bluuebunny/crossref_metadata_2025_split huggingface dataset:
Attack density and breeding success of bark beetles (Coleoptera, Scolytidae) at different distances from forest‐clearcut edge
Authors: Peltonen Mikko , Heliövaara Kari 
Published: March 2003

Summary1 Attack density and breeding success of bark beetles (Coleoptera: Scolytidae) and the abundance of their predators were studied at forest‐clearcut edges in southern Finland on Norway spruce, Picea abies, bolts placed at different distances from a forest‐clearcut edge.2 Attack densities of two species, Hylurgops palliatus and H. glabratus, increased markedly towards the forest interior. The breeding success of H. palliatus was increased with increasing distance from the stand edge. None of the recorded 10 bark beetle species was distinctly abundant near the edge, but Pityogenes chalcographus appeared to prefer this zone.3 There were no significant differences in numbers of bark beetle predators between the forest interior and the edge. Forest‐clearcut edge had a significant effect on the desiccation of sample bolts.4 Thus, forest edge is likely to affect the colonization behaviour and breeding success of bark beetles via host material properties.
Variability of Lycopersicon hirsutum f. typicum and possible compounds involved in its resistance to Tuta absoluta
Authors: Ecole C. C. , Picanço M. , Jham G. N. , Guedes R. N. C. 
Published: March 2003

Summary1 The resistance of Lycopersicon hirsutum f. typicum and L. esculentum to the leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) was investigated in two experiments. The first experiment assessed the resistance of L. hirsutum f. typicum (accession LA 1777) to T. absoluta, the second assessed the variability of the resistance among plants of this accession.2 It was found that L. hirsutum f. typicum was resistant to the leafminer, which showed longer larval phase, higher larval mortality, smaller numbers of large mines and greater numbers of small mines/leaf than on L. esculentum. Seven plants of the accession LA 1777 showed lower number of small mines/leaf, but their results of larval mortality and length of larval and pupal phase were similar. Twenty‐two peaks were observed in total ion chromatograms of L. hirsutum f. typicum hexane extracts of leaves subjected to a gas chromatographic‐mass spectrometric analysis (CG‐MS). However, the matches obtained between the peak spectra and the MS database were too low to justify even preliminary identification of the compounds.
Multiple host use by the egg parasitoid Trissolcus basalis (Wollaston) in a soybean agricultural system: biological control and environmental implications
Authors: Loch A. D. , Walter G. H. 
Published: March 2003

Summary1 Species of bugs (Hemiptera: Pentatomidae and other families) that are parasitized by the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) in the soybean agricultural system on the Darling Downs in south‐eastern Queensland, Australia, are reported. The degree to which eggs of each bug species are used by T. basalis is quantified, which allows assessment of the role of these alternative host species in the biological control of the green vegetable bug Nezara viridula (L.).2 Egg masses of nine species of pentatomid bugs and one unidentified bug species were collected. Parasitism rates of egg masses of all species averaged 50–70% but were significantly lower for the more important pest species, including the green vegetable bug, than for some of the agriculturally less important species.3 Trissolcus basalis emerged from nearly all species collected and was the major parasitoid to emerge from most species. A number of native species were parasitized heavily by T. basalis and parasitism of such species may enhance biological control of the green vegetable bug, but may also pose environmental concerns. Parasitism of predatory bugs by T. basalis may have a negative impact on the biological control of other pests, especially lepidopterous pests.4 Although the impact of T. basalis on native and predatory host species was not directly quantified, these host species remain abundant and therefore do not appear to be affected adversely by such high rates of parasitism.
Spatio‐temporal dynamics of willow beetle (Phratora vulgatissima) in short‐rotation coppice willows grown as monocultures or a genetically diverse mixture
Authors: Peacock L. , Herrick S. , Brain P. 
Published: March 2003

