28 research outputs found

    Phytophthora ssp. som skadegörare på vedartat material i svenska park- och naturområden

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    Ett ökande problem inom Europa och Sverige är invasiva skadegörare på vedartad material av släktet Phytophthora. Dessa introducerade patogener har samevolverat med värdväxter i sin ursprungliga miljö. När dessa skadegörare sprids i andra ekosystem kan de orsaka ett epidemiskt sjukdomsförlopp på flertalet olika växter i sin nya miljö. Phytophthora alni subsp. uniformis är en typisk sådan skadegörare, vars geografiska ursprung är oklart men troligtvis är den en hybrid mellan två arter av Phytophthora som med hjälp av plantskolehandeln möts. Denna patogen har orsakat stor skada på vattennära alar i södra Sverige, och får idag anses vara etablerad. Den bristfälliga information som finns i Sverige pekar på det finns ett antal olika Phytophthora-arter som orsakar stora skador på våra ekosystem. I detta arbete ges en generell introduktion till släktet Phytophthora, dess unika egenskaper som skadegörare samt vilka olika arter som förekommer i Sverige. Vidare behandlas problematiken kring hur karantänskadegörare skall hanteras och när man bör rapportera till Jordbruksverket. I diskussionsdelen görs en ansats till att utröna hur insatser kan/bör utformas och implementeras i park- och naturverksamhet. Viktigt är att inse att detta inte är en skadegörare man enkelt kan bekämpa och bli av med. Istället bör man sikt etablera sådana insatser att introducerings- och spridningsrisk samt genomslagskraft av Phytophthora-arter förblir så små som möjligt för park- och naturområdens ekosystem.An increasing problem in Europe and Sweden (damaging woody material) is invasive pathogens of the genus Phytophthora. These introduced pathogens have co-evolved with host plants in their original environment. This means that when these pathogens are spread in other ecosystems they can cause damage on an epidemic scale in their new environment. A characteristic such pathogen is Phytophthora alni subsp. uniformis, which has an unknown geographic background but probably is a hybrid between two Phytophthora species that has met through the trade within plant nurseries. This pathogen should be considered to be established in Sweden and is causing extensive damage on riparian Alders in the southern parts. A general introduction to the genus Phytophthora, its unique traits as pathogen and the species known to exist in Sweden is given within this thesis. This thesis also considers the problematic aspects of how quarantine pathogens within this genus are treated and when to report to the Swedish Agricultural Board. In the discussion efforts that can be implemented in parks and natural environment are suggested. It is important to realize that pathogens like Phytophthora are hard to eradicate. The aims should be to on a long term basis implement such efforts that introduction, spread and impact of Phytophthora is minimized in ecosystems of parks and natural environments

    Assessing allelochemicals as species-specific attractants for the cherry bark tortrix, Enarmonia formosana (Lepidoptera: Tortricidae)

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    Field trapping experiments were carried out in Norway to measure attraction of the cherry bark tortrix (CBT) Enarmonia formosana to volatile blends of candidate compounds including acetic acid (AA), linalool oxide pyranoid (LOXP), 2-phenylethanol (PET), pear ester (E,Z)2,4-ethyl decadienoate (PE) and (E)-beta-farnesene (BF). The binary blend of AA and LOXP caught the highest number of CBT adults. While addition of PET along with PE did not significantly change the attraction, a sex-dependent decrease of female captures was found when LOXP was replaced by PET/PE. Male attraction to AA/LOXP did not differ when PET/PE were added to the blend or when LOXP was substituted by the same two compounds. A similar attraction to blank traps was recorded for the ternary blend of LOXP/PET/PE, for the binary blend of PET/PE and for LOXP alone, supporting AA as a possible fundamental component of CBT kaimmone. In addition, a lower number of bycatches of Hedya nubiferana, Anthophila fabriciana, Synanthedon myopaeformis, Pammene spp. and Pandemis spp. were scored in the AA/LOXP than in any blend including AA/PET/PE. BF was not behaviourally active on CBT in our field experiments. The high attraction of both sexes of CBT to the binary blend of AA/LOXP represents a first step towards the identification of a multicomponent kairomone for this pest. A continuous flight activity of both sexes of CBT was recorded from the end of May until the beginning of August, supporting the hypothesis that CBT is univoltine in Norway. Because larval infestation on tree trunks varies substantially with apple varieties, we encourage the collection of additional data to attempt a correlation between adult catch by AA/LOXP traps and the following larval population

    Diverging olfactory sensitivities to yeast volatiles reflect resource partitioning of tephritids and drosophilids

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    As pests of fruits and vegetables, ovipositing tephritid fruit flies are infamous for their frugivory. Yet, adult tephritids have remained saprophytic in their feeding behavior, as they require decomposing, protein rich media for sexual maturation and oogenesis. Drosophilid fruit flies, in contrast, are saprophytic both during oviposition and feeding. Here we compared the sensory and behavioral responses of two tephritid (Bactrocera dorsalis and Ceratitis capitata) and two drosophilid species (Drosophila melanogaster and Drosophila suzukii) to differentially aged cultures of the yeast Saccharomyces cerevisiae. We assessed convergence and divergence in the detection of and behavioral response to these attractive substrates, and how these might be linked to the roles of the substrates for the different taxa. The headspace shifted substantially as broth cultures transitioned from active (1-day) to inactive (8- and 15-days). Interestingly, Drosophila flies were significantly attracted to actively fermenting 1-day old yeast cultures, whereas the preference shifted to older cultures for the tephritids. Bactrocera dorsalis flies preferred inactive, lysing cultures (8- and 15-days old). We identified compounds from the 1- to 8-days old broth cultures that elicited antennal responses in each species. Synthetic blends composed of antennally active compounds evoked similar behavioral responses as broth cultures. Similarly, the attractiveness of less attractive broth cultures (1- and 8-days old for drosophilids and tephritids, respectively) could be augmented by adding volatiles of the more attractive cultures. The results show that the volatile profiles of fermenting substrates evolve quantitatively and qualitatively, and that fly species key into volatile blends that indicate suitability of the substrates for their purposes. For drosophilids early arrival at fermenting substrates confers a competitive advantage to offspring. In contrast, for tephritid the concentration and availability of protein is facilitated by older, lysed yeast cultures. The data from this comparative study are also instrumental in the development of novel lures for these pests

