Suchergebnisse

Ambrosia bark beetles belong to a group of xylomycetophagous insects from the order Coleoptera, family Curculionidae and are characterized as important pests of oak timber. Galleries they form during their life cycle and infect with »ambrosia fungi« significantly decrease the economic value of oak roundwood. A state owned Croatian company »Hrvatske šume« Ltd. manages FSC certificated forests, where pedunculate and sessile oaks account for 22.6% in the annual allowable cut. Methods of oak roundwood protection, that used to be implemented in the past, are now banned in accordance with EU legislation as well as FSC criteria of forest protection. In these forest management conditions, it becomes necessary to introduce new biotechnical methods for oak roundwood protection. Available commercial products, flight barrier traps and synthetic semiochemicals, as well as pretreated insecticide treated polymer nets, were tested as means of integrated oak roundwood protection. Implementation of these products was tested in field conditions. Good knowledge of phenology of ambrosia bark beetles, thorough understanding of timber harvesting operations and field conditions that dominate in even aged oak forests, is crucial if applied methods are to be effective and taken on time. Field experiments conducted in this research showed that early seasonal deployment of semiochemically baited flight barrier traps can reduce the number of bark beetles that infest oak timber. It was also concluded that without additional protection with polymer nets, it is not possible to protect oak timber in compliance with strict FprEN 1316-1: 2012 E standards for oak roundwood classes, which do not allow any timber infestation in the highest quality grades (A and B quality class). Semiochemicals used as repellents during the research were ineffective. In the early months of spring, oak roundwood is at high risk of infestation at the roadside landings, where it is waiting to be transported.

European coniferous forests are currently threatened by bark beetles (e.g. Ips typographus) because of an increasing incidence of triggering factors, such as drought and windstorms. Furthermore, such natural disturbances are expected to increase in terms of magnitude and frequency due to climate change, and thus interacting with each other. Here, we present a particular case study in the Southern Italian Alps (Gares, Canale d'Agordo, Belluno), in which wind disturbance interacts with an ongoing outbreak of I. typographus, probably associated with an extended drought in the previous three years. By combining remote sensing and field surveys, we spatially reconstructed the bark beetle attack in the period 2015-2021, which includes the Vaia windstorm in October 2018. Although the windstorm occurred in an expanding phase of the bark beetle outbreak, attacks on standing trees did not occur during the first year after the windstorm but were observed two years later. Our findings suggest that an overlap of a large availability of wind felled trees with an incipient outbreak of I. typographus resulted in an immediate decrease of standing trees mortality in the year following the storm. However, the fallen trees worked as a hidden sink for the beetle population, which in the following years massively attacked the standing trees that survived the storm.

A broad host range and the utilization of living but weakened trees contribute, in part, to the invasion success of ambrosia beetles (Curculionidae: Scolytinae). The present study assessed the capability of freeze stress to induce attacks by ambrosia beetles. Freeze stress predisposed Cercis canadensis L., Cornus florida L., Malus pumila Mill. and Styrax japonicus Sieb. to attack under field conditions, although no attacks occurred on untreated trees. More attacks occurred on freeze-stressed versus flood-stressed M. pumila in Virginia but not for S. japonicus in Ohio. Attacks on flooded trees were skewed towards the base of the trunk, whereas attacks on freeze-stressed trees mainly occurred around the upper regions of the trunk and into the branches. The predominant species recovered were Anisandrus maiche Stark and Xylosandrus germanus (Blandford) in Ohio, and Xylosandrus crassiusculus (Motschulsky) in Virginia. Ethanol emissions from trunks of S. japonicus were detected by solid phase microextraction-gas chromatography-mass spectrometry at 1 day after imposing freeze stress, peaking 4 days after injury. Trees with an intolerance of freeze stress are predicted to be vulnerable to attack, especially when subjected to mild winter temperatures followed by late-spring freezes. Freeze stress could thereby facilitate the destructiveness of exotic ambrosia beetles. ; Floriculture and Nursery Research Initiative (USDA-FNRI); Horticultural Research Institute (HRI); USDA-ARS National Program 304-Crop Protection and Quarantine [3607-22 000-012-00D] ; This research was supported by the Floriculture and Nursery Research Initiative (USDA-FNRI), Horticultural Research Institute (HRI) and USDA-ARS National Program 304-Crop Protection and Quarantine (Project 3607-22 000-012-00D). We thank Jenny Barnett (USDA-ARS), Hannah Knapic (USDA-ARS) and Shelby Reutter (USDA-ARS) for technical assistance. We thank the anonymous reviewers for useful comments. Mention of proprietary products or companies does not imply any endorsement or preferential treatment by the USDA-Agricultural Research Service. ; Public domain authored by a U.S. government employee

The battle about logging in the protected Bialowieza primeval forest in Poland puts the rule of law in the European Union in danger – in more than just one way.

Non-native ambrosia beetles (Coleoptera: Curculionidae), especially Xylosandrus compactus (Eichhoff), Xylosandrus crassiusculus (Motschulsky) and Xylosandrus germanus (Blandford), are destructive wood-boring pests of trees in ornamental nurseries and tree fruit orchards. Previous studies have demonstrated the adults are repelled by verbenone and strongly attracted to ethanol. We tested a "push-pull" semiochemical strategy in Ohio, Virginia and Mississippi using verbenone emitters to "push" beetles away from vulnerable trees and ethanol lures to "pull" them into annihilative traps. Container-grown trees were flood-stressed to induce ambrosia beetle attacks and then deployed in the presence or absence of verbenone emitters and a perimeter of ethanol-baited interception traps to achieve the following treatment combinations: (a) untreated control, (b) verbenone only, (c) ethanol only, and (d) verbenone plus ethanol. Verbenone and ethanol did not interact to reduce attacks on the flooded trees, nor did verbenone alone reduce attacks. The ethanol-baited traps intercepted enough beetles to reduce attacks on trees deployed in Virginia and Mississippi in 2016, but not in 2017, or in Ohio in 2016. Xylosandrus germanus, X. crassiusculus and both Hypothenemus dissimilis Zimmermann and X. crassiusculus were among the predominant species collected in ethanol-baited traps deployed in Ohio, Virginia and Mississippi, respectively. Xylosandrus germanus and X. crassiusculus were also the predominant species dissected from trees deployed in Ohio and Virginia, respectively. While the ethanol-baited traps showed promise for helping to protect trees by intercepting ambrosia beetles, the repellent "push" component (i.e., verbenone) and attractant "pull" component (i.e., ethanol) will need to be further optimized in order to implement a "push-pull" semiochemical strategy. ; USDA Floriculture and Nursery Research Initiative (USDA/FNRI); Horticultural Research Institute (HRI); USDA-ARS National Program 304-Crop Protection and Quarantine [3607-22000-012-00D]; USDA-ARS National Program 305-Crop Production [6062-21430-002-00D]; USDA National Institute of Food and AgricultureUnited States Department of Agriculture (USDA) [SC-1700473] ; Funding for this project was provided by the USDA Floriculture and Nursery Research Initiative (USDA/FNRI); Horticultural Research Institute (HRI); USDA-ARS National Program 304-Crop Protection and Quarantine (Project 3607-22000-012-00D); USDA-ARS National Program 305-Crop Production (Project 6062-21430-002-00D); and USDA National Institute of Food and Agriculture (Project SC-1700473). We thank Jenny Barnett (USDA-ARS), Jenna Zhu (USDA-ARS) and Mary Seward (Hampton Roads AREC) for technical assistance. ; Public domain authored by a U.S. government employee