Summary1 Phratora vulgatissima (Chrysomelidae) is the major pest of short‐rotation coppice willows in the U.K., capable of causing severe defoliation in monoculture plantations. As this beetle shows feeding preferences between willow clones, knowledge of the spatio‐temporal dynamics of P. vulgatissima is needed in order to assess the effects of mixed clonal plantings on the management of this pest.2 Distribution patterns of adult P. vulgatissima were monitored over a season at a spatial scale of every tree or every other tree in single clone plantings (monocultures) of three willow clones and in a regular row mixture of these clones.3 Distribution indices (deviation from Complete Spatial Randomness) demonstrated that P. vulgatissima adults were spatially aggregated on favourable clones in the monocultures and the mixture. The degree of aggregation (measured by the k‐parameter of the negative binomial) differed between willow clones. Beetles were highly aggregated at the start of the season, but less so later.4 Dispersal studies of P. vulgatissima adults over time showed a pattern of beetle infestation along rows of the preferred clones in a regularly structured mixture. In the monocultures, movement was less directional.5 Plantation design offers some potential for more effective non‐chemical pest management for P. vulgatissima. Monitoring of the pest must take account of our findings that adults occur in mobile aggregations.
Thermal ecology of Zonocerus variegatus and its effects on biocontrol using pathogens
Authors: Blanford Simon , Thomas Matthew B. , Langewald Jürgen 
Published: March 2003

Summary1 Thermal behaviour of the variegated grasshopper, Zonocerus variegatus, was investigated in the humid tropical zone of southern Benin, west Africa, in the dry seasons of 1996 and 1998. In 1998, investigations included studies of a population of grasshoppers sprayed with an oil‐based formulation of the entomopathogenic fungus Metarhizium anisopliae var acridum.2 Body temperature measurements and observations of thermal behaviour both in the field and on thermal gradients in the laboratory, suggest that Z. variegatus was not an active behavioural thermoregulator. Although it did show shade‐seeking behaviour at high temperatures, no overt behavioural postures or microhabitat selection associated with heat gain and elevation of body temperatures was observed. Moreover, no alterations to thermal behaviour were found in response to infection by Metarhizium.3 Body temperatures exhibited by Z. variegatus in the field will lengthen disease incubation of M. anisopliae var acridum compared with laboratory maintained, constant temperature conditions and may have a significant impact on pathogens with a lower thermal tolerance.4 Habitat structure appeared to be an important factor determining the extent of body temperature elevation. The effect of habitat differences on infection and growth of M. anisopliae var acridum and other entomopathogenic fungi is discussed.
Horizontal transmission of Beauveria bassiana (Bals.) Vuill
Authors: Long David W. , Groden Eleanor , Drummond Francis A. 
Published: March 2003

Summary1 Factors influencing horizontal transmission of the entomopathogen Beauveria bassiana in the Colorado potato beetle (CPB) were examined through a series of laboratory studies.2 Cadaver density, cadaver life stage, ambient temperature and conidial density were the factors manipulated.3 Mortality and sporulation of burrowing CPB prepupae both increased significantly with increased sporulating second‐instar cadaver density on the soil surface.4 Mortality rates were significantly higher when prepupae were released into laboratory arenas containing third‐instar cadavers compared to second‐instar cadavers.5 Mortality and sporulation decreased significantly as temperature increased from 15 °C to 30 °C, however, no temperature‐dependent behavioural response by prepupae could be identified as a potential cause.6 An 86.1% decrease in conidial density per cadaver had no significant effect on mortality or sporulation of prepupae, indicating that this level of environmental degradation of cadavers may not significantly reduce the probability of horizontal transmission.
Elevated CO2 affects the interactions between aphid pests and host plant flowering
Authors: Awmack Caroline S. , Harrington Richard 
Published: March 2003

