A note on the detection of the carrot weevil in Nova Scotia

Le charançon de la carotte, Listronotus oregonensis [Coleoptera: Curculionidae], est un ravageur important des cultures de légumes dans le nord-est de l'Amérique du Nord. Cette espèce n'avait cependant jamais été détectée auparavant dans les Maritimes ou à Terre-Neuve. En 1985, 1986 et 1988, des tentatives de détection de ce ravageur en Nouvelle-Ecosse ont été infructueuses. En 1992, des pièges thigmotactiques faits de plaquettes de bois et appâtés avec des carottes fraîches, ont été utilisés dans trois champs de carottes (Daucus carota), et six spécimens ont été capturés durant la migration printanière de l'insecte entre ses sites d'hivernation et un champ de carottes situé près de Great Village, en Nouvelle-Ecosse.The carrot weevil, Listronotus oregonensis [Coleoptera: Curculionidae], is a significant pest of vegetable crops in northeastern North America. However, the species had not been previously detected in Atlantic Canada. In 1985,1986, and 1988, attempts to detect this pest in Nova Scotia were unsuccessful. In 1992, in one of three carrot (Daucus carota) fields monitored using thigmotactic wooden-plate traps baited with fresh carrots, six individuals were captured during the spring migration of the inseetfrom overwintering sites into a carrot field near Great Village, Nova Scotia

Fracture through cavitation in a metallic glass

The fracture surfaces of a Zr-based bulk metallic glass exhibit exotic multi-affine isotropic scaling properties. The study of the mismatch between the two facing fracture surfaces as a function of their distance shows that fracture occurs mostly through the growth and coalescence of damage cavities. The fractal nature of these damage cavities is shown to control the roughness of the fracture surfaces

Comparaison de plans d’échantillonnage séquentiel binomial et de type Iwao pour le dépistage du thrips de l’oignon (Thrips tabaci) [Thysanoptera : Thripidae] sur l’oignon

Des différences transitoires de densité du thrips de l'oignon (Thrips tabaci) ont été observées entre les bordures et le centre de certains champs d'oignon (Allium cepa). Les populations de thrips sont constituées d'agrégats dispersés de façon contagieuse à l'intérieur des champs d'oignon. Deux types de plans d'échantillonnage séquentiel ont été établis pour le T. tabaci sur l'oignon: plan binomial basé sur la présence d'au moins 5 thrips plant d'oignon-1 et plan de type Iwao nécessitant le décompte de tous les thrips présents. Les limites d'acceptation de ces plans ont été calculées pour des seuils économiques de 0,9 et 2,2 thrips feuille-1 Ces plans ont été validés dans des champs abritant des populations entre 0,01 et 32,33 thripsfeuille-1. Les plans de type binomial se sont avérés aussi fiables que les plans séquentiels avec des taux d'erreur ne dépassant jamais 4%, ce qui est inférieur aux niveaux théoriques choisis de 5 et 10%. De bonnes prises de décision ont été obtenues dans 90,4 et 83,6% des cas à l'aide des plans par décompte, et dans 84,8 et 82,4% des cas à l'aide des plans binomiaux pour les seuils de 0,9 et 2,2 thrips feuille-1, respectivement. Le nombre moyen d'échantillons à prélever pour prendre une décision oscille entre 10 et 14 plants d'oignon selon le plan employé. L'emploi des plans binomiaux peut entraîner des réductions de l'effort de comptage des thrips pouvant atteindre jusqu'à 62 et 88% pour les seuils de 0,9 et 2,2 thrips feuille-1, respectivement.Transient differences in onion thrips (Thrips tabaci) densities were observed between the margins and the centre of some onion (Allium cepa) fields. Onion thrips populations consist in aggregates contagiously dispersed within onion fields. Two types of sequential sampling plans were established for T. tabaci in onions: a binomial plan based on the presence of 5 thrips plant-1, and one of the Iwao type, requiring counts of aol thrips present. Acceptation boundaries for these plans were calculated for economic thresholds of 0.9 and 2.2 thrips leaf-1. Plans were validated in fields with thrips populations varying between 0.01 and 32.33 thrips leaf-1. E3 binomial sequential sampling plans were found to be as reliable as plans requiring counts of all thrips, with an error rate not exceeding 4%, a level below the theoretical error rates of 5 and 10% used in the calculations. Correct decisions were reached in 90.4 and 83.6% of the situations with plans requiring counts of all thrips, and in 84.8 and 82.4% of the situations with binomial plans for economic thresholds of 0.9 and 2.2 thrips leaf-1, respectively. The average number of samples needed to reach a decision varied between 10 and 14 plants according to the plan used. Use of binomial plans can save up to 62 and 88% of the counting effort for thresholds of 0.9 and 2.2 thrips leaf-1, respectively

