bluuebunny/crossref_metadata_2025_split huggingface dataset:
Artificial injury experiments on the damaging effect of Leucoptera malifoliella on apple trees
Authors: Baufeld P. , Freier B. 
Published: April 2011

AbstractIn 1986 and 1987 defoliation experiments on the apple cultivar Herma were performed to simulate the occurrence of Leucoptera malifoliella Costa. Those model experiments were based on investigations on the mine size of Leucoptera malifoliella and yield loss on infested and tagged trees. Defoliation carried out by hand showed that heavy leaf loss reduced fruit number. Insufficient nutrient supply due to reduced leaf area and a consequently smaller leaf‐fruit ratio led to a decrease in mean fruit size and total yield. Heavy leaf loss had also an adverse effect on fruit quality components (dry matter substance, viscosity, total sugar and acid content of fruit juice). This was finally reflected in sensory evaluation criteria. Heavy leaf losses also influenced blossom bud differentiation in the blossom set of the following year. Both number of inflorescences and number of blossoms per inflorescence were reduced. The evaluation of the extent of damage of L. malifoliella was based on previous investigations on reduced leaf area. For L. malifoliella a mean mine size of 0.96 cm2 was found. This corresponds to a 4.2% loss of leaf area.The leaf‐fruit ratio is of special importance for the evaluation of the extent of damage of leaf‐damaging pests and was used to derive injury threshold ranges for L. malifoliella. Previous investigations on L. malifoliella infestations and the results from the artificial defoliation experiments enabled the determination of preliminary flexible injury thresholds. Depending on leaf‐fruit ratio, yield level, and leaf miner generation, the thresholds vary between 0.1–2.5 eggs and mines per leaf.
Flight propensity and diapause incidence in five populations of the bark beetle Ips typographus in Scandinavia
Authors: Forsse E. 
Published: April 2011

AbstractEmergence from brood logs, take‐off activity and the duration of tethered flight was recorded in the first laboratory generation of the bark beetle Ips typographus L. (Coleoptera: Scolytidae) from five locations (ca 300 km apart) in Sweden and Denmark. Beetles of northerly origin emerged later from brood logs. This pattern was associated with an increasing proportion on non‐fliers towards the north. After overwintering, both the rate of development of flight activity and the proportion of non‐fliers were the same among populations. Flight duration of fliers was similar among populations and appeared unaffected by outbreak conditions.
Effects of mating status and age on dispersal behavior in the twospotted spider mite, Tetranychus urticae in response to fenvalerate‐treated leaf surfaces
Authors: Suiter K. A. , Gould F. 
Published: April 2011

AbstractEffects of variation in age and mating status on dispersal of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), from fenvalerate‐treated leaf surfaces were investigated. Unmated and mated female mites, 1 to 6 days in age, were scored for walkoff and spindown dispersal response on bean leaves treated with a sub‐lethal, residual dose of fenvalerate. Variation in mite age did not have a pronounced effect on dispersal response. Significant differences in dispersal response due to mating type were observed, yet the mean differences in dispersal response between unmated and mated females was generally small. Our data suggest that the current practice of using mated female mites of unknown age when testing for among‐population differences in dispersal response, in most cases, provides an adequate estimate of population response when differences among treatments in dispersal response are large. However, when testing for within‐population differences in dispersal response, small treatment effects may be more easily measured using a single age class of mites, because this could decrease within‐treatment variance.
The combination of electronic monitoring and video‐assisted observations of plant penetration by aphids and behavioural effects of polygodial
Authors: Hardie J. , Holyoak M. , Taylor N. J. , Griffiths D. C. 
Published: April 2011