Summary1 Broad beans (Vicia faba L.) were grown at either ambient (350 μL/L) or elevated (700 μL/L) CO2. Elevated CO2 increased shoot weight by 14% and root weight by 24% compared to ambient, but did not affect flowering.2 A single pea aphid (Acyrthosiphon pisum (Harris)) and its progeny decreased shoot and root weights by 20 and 24%, respectively, at ambient CO2 after 20 days, but did not affect flower number. At elevated CO2A. pisum decreased shoot and root weights by 27 and 34% and flower number decreased by 73%.3 A single glasshouse and potato aphid (Aulacorthum solani (Kaltenbach)) and its progeny had no effect on the growth of bean plants after 20 days at ambient CO2. At elevated CO2, A. solani decreased shoot and root weights by 20 and 18%, and flower number by 60%.4 The large reduction in flowering caused by aphids at elevated CO2 suggests a change in resource allocation within the plants to compensate for aphid infestation.5 Aphid density was unaffected by elevated CO2, although there were significant effects of CO2 on the resulting population structure of both A. pisum and A solani. We suggest that at elevated CO2, aphids appear not to achieve their maximum reproductive potential and their populations are limited by the lower carrying capacity of their host plants.
Evaluation of traps used to monitor southern pine beetle aerial populations and sex ratios
Authors: Cronin James T. , Hayes Jane. L. , Turchin Peter 
Published: March 2003

Summary1 Various kinds of traps have been employed to monitor and forecast population trends of the southern pine beetle (Dendroctonus frontalis Zimmermann; Coleoptera: Scolytidae), but their accuracy in assessing pine‐beetle abundance and sex ratio in the field has not been evaluated directly.2 In this study, we used fluorescent powder to mark pine beetles emerging from six isolated infestations. We then compared estimates of total abundances and proportions of males emerging from within each infestation to the estimates from three types of traps: passive sticky traps (2, 5, 10 and 20 m away from the source of beetles), multi‐funnel traps baited with pine beetle attractants (100 m away) and pine trees baited with attractants (also 100 m away).3 We found that the proportion of males captured in traps was significantly affected by the type of trap used.4 Within an infestation, equal proportions of males and females were marked (0.53 ± 0.02 males; mean ± SE), but the proportions captured in trap trees and passive traps were more female biased (0.42 ± 0.03 and 0.46 ± 0.01 males, respectively). On the other hand, funnel traps provided an estimate of the proportion of males that was nearly identical to the proportion from within infestations (0.51 ± 0.03).5 Numbers of marked beetles captured in traps were uncorrelated with the numbers of marked beetles emerging from the focal infestations. This suggests that traps positioned around an infestation may not be effective at estimating relative abundances of beetles within the infestation.
Rapid gall midge adaptation to a resistant willow genotype
Authors: Glynn Carolyn , Larsson Stig 
Published: March 2003

Abstract 1 We conducted two experiments to investigate why a basket willow Salix viminalis L. genotype, known to be highly resistant to the leaf‐roller gall midge Dasineura marginemtorquens (Bremi), should support very high gall densities in a field plantation at Tälle, south Sweden.2 The first experiment was a field test of the hypothesis of fine‐scale host adaptation in the gall midge/willow system. Support for the hypothesis would be established if midges originating from resistant willows and those originating from nearby susceptible willows differed in their abilities to initiate galls and complete development on resistant plants.3 The objective of the second experiment was to explore whether there was a genetic basis to the trait for virulence in the midge population and to investigate any potential trade‐offs this trait may entail.4 Our results indicate that there was a fine‐scaled microgeographic genetic structure to the midge population at Tälle. Midges originating from resistant plants had a heritable trait that enabled them to establish galls on resistant plants.5 Midges able to initiate galls on the resistant genotype had longer developmental time on the susceptible genotype. This suggests that there is a physiological cost associated with being adapted to the resistant willow genotype.6 We suggest that driving forces behind the observed host adaptation are selection imposed on the midge population by very strong willow resistance and restricted gene flow in the midge populations due to the special life history features of D. marginemtorquens.
Expanding radiation quarantine treatments beyond fruit flies
Authors: Hallman Guy J. 
Published: March 2003