Yield reductions in grain maize associated with the presence of European corn borer and Gibberella stalk rot in Québec

L'effet d'une infestation de la pyrale du maïs (Ostrinia nubilalis) [Lepidoptera: Pyralidae] et d'une infection de la fusariose des tiges causée par Gibberella zeae sur le rendement de huit lignées de maïs grain (Zea mays), de deux hybrides commerciaux et de six hybrides expérimentaux a été évalué de 1975 à 1980. Trois critères ont été utilisés: la criblure du feuillage, les dégâts totaux des plantes à la récolte et le rapport de la longueur des galeries creusées par les chenilles de pyrale dans les tiges sur la hauteur totale du plant. Pour la plupart des critères, les cultivars étaient significativement différents et l'infestation artificielle de pyrale du maïs a eu un effet presqu'à chaque année. Bien que le G. zeae ait eu un effet significatif sur les dégâts totaux à la récolte et le rendement en grain du maïs, aucune relation n'a pu être établie entre la maladie et la pyrale du maïs.The impact of European corn borer (Ostrinia nubilalis) [Lepidoptera: Pyralidae] infestation and stalk rot infection caused by Gibberella zeae on yield of eight grain maize (Zea mays) inbreds, two commercial and six experimental hybrids was evaluated from 1975 to 1980. Three criteria were used: leaf feeding, total plant damage at harvest and tunnel length/plant height ratio. For most criteria, the cultivars were significantly different and the artificial European corn borer infestation had an effect almost every year. Although G. zeae can have a signifiant effect on plant damage at harvest and yield of grain maize, no consistent link was found between stalk rot and European corn borer

Susceptibility of apples to damage by Lygocoris communis and Lygus lineolaris (Hemiptera : Miridae)

Les dommages causés par les larves et les adultes du Lygocoris communis et du Lygus lineolaris aux pommiers (cv. Mclntosh) ont été évalués au moyen de cages de mousseline placées sur des branches de pommiers. Chaque larve de L. communis placée en cage au calice a endommagé une moyenne de 2,1 pommes alors que chaque adulte placé en cage à la nouaison en a endommagé 2,0. Les dommages causés par les jeunes larves (1er, 2e et 3e stades) ont été plus importants que ceux causés par les vieilles larves (4e et 5e stades) et les adultes. Chaque adulte hivernant de L. lineolaris a détruit une moyenne de 4,5 bourgeons à fruits. Chaque adulte de L. lineolaris a endommagé une moyenne de 4,0 pommes lorsque l'attaque avait lieu du stade du pré-bouton rose à la pleine floraison.Damage to apples (cv. Mclntosh) caused by nymphs and adults of Lygocoris communis and Lygus lineolaris was evaluated by placing insects in sleeve-cages on apple-bearing branches. Each nymph of L. communis placed in the cage at petal fall damaged an average of 2.1 apples whereas each adult placed in the cage after fruit set damaged 2.0 apples. Damage by young nymphs (1st, 2nd and 3rd instars) was severe whereas damage caused by old nymphs (4th and 5th instars) and adults was light. Each over wintered adult of L. lineolaris damaged an average of 4.5 fruit clusters. Each adult damaged an average of 4.0 apples when they attacked from tight-cluster to full-bloom stage

Bone microarchitecture in human foetuses

articleBone microarchitecture is receiving increasing attention in theassessment of the biomechanical properties of bone. While it iswell characterized in normal and pathologic human subjects,few quantitative data are available in human fetal development.In this paper, quantitative parameters of bone microarchitecturein developing human bone are reviewed from the literature andsupplemented by new data from the femoral metaphysis of hu-man fetuses. The samples were imaged using synchrotron radi-ation 3D micro-CT and processed using customized analysismethods. This technique provides 3D model independent mor-phometric parameters, anisotropy, connectivity and geometrycharacteristics, as well as information on mineralization.The morphometric parameters obtained on fetal vertebrae andfemurs evidenced a dense trabecular structure as comparedto that of young adults. The histomorphometric and the 3D mi-cro-CT analysis were consistent to show a significant in-crease of trabecular bone volume with gestational age. Tra-becular bone was found isotropic in vertebral bodies andanisotropic in femoral metaphysis, demonstrating a radialgrowth in vertebrae, and a longitudinal spreading out in longbones such as the femurs. Trabecular thickness in the maturebone of vertebral body and femoral metaphysis was around100 μm, which was in agreement with histomorphometric eval-uation. In the femoral metaphysis, three-dimensional analysisconfirmed the thickening of trabeculae with the distance tothe growth plate, and an estimated rate of thickening around 3μm/day previously obtained in histomorphometry. The 3D net-work was highly connected, and our new geometrical analysistechnique showed a strong prevalence of rod structure ascompared to the plate structure in cancellous bone

