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991.
Gilberto Santos Andrade Dirceu Pratissoli Leandro Pin Dalvi Nicolas Desneux Hugo José Gonçalves dos Santos Junior 《Journal of pest science》2011,84(3):313-320
Trichogramma spp. are major parasitoids of lepidopteran pest eggs, but there is large variation in efficacy toward a given pest among
the numerous described Trichogramma species. It is important to select the Trichogramma species that most effectively parasitize and develop in target pest eggs for biological control. In this context, Trichogramma pretiosum, T. exiguum, T. atopovirilia and T. acacioi were studied in Heliothis virescens eggs under different thermal conditions. The parasitoids were reared at constant temperatures of 20, 25 and 30°C and tested
at these respective temperatures, while parasitoids reared at 25°C were also tested at 20 and 30°C, for a total of 20 species–temperature
combinations. About 30 H. virescens eggs were offered to the parasitoids for 24 h. Among the four species, parasitism rate by T. atopovirilia was highest at all temperature conditions, whereas T. acacioi had the lowest rates of parasitism at 25°C and 25/30°C. Parasitism ranged from 13.8 to 43.8% among all species–temperature
combinations. Viability (emerged parasitoids) ranged from 80.8 to 98.4%, and was deemed satisfactory. The emergence rates
of T. exiguum and T. acacioi were affected by temperature. Temperature also affected the sex ratio of T. exiguum at 25/30°C, whereas T. pretiosum and T. acacioi produced females predominantly independent of temperature. Overall, the parasitoid T. atopovirilia was the most efficient in parasitizing H. virescens eggs, though the levels of parasitism obtained might not ensure its successful use in biological control programs. The temperature-related
differences in biological traits observed in the four Trichogramma species tested hint at the importance of making careful choices regarding climatic conditions where the parasitoid is going
to be used when selecting a species for biological control programs. 相似文献
992.
Christos G. Athanassiou Frank H. Arthur Nickolas G. Kavallieratos James E. Throne 《Journal of pest science》2011,84(1):61-67
Efficacy of the insecticides spinosad and methoprene, applied alone or in combination to wheat, was evaluated against six
stored-product insect species, Rhyzopertha dominica, Sitophilus oryzae, S. granarius, Cryptolestes ferrugineus, Oryzaephilus surinamensis, and Liposcelis bostrychophila. The concentrations of the insecticides were 0.1 and 0.5 ppm for spinosad and 1 and 5 ppm for methoprene. Parental mortality
of R. dominica was 100% on wheat treated with either rate of spinosad, with no progeny production in any combination treatment. Parental
mortality of S. oryzae did not exceed 62%, and progeny production was not reduced by any insecticide treatment. All S. granarius adults exposed on wheat treated with spinosad alone at 0.5 ppm were killed, but parental mortality was reduced when methoprene
was added. Progeny production was reduced in treatments containing spinosad. Mortality of adult C. ferrugineus was 97% or greater in treatments containing spinosad, but adult mortality of O. surinamensis and L. bostrychophila was not reduced by insecticide treatments. The specific combinations of spinosad and methoprene evaluated in our study would
have no benefit over spinosad used alone for control of any of the six species tested. 相似文献
993.
Frauke Kleemann Maximilian von Fragstein Barbara Vornam Annika Müller Christoph Leuschner Andrea Holzschuh Teja Tscharntke Reiner Finkeldey Andrea Polle 《European Journal of Forest Research》2011,130(5):707-716
Knowledge on phenological, morphometric, and phytochemical variation of local progenies of European aspen (Populus tremula, L.) is limited. The goal of this study was to characterize variation in growth and ecologically important leaf properties
in aspen full-sib families in relation to interacting organisms (mycorrhiza, endophytes, and insects) and to determine whether
these interactions were affected by soil application of a systemic fungicide. In local progenies, within-family variation
of neutral molecular genetic markers (nuclear microsatellites) was higher than between families. Significant variation in
growth, production of phenolic defensive compounds and other phytochemical leaf traits was found between families. Phenolic
compounds showed clear negative correlation with generalist herbivores, but did not result in negative trade-off with biomass
production. Differences in mycorrhizal colonization were not found among full-sib families and application of a systemic fungicide
suppressed neither mycorrhizal colonization nor infestation with insects. However, a strong suppression of endophytes occurred,
whose long-term consequences may require attention when fungicides are used in agroforestry plantations. 相似文献
994.