Abstract1 The potential of ionizing radiation as a disinfestation treatment for insects other than tephritid fruit flies is discussed. Radiation quarantine treatments are unique in that insects are not killed immediately but rendered sterile or incapable of completing development.2 The most tolerant insect stage to radiation is that which is most developed. Female insects, but not always mites, are sterilized with equal or lower doses than males.3 Insects irradiated with sterilizing doses usually have shorter longevities than non‐irradiated ones. Low oxygen conditions often increase tolerance to radiation.4 Insects in diapause are not more tolerant of radiation than non‐diapausing ones.5 Some pests of several groups, such as aphids, whiteflies, weevils, scarab beetles, and fruit flies, may be controlled with doses ≤ 100 Gy. Some lepidopterous pests and most mites require about 300 Gy. Stored product moths may require as much as 1 kGy to sterilize, and nematodes could need > 4 kGy.6 Even though application of irradiation to pallet‐loads of produce could mean that up to three times the minimum required dose is applied to the perimeter of the pallet, many fresh commodities tolerate doses required for quarantine security against many quarantined pests. Irradiation is arguably the most widely applicable quarantine treatment from the standpoint of commodity quality.
Deterred oviposition response ofMonochamus alternatus(Coleoptera: Cerambycidae) to oviposition scars occupied by eggs
Authors: Anbutsu Hisashi , Togashi Katsumi 
Published: March 2003

Summary1 The oviposition behaviour and response ofMonochamus alternatusfemales to oviposition scars were investigated in the laboratory.2 Prior to oviposition, females gnawed at the bark surface ofPinus densiflorabolts to make a wound. Then females turned their bodies 180° to position their ovipositors over the wounds and inserted them under the bark through the wounds. After an oviposition, a jelly was deposited while the ovipositor was still inserted. The females then withdrew their ovipositors and rubbed the oviposition scars with the tips of their abdomens.3 When searching females encountered oviposition scars, they stopped walking and drummed the surface and inside of the oviposition scars with their maxillary and labial palpi.4 Eighty‐six percent of females left oviposition scars containing single eggs after the palpation. By contrast, when females encountered oviposition scars containing no eggs, 76% of them began to gnaw at the scars and 64% deposited single eggs. The response to artificial oviposition scars was similar to that to vacant oviposition scars made by the females.5 The results of various observations and experiments showed that the females could recognize oviposition scars and discriminate the scars occupied by single eggs from vacant ones, and suggested that the palpation of oviposition scars was the critical discrimination behaviour, indicating mediation by chemical cues.
Modelling the use of NPV for the biological control of Asian gypsy moth Lymantria dispar invading New Zealand
Authors: Barlow N. D. , Caldwell N. P. , Kean J. M. , Barron M. C. 
Published: March 2003

Summary1 The accidental introduction of the Asian strain of gypsy moth (AGM) Lymantria dispar (L.) to New Zealand poses a major threat to New Zealand's forestry industry. To aid eradication and control decisions in the event of its establishment, a model was developed for the effect of nuclear polyhedrosis virus (NPV) as biological control for AGM in New Zealand.2 The model simulates within‐ and between‐season gypsy moth population dynamics, including temperature‐dependent development, density dependence through predation and resource limitation, and interactions with NPV.3 Following its introduction to New Zealand, AGM is predicted to increase more quickly and have more severe outbreaks than the European strain. In the absence of predators, the model predicts initial outbreaks then damped oscillations to an equilibrium.4 In the model, a single application of NPV (2500 GPIB ha−1) at the time of maximum larval density gave up to 80% suppression of peak larval densities in the following year. The same level of suppression was achieved in the absence of predators.5 In the long term, the model predicted that spraying when an outbreak was just beginning gave best results (a 50–70% reduction of the following two outbreaks). Simulation of threshold spraying resulted in NPV application, on average, every 7 years and suppression of outbreak densities by 40–70%. Following a single application, NPV was maintained in the population as a classical biological control agent, giving approximately a 20% reduction in outbreak densities.6 Eradication of AGM using NPV was possible if larval densities were very low.
Spider abundance and diversity in apple orchards under three insect pest management programmes in Washington State, U.S.A.
Authors: Miliczky Eugene R. , Calkins Carrol O. , Horton David R. 
Published: March 2003