    Predator odor can reduce acorn removal by granivorous rodents in mixed oak forest stands

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    Developing better practices for rodent pest control is of high importance to reduce damage during forest restoration and in crop production. For example, during direct seeding with large and highly attractive seeds such as acorns, most seeds will disappear due to consumption or dispersal if not protected. An unexplored concept in reducing rodent damage is the use of repellents derived from predators. We tested the efficiency of three volatile compounds (2-propylthietane, 2-phenylethylamine and indole) associated with predators as rodent repellent candidates and scored the reduction of acorn (Quercus petraea) removal at two field sites in southern Sweden. We further investigated at what distance (5 cm, 10 cm, and 15 cm) from the odor source the odors were efficient in lowering the removal of acorns. Removal was lowest with 2-propylthietane (25-45 % of acorn removal), followed by 2-phenylethylamine (75-95% acorn removal) at 5 cm. Indole failed to decrease acorn removal and did not differ significantly from the control treatments. In the control treatments, almost all acorns (95-100%) were removed from the plots during the 48-hour sessions at both sites, and the acorns were removed faster than in the other treatments. Removal increased with distance from the 2-propylthietane odor dispenser at both field sites. Here, the lowest acorn removal occurred at 5 cm from the odor disperser. Our short time experiment shows for the first time the potential of using 2-propylthietane for short-term protection of acorns from foraging by granivorous rodents in oak woodlands. To help increase the reliability of direct seeding as a method for regenerating and restoring forests, future studies should investigate whether the range and longevity in the field of predator odor formulations can be improved

    The potential of biological control against Heterobasidion root rot is not realized in practical forestry

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    For about 25 years, forest managers in Sweden have been treating stumps following harvesting with Phlebiopsis gigantea, retailed as Rotstop (R) S gel, against spore infections of Heterobasidion, which cause root rot in order to minimize losses in timber production. However, not all forest managers trust the efficacy of stump treatment and this fact has hindered widespread adoption of stump treatment using P. gigantea. In this study, we evaluated stump treatment in the field during commercial thinning operations across 15 sites, by assessing the degree of stump coverage and subsequent infection levels in stump discs. In total, 45 % of all stumps were infected with Heterobasidion spp.. Nineteen percent of all stumps were considered to have full (100 %) coverage by Rotstop (R) S but contractors failed to achieve the manufacturers stipulated minimum coverage (85 %) in approximately 1/3 of all stumps. Using PCR, we could only detect the presence of P. gigantea in 73 % of the tested stumps. Large variation occurred between stump coverage and the recovery of P. gigantea in wood chip samples collected from stump discs across sites. In the worst case, we detected P. gigantea in only three out of ten treated stumps at one site. Despite this discrepancy we saw a clear reduction of the size of Heterobasidion infections on stumps where stump treatment coverage was more than 85 % of the stump surface.Our results suggest that forest operators in Sweden repeatedly fail to either apply a spore solution of P. gigantea or cover enough of the stumps to provide the desired protection. The outcome of such sub-standard application, could further undermine the usage of biological control agents in forestry and limit any potential control against Heterobasidion spp.

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Data in, lures out: designing selective lures against fruit pests

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    With the push for rebuilding ecosystem resilience and the aim to lower the footprint of agriculture, there is an urgent need for novel, sustainable tools for managing pests. Insect olfaction is a good target to designing such novel tools. However, the rate at which odor-based insect control innovations are churned out is underwhelming. This thesis aims to accelerate the identification of lures using pests of wine and tropical fruits as models. Volatiles from microorganisms, hosts or other ecological relevant substrates, can be used to construct attractive lures. Such a lure was designed for Lobesia botrana, a severe pest in wine. First, volatiles emitted by microbe inoculated grapes were identified using GC-MS. A limited set of shared volatiles was attractive in the field, and further tailored to find a balance between attractiveness and selectivity. The best lure for L. botrana also caught more of other species such as important natural enemies, impacting ecosystem services provided in the vineyard. Hence the most attractive lure is not always the best. A group of invasive pests in the true fruit fly family, Tephritidae, was used as model organisms to design a novel workflow from primary research to lure design. Ranges of olfactory responses, olfactomes, of fruit flies that differ in ecology and phylogeny served as input to a database. Custom tools were developed that allowed for mining this database for ecological as well as evolutionary signals. In the selected pests, ecology overrode phylogeny in the electrophysiological response profile across both olfactory organs, antennae and palps, as well as different substrates. Further, a set of compounds was found that formed a preadaptive bridge between fruits, and a subset links the flies ancestral saprophily to their derived frugivory. Candidate lures, more attractive than fruits, were also tested in a novel six-choice olfactometer. The work shows that selective lures can be designed from generic volatiles and that this process can be strongly accelerated through comparative olfactomics
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