The detection of Anaphes sp. nov. [Hymenoptera : Mymaridae], an egg parasitoid of the carrot weevil in Nova Scotia

Les guêpes Anaphes victus (Huber) et Anaphes listronoti (Huber) [Hymenoptera : Mymaridae] parasitent 50% des oeufs du charançon de la carotte, Listronotus oregonensis (Le Conte) [Coleoptera : Curculionidae] au Québec et en Ontario. Des essais de piégeage en Nouvelle-Ecosse de l'un ou l'autre de ces parasites en exposant des oeufs du charançon de la carotte n'ont pas réussi.Cependant, 48 spécimens d'une nouvelle espèce de guêpe, Anaphes sp. nov. [Hymenoptera : Mymaridae], ont été capturés dans des champs de carotte (Daucus carota) en Nouvelle-Ecosse, en utilisant des carottes infestées en chambre de croissance par des oeufs du charançon de la carotte. Anaphes sp. nov. se distingue des autres parasites du charançon de la carotte par des caractéristiques de la paire d'ailes antérieure. Anaphes sp. nov. possède un rapport longueur : largeur plus grand que 7 : 3 pour l'aile antérieure alors que chez A. victus et A. listronoti, ce même rapport est plus petit que 6: 7.The wasps Anaphes victus (Huber) and Anaphes listronoti (Huber) [Hymenoptera : Mymaridae] parasitize 50% of the eggs of carrot weevil, Listronotus oregonensis (Le Conte) [Coleoptera : Curculionidae] in Quebec and in Ontario. Attempts to detect either of these egg parasites from exposed carrot weevil eggs in Nova Scotia were unsuccessful. However, 48 individuals of a new species of parasitic wasp, Anaphes sp. nov. [Hymenoptera : Mymaridae], were detected in carrot (Daucus carota) fields in Nova Scotia, using carrots infested in growth chambers with carrot weevil eggs. Anaphes sp. nov. is distinguishable from the other parasites of the carrot weevil by characteristics of the forewing. Anaphes sp. nov. has a forewing length : width ratio greater than 7 :3 while A. victus and A. listronoti have a forewing length : width ratio of less than 6 : 7

An autoparasitoid wasp, inferior at resource exploitation, outcompetes primary parasitoids by using competitor females to produce males

1. Autoparasitoids are intraguild consumers that attack and kill heterospecific and conspecific parasitoids as well as immature stages of hemipteran hosts, such as aphids, whiteflies and soft scales. Field experiments assessing the importance of interspecific competition between autoparasitoids and primary parasitoids, as well as its impact on herbivore suppression, are scarcely found in the ecological literature. 2. Using field data from 40 olive orchards, this study examined the mechanisms that regulate: (i) the interspecific competition between primary parasitoids of the genus Metaphycus and the autoparasitoid Coccophagus lycimnia; and (ii) the density of their shared herbivore host, the soft scale Saissetia oleae. 3. Metaphycus parasitoids used smaller hosts than C. lycimnia, yet did not outcompete C. lycimnia. On the other hand, C. lycimnia preferred to use Metaphycus females as secondary hosts for producing males rather than their own females. This preference might explain why the autoparasitoid negatively affected the density of the primary parasitoids. 4. Parasitism by the autoparasitoid C. lycimnia at the beginning of the season was the sole variable positively related to host mortality throughout the season, showing its greater effect on herbivore suppression. 5. In this study, an autoparasitoid, inferior at resource exploitation, was shown to outcompete a primary parasitoid without disrupting herbivore suppression.info:eu-repo/semantics/publishedVersio

Comparison of eta and eta' production in the pp -> pp eta(eta') reactions near threshold

The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model.Comment: 10 pages, Latex with 3 eps figure