Summary1 Many apple growers in Washington State, U.S.A. use mating disruption (MD) for control of codling moth, Cydia pomonella (Linnaeus). Fewer applications of synthetic, broad‐spectrum insecticides are made in MD orchards than in orchards under conventional (C) management. Spider abundance and diversity in MD, C and certified organic (O) orchards were compared. Spiders inhabiting the trees (arboreal), the understory vegetation, and the ground surface were studied.2 Total arboreal spider density and total understory spider density were significantly higher in O orchards than in MD and C orchards. Many species occurred in both the trees and the understory.3 Arboreal, visually orientated, hunting spiders and arboreal ambushers/runners were significantly more abundant in O orchards compared to C and MD orchards. Visual hunters were significantly more abundant in MD compared to C orchards. Numbers of spiders in two other guilds (web‐makers and nocturnal hunters) showed no statistical differences with respect to orchard management type.4 The highest density of ground surface‐dwelling spiders occurred in one of the O orchards. Two C orchards had higher densities than any MD orchard. Ground surface species were distinct from those in the understory and the trees.5 With one exception, an orchard's arboreal fauna was most similar to that of another orchard under the same type of pest management. Three exceptions were noted among comparisons of the understory faunas. The ground surface‐dwelling fauna of one O orchard was distinctive, whereas that in the second O orchard was similar to the C and MD orchards.6 Reduced use of synthetic, broad‐spectrum insecticides in MD orchards did not result in arboreal spider densities comparable to those found in O orchards. A contributing factor may be that all species were univoltine. Spider populations may thus be severely reduced by even a small number of synthetic, broad‐spectrum insecticide applications and the time required for recovery may be lengthy.
Dynamics of twolined chestnut borerAgrilus bilineatusas influenced by defoliation and selection thinning
Authors: Muzika R. M. , Liebhold A. M. , Twery M. J. 
Published: March 2003

Abstract1 The twolined chestnut borer,Agrilus bilineatus(Coleoptera: Buprestidae), is a major mortality agent of stressed oak trees. However, patterns of abundance and population change are not well understood.2 We studied the spatial and temporal variation in abundance of twolined chestnut borer adults during a gypsy moth,Lymantria dispar(Lepidoptera: Lymnatriidae), outbreak and examined the influence of both defoliation and thinning on twolined chestnut borer abundance.3 In stands that were defoliated by gypsy moth, extensive defoliation occurred in one year, and major overstory tree mortality followed in the next. Most mortality occurred in the year preceding the peak year of twolined chestnut borer abundance and abundance of twolined chestnut borer was positively associated with defoliation and mortality in the previous year.4 Twolined chestnut borers were more frequently associated with poor or fair crown condition trees than trees with good crown condition and were more abundant on members of the red oak group than the white oak group.
Population dynamics of the bird cherry‐oat aphid, Rhopalosiphum padi (L.), during the autumn and winter: a modelling approach
Authors: Morgan Derek 
Published: March 2003

Abstract1 A simulation model was developed to investigate the inter‐relationship of factors influencing the population dynamics of the bird cherry‐oat aphid (Rhopalosiphum padi (L.)) in barley crops during the autumn and winter.2 The model incorporated algorithms describing alate immigration, development and survival of adults and nymphs, fecundity and morph determination in newly born nymphs.3 The model was validated against pest outbreaks in barley fields in south‐east England.4 It simulated accurately the size of the outbreaks with predictions of peak aphid populations within 20% of the observed in all but one case. Similarly, all but one of the year‐sowing date combination predictions of timing of peak abundance fell within 14 days of the observed.5 A sensitivity analysis of the model highlighted the relative importance of various population processes in determining simulated aphid population dynamics; decreasing mortality rates of apterous nymphs by as little as 5% over the autumn and winter increased peak densities by as much as 60‐fold, whereas increasing daily temperatures by only 1 °C more than doubled peak aphid abundance.6 The model identified our understanding of the mechanisms of aphid mortality as a limiting factor in the accurate prediction of R. padi outbreaks in the field.