AbstractSimultaneous electronic and close‐up video recordings were made of behaviour during the initial 15 min of plant contact by adult, apterous Aphis fabae Scopoli on tick bean seedlings (Vicia faba Moench). Electronic techniques accurately determined stylet penetration of plant tissue and there was a close correlation between penetration and periods during which the insect antennae and body were immobile (r = 0.994, n = 60). Video techniques were then used alone to infer stylet penetration and the behaviour of aphids after various treatments was monitored. In particular, the time to first penetration, the number of penetrations, the mean duration of penetrations and the total time of penetration were observed. Behavioural differences were recorded between tethered (as required for electronic recording) and freely‐moving insects as well as between fed and starved insects. The behaviour of starved aphids placed on beans treated with the plant‐derived antifeedant, polygodial could not be distinguished from aphids on solvent‐treated control beans. However, there were significant differences in behaviour of aphids which had previously been exposed to polygodial on plant or green/yellow paper surfaces for 24 h when compared with insects exposed to solvent alone. The possible modes of action of polygodial are discussed.
Intensification de la diapause embryonnaire d‘Archanara sparganii par la température: Incidences écologiques
Authors: Galichet P. F. , Girard R. , Cousin M. 
Published: April 2011

RésuméL'incubation des oeufs d'Archanara sparganii, Esper (Lepidoptera: Noctuidae) s'étend sur 8 à 9 mois dans les conditions naturelles. Elle est temporairement interrompue par une diapause qui intervient à un stade précoce de l'embryogénèse et se prolonge de l'été à la fin de l'hiver. Au laboratoire, l'incubation est néanmoins possible à température constante entre 8 et 21 °C. Une étude expérimentale a montré que l'intensité de la diapause s'accroft lorsque la température en début d'incubation est portée pendant 15 jours de 11 °C à 15 °C et 21 °C. Aucun des modèles expérimentaux faisant intervenir la température n'a permis d'éviter totalement la diapause. La durée de celle‐ci a néanmoins été réduite des trois quarts dans certaines circonstances, rendant possible l'éclosion des larves avant l'hiver. Ces résultats servent à interpréter les altérations du cycle biologique du nord au sud de la distribution d'A. sparganii. La perte rapide de réceptivité de Typha spp. à l'égard des larves jeunes justifie par ailleurs une entrée en diapause précoce de l'espèce sous climat méditerranéen.SummaryArchanara sparganii. Diapause intensification induced by temperature in the eggs of Archanara sparganii. Ecological implicationsEgg incubation of A. sparganii Esper (Lepidoptera: Noctuidae) requires 8 to 9 months under natural conditions extending from the early summer to the early spring of the next year. The egg development is interrupted by an obligatory diapause at an early stage of embryogenesis. The whole of the egg's incubation can be concluded at a constant temperature within the range 8 °C–21 °C. The intensity of diapause has been found to be directly correlated with rising temperatures from 11 °C to 21 °C, applied for 15 days immediately after egg laying. None of the experimental temperature regimes tested prevented the occurrence of diapause, the incubation period could however be reduced to a quarter of its natural duration thus allowing larvae to hatch before winter. These results afford a better understanding of the life cycle modifications observed throughout the geographical range. A rapid loss in the receptivity of the main host plant towards young larvae makes of an early diapause a necessity under the mediterranean climate.
Spatial distribution and sequential sampling of adults of Gonocephalum macleayi and Pterohelaeus darlingensis in different cropping regimes
Authors: Allsopp P. G. , Forrester N. W. 
Published: April 2011

AbstractCounts of adults of the false wireworms Gonocephalum macleayi (Blackburn) and Pterohelaeus darlingensis Carter in pitfall traps in burnt, mulched and sorghum treatments conformed to Taylor's power law. Within a species there were no significant differences in distributions of counts of either sex in any habitat but G. macleayi were more aggregated than P. darlingensis (Taylor's b 1.35 and 1.26, respectively). Relationships to determine sample sizes for fixed levels of precision and fixed‐precision‐level stop lines for sequential sampling are developed for each species using Taylor's parameters for combined data over all habitats.
Effect of shape, size and color on selection of oviposition sites by Chaetorellia australis
Authors: Pittara I. S. , Katsoyannos B. I. 
Published: April 2011