Natalia Kirichenko Julie Flament Yuri Baranchikov Jean-Claude Grégoire 《European Journal of Forest Research》2011,130(6):1067-1074
The Siberian moth, Dendrolimus sibiricus, Tschtv. is the most harmful defoliator of coniferous forests in North Asia. The pest has already spread over the Urals and
continues moving westwards. Recently, it has been recommended for quarantine in member countries by European and Mediterranean
Plant Protection Organization (EPPO). The performances of the pest on coniferous species planted in Europe were assessed on
a range of potted trees corresponding to the spectrum of economically important conifers in the EU: European larch Larix decidua, Norway spruce Picea abies, Scots pine Pinus sylvestris, European black pine Pinus nigra, and the North American species: Douglas fir Pseudotsuga menziesii and grand fir Abies grandis. Larvae showed a potential to survive and complete the development on all these host tree species. Favorable hosts were grand
fir, European larch, and Douglas fir that allowed higher survival, better larval development, and as a result, yielded heavier
pupae and adult moths with higher longevity. Black pine was a poor host but, however, could still support larval and pupal
development. Norway spruce and Scots pine had an intermediate behavior. If accidentally introduced to Europe, the Siberian
moth may become especially damaging in forest stands predominated by European larch and by the North American firs. Norway
spruce and especially the two-needle pines will be less prone to intensive defoliation by this species. The fact that the
pest may damage the range of economically important coniferous species should be taken into account in the pest risk assessment
for Europe and also for North America where the Siberian moth occurrence is considered likely. 相似文献
995.
Matts Lindbladh Adam Felton Renats Trubins Ola Sallnäs 《European Journal of Forest Research》2011,130(5):861-869
As resources allocated specifically for conservation are limited, there is a need to ensure conservation policy initiatives
lead to effective conservation outcomes. In this study, we investigated the potential conservation benefits from alternative
spatial allocations of old deciduous stands to a landscape dominated by coniferous production forests owned primarily by non-industrial
private forest owners. As a target species, we used the long-tailed tit (Aegithalos caudatus), a species associated with deciduous forests and known to be sensitive to isolation. We used a previously published model
based on empirical data on the occurrence of this species, to assess the probability of occurrence of the bird in a 4,000 km2 area in southern Sweden for which we possess detailed spatial GIS data (kNN data) of tree species composition and age. We
assessed alternative scenarios where old deciduous forest was allocated with or without respect to distance from existing
old deciduous forests. Due to the long-tailed tit’s habitat requirement increasing the amount of old deciduous forests close
to existing habitats was the most effective strategy. However, the potential advantages of this strategy may in fact be overturned
in favor of the other scenarios if ownership structures and probable uptake rates of policy initiatives are also considered.
If a policy initiative is targeted toward owners with properties in close proximity to existing suitable habitat, when compared
to if all forest owners are targeted, a higher proportion of owners is needed to participate in order to achieve the same
degree of habitat creation for the species. Here, we discuss the potential benefits for effective conservation policy formulation
from integrating spatially explicit datasets and detailed ecological knowledge with land-ownership structures and policy uptake
scenarios. 相似文献
996.
Lara Vilar del Hoyo M. Pilar Martín Isabel F. Javier Martínez Vega 《European Journal of Forest Research》2011,130(6):983-996
About 90% of the wildland fires occurred in Southern Europe are caused by human activities. In spite of these figures, the
human factor hardly ever appears in the definition of operational fire risk systems due to the difficulty of characterising
it. This paper describes two spatially explicit models that predict the probability of fire occurrence due to human causes
for their integration into a comprehensive fire risk–mapping methodology. A logistic regression technique at 1 × 1 km grid
resolution has been used to obtain these models in the region of Madrid, a highly populated area in the centre of Spain. Socio-economic
data were used as predictive variables to spatially represent anthropogenic factors related to fire risk. Historical fire
occurrence from 2000 to 2005 was used as the response variable. In order to analyse the effects of the spatial accuracy of
the response variable on the model performance (significant variables and classification accuracy), two different models were
defined. In the first model, fire ignition points (x, y coordinates) were used as response variable. This model was compared with another one (Kernel model) where the response variable
was the density of ignition points and was obtained through a kernel density interpolation technique from fire ignition points
randomly located within a 10 × 10 km grid, which is the standard spatial reference unit established by the Spanish Ministry
of Environment, Rural and Marine Affairs to report fire location in the national official statistics. Validation of both models
was accomplished using an independent set of fire ignition points (years 2006–2007). For the validation, we used the area
under the curve (AUC) obtained by a receiver-operating system. The first model performs slightly better with a value of AUC
of 0.70 as opposed to 0.67 for the Kernel model. Wildland–urban interface was selected by both models with high relative importance. 相似文献
997.
