windows just above the screen on multiple funnel traps gave the most promising results, including when effect sizes among all tested designs were compared. 4 Thus, a simple modification of the lowest funnel of the multiple funnel traps would reduce the bycatch of T. formicarius and T. caerulea, hence improving the efficiency of trapping programmes by lowering the likely impact on natural populations of these predators. © 2012 The Royal Entomological Society. Source

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