AbstractThe effect of shape, size and color on the selection of oviposition sites by females of Chaetorellia australis Hering (Diptera, Tephritidae) originating from infested yellow starthistle (YST) Centaurea solstitialis L. (Asteraceae, Cardueae) heads, was studied in the laboratory by direct observation of females sitting on or attempting to oviposit into different objects. Artificial substrates made of yellow‐colored parafin wax mimicking the natural oviposition sites (floral buds of YST), were used to study the effect of shape and size. The results revealed that spherical and conical objects of a total surface area of 310 mm2, were visited more frequently than cylindrical and cubical ones of the same surface area. Also more females were observed and more oviposition attempts were recorded on spheres of 5 and 10 mm diameter than of 15 and 20 mm diameter. Yellow and orange dry YST heads, colored by dipping in molten colored ceresin wax, were preferred for oviposition to black, green, blue, red and white ones. The observed preference for certain colors depended primarily on the color hue and not on the intensity of the total reflected light. The females responded positively to hues reflecting maximally between 560 and 610 nm, optimum at 590 nm, while hues reflecting below 540 nm and especially between 400 and 500 nm appeared to have no positive effect.
The dynamics of leaf surface wetness of sorghum seedlings in relation to resistance to the shoot fly, Atherigona soccata
Authors: Nwanze K. F. , Sree P. S. , Butler D. R. , Reddy D. D. R. , Reddy Y. V. R. , Soman P. 
Published: April 2011

AbstractIn quantitative measurements of leaf surface wetness (LSW) of the central whorl leaf of sorghum seedlings in August (rainy season) and November (post‐rainy season), the highest amount (6.29 mg of water) was recorded in August in the shoot fly Atherigona soccata (Diptera: Muscidae), susceptible sorghum genotype CSH 1, while the lowest (0.07 mg) was recorded in November in the resistant genotype IS 18551. Studies on diurnal fluctuation revealed that LSW was lowest at sunset, was highest between 02.00 and 04.00 h (closely corresponding with hatching of shoot fly eggs) and dropped before sunrise. This fluctuation was associated with the evaporation of water from the plant during the night. More LSW accumulation occurred during the main crop season (June‐October) than in the post‐rainy season (November‐April). Annual fluctuation of LSW followed trends similar to the population dynamics of shoot fly and crop infestation and were correlated with rainfall, temperature and relative humidity. Measurements of leaf temperature and the vapour pressure gradient between the leaf and the air indicated that leaf surface water originates from the plant. This was further supported by the different amounts of LSW on susceptible and resistant cultivars with similar microclimatic conditions.
Demographic analyses of organophosphate‐resistant and susceptible strains of greenhouse whitefly, Trialeurodes vaporariorum, on three cotton cultivars
Authors: Omer A. D. , Leigh T. F. , Carey J. R. , Granett J. 
Published: April 2011

AbstractLaboratory experiments were conducted using organophosphate‐resistant and susceptible strains of greenhouse whitefly, Trialeurodes vaporariorum Westwood, to assess age‐specific vital rates in individually‐held adults, and development and survival in preadults on three cotton cultivars at 27 ± 1 °C, 50 ± 10% RH, and a photoperiod of 16:8 (L:D). Female whiteflies lived longer than males, with a maximum life expectancy of 29 days. Heaviest egg laying occurred at ages between 7 and 18 days when individual whiteflies laid > 10 eggs/day. Greenhouse whitefly populations doubled weekly, with stable age distribution of 63% eggs, 28% larvae, 5% pupae, and 4% adults. Analysis of various life history parameters that combine aspects of survival, developmental rates, and fecundity indicated no consistent differences in reproductive fitness between the two greenhouse whitefly strains. Of the three cotton cultivars tested, Pima S‐6 was most susceptible, Acala SJ‐2 was intermediate and Gumbo 500 was most resistant to greenhouse whitefly. Resistance of Gumbo 500 was expressed as slower developmental rates, reduced survival to adulthood, lower reproductive rates, and lower intrinsic rate of increase.
Effects of azadirachtin after systemic uptake into Brassica oleracea on larvae of Pieris brassicae
Authors: Arpaia S. , VAN Loon J. J. A. 
Published: April 2011