Raffaele Spinelli Natascia Magagnotti Carla Nati 《European Journal of Forest Research》2011,130(5):737-744
In Italy, poplar plantations represent an important source of wood products, and especially of high-quality veneer logs. These
plantations offer favourable conditions to the introduction of forest mechanisation, and especially easy access and industrial
management. However, owners fear that mechanised log-making may cause value losses, due to poor length measurement, log surface
damage and improper grading. This study compared the performance of manual and mechanised log-making on ten commercial operations,
in order to determine the occurrence and the severity of possible value losses due to product degrade. The study found that
length measurement errors are smaller for mechanised processing, while the frequency and severity of log surface damage are
the same for both treatments. In three cases out of five, mechanised log-making extracted the same value from the stems as
manual log-making: in the remaining two, differences were very small and went opposite directions. Significant differences
were found between operators, stressing the importance of operator skills and motivation. In fact, the log-making specifications
and the pricing structure applied to poplar processing are relatively simple and are unlikely to challenge the ability of
personnel and equipment. At present, most Italian poplar growers are unaware of the potential offered by modern technology,
whose intelligent use would boost value recovery and decrease harvesting cost. Significant benefits may derive from the introduction
of optimised bucking, which may help shifting to a more articulated and rewarding product strategy. 相似文献
998.
Stefano Casalegno Giuseppe Amatulli Annemarie Bastrup-Birk Tracy Houston Durrant Anssi Pekkarinen 《European Journal of Forest Research》2011,130(6):971-981
Proactive forest conservation planning requires spatially accurate information about the potential distribution of tree species.
The most cost-efficient way to obtain this information is habitat suitability modelling i.e. predicting the potential distribution
of biota as a function of environmental factors. Here, we used the bootstrap-aggregating machine-learning ensemble classifier
Random Forest (RF) to derive a 1-km resolution European forest formation suitability map. The statistical model use as inputs
more than 6,000 field data forest inventory plots and a large set of environmental variables. The field data plots were classified
into different forest formations using the forest category classification scheme of the European Environmental Agency. The
ten most dominant forest categories excluding plantations were chosen for the analysis. Model results have an overall accuracy
of 76%. Between categories scores were unbalanced and Mesophitic deciduous forests were found to be the least correctly classified
forest category. The model’s variable ranking scores are used to discuss relationship between forest category/environmental
factors and to gain insight into the model’s limits and strengths for map applicability. The European forest suitability map
is now available for further applications in forest conservation and climate change issues. 相似文献
999.
The spruce bark beetle, Ips typographus, is one of the most extensively studied European forest pests. Gaps exist in the knowledge about second generation breeding
performance in bivoltine populations. In this study, the breeding performance of the second generation was evaluated in three
bivoltine populations of I. typographus in the SE Alps. Length of the maternal galleries (from 40.5 to 44.8 mm), population growth rate (PGR; from 0.7 to 3.6), and
emerged adults per m2 (from 669 to 1,570 insects/m2) varied among populations and were negatively correlated with bark colonisation density. Pheromone traps set up in the three
investigated forests differed in the number of trapped beetles, with mean captures ranging between 5,310 and 19,850 insects
per trap. The populations giving the highest captures in the traps showed the lowest bark colonisation density (248 vs. 489
maternal galleries per m2) and the best breeding performance. The populations of parasitoids and predators corresponded to just 1–9 and 2–10% of the
emerging I. typographus adults, respectively, and phloem temperature never reached thresholds lethal to I. typographus. Interspecific competition was negligible, whereas intraspecific competition was found to be the main factor affecting the
breeding performance of the second generation, although with different intensity according to the colonisation density. It
is hypothesised that competition with the first generation and spring precipitation influence the number of suitable hosts
available to the second generation. 相似文献
1000.
Pavel Šamonil Martin Valtera Stanislav Bek Barbora Šebková Tomáš Vrška Jakub Houška 《European Journal of Forest Research》2011,130(6):1075-1091
Soil variability was assessed in a 74.2-ha area within the Žofínsky prales natural forest. Parameters evaluated for 1765 soil
profiles inside 353 graticule plots were as follows: (1) thickness of organic horizons, (2) thickness and form of mineral
horizons, (3) humus form (HF), (4) soil taxonomic unit (STU) and (5) anomalies. In addition, soil reaction (pHKCl) and oxidizable carbon content (Cox) were measured in the laboratory for 734 samples from the upper mineral (A) and lower mineral (B) horizons. The most frequently
occurring humus form was mor followed by moder, hydromor and peaty T-horizon. Entic Podzols, Dystric Cambisols, Haplic Cambisols,
Albic Podzols, Histic (or Haplic) Gleysols, Endogleyic Stagnosols, Fibric or Hemic or Sapric Histosols and Stagnic Gleysols
were all present at the site despite its homogeneous geological bedrock. Overall coefficient of variance (CV) was lower in
terrestrial soils compared with (semi-)hydromorphic soils. Overall variance decreased in both soil groups with increasing
depth, as did CV differences between the fine (up to 10 m) and the locality scales. The lowest CV values occurred for Cox and pHKCl. The CV values differed between STUs as well. Compared to lower horizons, variograms of upper horizons showed greater autocorrelation
at the intermediate spatial scale (10–320 m)—ranging from 50 to 150 m. Semivariance values, however, reached 70–80% of sill
already at a distance of 10 m. The most significant factor of variability at all studied spatial scales is presumably the
soil disturbance regime, followed by terrain micro-topography and the effect of tree species. 相似文献