AbstractPetioles of intact cabbage leaves were placed in azadirachtin solutions for 24 h. Azadirachtin or active metabolites of this compound appeared to be translocated systemically as performance of first instar larvae of Pieris brassicae L. placed on disks from those leaves was affected. The position within a leaf from which disks were excised did not affect the extent of these effects, indicating a homogeneous distribution of active compounds in the laminar tissue. At doses ranging from 1–10 ppm of azadirachtin in the solution taken up by the leaves, gain of larval fresh weight and leaf area consumed were reduced. These effects were dose dependent up to 60–90 ppm. At 10 ppm and higher doses no larva reached the second instar within 72 h. Mortality during the 72 h period was highest at 10 ppm, due to the coincidence of lethal action with ecdysis in combination with the effect on developmental rate. Azadirachtin solutions applied directly to the surface of leaf disks in order to produce known doses on a leaf fresh weight basis gave results similar to the systemic treatment for weight gain, leaf area consumed and developmental rate, while mortality was higher in the latter treatment.
Foraging of Rhagoletis pomonella flies in relation to interactive food and fruit resources
Authors: Averill A. L. , Prokopy R. J. 
Published: April 2011

AbstractUp to this point, quantitative aspects of the resource foraging behavior of tephritid fruit flies have been examined at what has been termed the first level of a four‐level hierarchical framework. This framework has been constructed to facilitate an operational approach to investigating foraging behavior within a dynamic, state‐variable mode of analysis. First‐level examination involves tracking the behavior of tephritids in situations comprised of a single type of essential resource where just a single factor shaping foraging behavior is manipulated experimentally. Here, we investigated the foraging behavior of Rhagoletis pomonella (Walsh) flies at the second operational level in the hierarchy: a semi‐natural environment comprised of patches of potted host trees that simultaneously harbored two types of essential resources: food and oviposition sites. Mature, fed females that were marked and released into the center tree of five‐tree patches remained significantly longer and laid significantly more eggs over two days in patches containing both food (protein and carbohydrate) and oviposition sites (hawthorn fruit) than in patches containing oviposition sites alone. Our findings lead us to speculate that odor of abundant natural food could result in accumulation of both sexes in species of trees whose fruit emit no attractive odor and are not permanent hosts of R. pomonella, but which could receive eggs and support larval development of temporary populations of food‐seeking flies.
Mating disruption for control of damage by codling moth in Virginia apple orchards
Authors: Pfeiffer D. G. , Kaakeh W. , Killian J. C. , Lachance M. W. , Kirsch P. 
Published: April 2011

AbstractPolyethylene dispensers (Shin Etsu) containing 172 ml of the sex pheromone, (E,E)‐8–10‐dodecadien‐1‐ol (63%), dodecenol (31%) and tetradecenol (6%), of codling moth (CM), Cydia pomonella (L.), were placed in apple orchards in Virginia. Two blocks of about 2 ha each were treated in 1989, and three in 1990. Dispensers were placed in trees at a density of 1000/ha shortly after apple bloom. Male orientation to pheromone traps was almost totally disrupted (a few males were captured at high population densities). In 1989, the Daleville pheromone‐treated block had 0.9% and 0.8% CM‐injured fruit in the center and edge, respectively; 0% and 39.5% injured fruit were found in the conventional control and abandoned blocks, respectively. The Criglersville orchard (‘organically’ managed, with high CM density) CM harvest injury was 16.0%, 16.5%, 34.5%, and 26.5% in the pheromone‐treated center and edge, organic control and abandoned blocks, respectively. In 1990, the Daleville CM harvest injury was 4.7%, 7.3%, 1.1%, 0.3% and 58%, in the pheromone‐treated center and edge, control center and edge, and abandoned blocks, respectively (possible reasons for the high injury in this block are discussed). Harvest injury in the Fincastle pheromone‐treated and control blocks were 0.7% and 0%, respectively. The Criglersville orchard yielded 17%, 19% and 20% CM‐injured fruit at harvest in the pheromone‐treated, organic control and abandoned blocks, respectively. Pheromone release rate was calculated as 37 mg/ha/h in 1989.
The responses of the cabbage seed weevil (Ceutorhynchus assimilis) to the odour of oilseed rape (Brassica napus) and to some volatile isothiocyanates
Authors: Bartlet E. , Blight M. M. , Hick A. J. , Williams I. H. 
Published: April 2011

AbstractThe responses of the cabbage seed weevil, Ceutorhynchus assimilis Payk. (Coleoptera: Curculionidae) to volatiles from oilseed rape (Brassica napus L.) were tested using a linear track olfactometer. Weevils were attracted towards the odour of rape during a short period before diapause and for most of their post‐diapause life. Odours from both the flowering and green parts of the plant were attractive, but the odour of a non‐host plant (Bellis perennis L.) was not. An entrainment extract of flowering rape volatiles in pentane was attractive, but significantly less so than the odour of flowering rape itself. Attraction was found to 3‐butenyl and 4‐pentenyl isothiocyanate (NCS), but not to 2‐phenylethyl isothiocyanate. A mixture of the three NCSs was more attractive than the individual NCSs. However, the concentration required to produce a response was still relatively high. Isothiocyanates, along with other volatiles from rape, probably play a role in host plant recognition by the seed weevil.
Sex pheromones in the cereal aphid parasitoids Praon volucre and Aphidius rhopalosiphi
Authors: Decker U. M. , Powell W. , Clark S. J. 
Published: April 2011

AbstractLaboratory and field experiments provided evidence for the release of sex pheromones by virgin female Praon volucre Haliday and Aphidius rhopalosiphi De Stefani‐Perez (Hymenoptera: Braconidae, Aphidiinae). In Petri dish biosassays, rubber or vermiculite models treated with crude virgin female extracts were frequently approached by males and elicited rapid wing‐fanning behaviour and copulation attempts. Delta‐shaped water traps containing live virgin females caught large numbers of conspecific males when placed in winter wheat crops. Trapping slightly below crop height resulted in higher catches than trapping above the crop canopy.
Variation in flight response of the specialist parasitoid Macrocentrus grandii Goidanich to odours from food plants of its European corn borer host
Authors: Udayagiri Sujaya , Jones Richard L. 
Published: April 2011

AbstractThe specialist parasitoid Macrocentrus grandii Goidanich (Hymenoptera: Braconidae) appears to parasitize its polyphagous host, European corn borer (Ostrinia nubilalis (Hübner)) (Lepidoptera: Pyralidae), in only certain habitats. To determine whether it differed in its olfactory response to host‐habitat odours, volatiles from four plants were isolated using Tenax. Wind tunnel bioassays of the extracts revealed that, besides corn which was tested in an earlier study, olfactory stimuli for attraction of M. grandii females were present in potato and snap bean but not in pepper or soybean. To further characterize the response to pepper and soybean, these extracts were bioassayed in combination with an attractive extract. The results indicated that pepper volatiles evoked a neutral response in M. grandii while response to soybean volatiles appeared to be neutral or slightly negative. The innate response to soybean volatiles was altered to one of attraction after oviposition experience on soybean. Seven days after oviposition, experienced females continued to respond positively to soybean volatiles. Components of soybean volatiles responsible for the change in flight behaviour resulting from oviposition experience were eluted by nonpolar and slightly polar solvents. These results support the idea that plant odour may be a factor determining the range of plants on which M. grandii parasitizes its host. The study indicates the occurrence of associative learning of plant‐related volatiles during oviposition in M. grandii, and suggests the involvement of diverse plant compounds in the learning process.
Reduction of black vine weevil larval growth by vesicular‐arbuscular mycorrhizal infection
Authors: Gange A. C. , Brown V. K. , Sinclair G. S. 
Published: April 2011

AbstractLarvae of Otiorhynchus sulcatus (black vine weevil) were reared at three densities (zero, two or eight), on plants of Taraxacum officinale (dandelion) with and without infection by the mycorrhizal fungus Glomus mosseae. On plants without the fungus, survival of larvae to late final instar was 84%, but this was only 43% on infected plants. The differential survival of larvae was evident in their effects on plant biomass. Significant interactions were found between larval density and infection, indicating that mycorrhizal presence mitigated the effects of herbivory at the low larval density. Infection by G. mosseae thus conferred some degree of resistance in roots to this insect and the consequences of this for horticultural and natural situations are discussed.