20 research outputs found

    Ecology and management of plum curculio, Conotrachelus nenuphar [Coleoptera :Curculionidae], in apple orchards

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    Le charançon de la prune (Conotrachelus nĂ©nuphar) est un insecte originaire de l'AmĂ©rique du Nord. Il s'attaque aux fruits Ă  pĂ©pins et Ă  noyaux de l'est des États-Unis et du Canada. Il est un ravageur prĂ©pondĂ©rant en vergers de pommiers (Maluspumila) au QuĂ©bec. Au printemps, les adultes se dĂ©placent de leurs sites d'hibernation, localisĂ©s principalement dans les boisĂ©s, vers les vergers. Avant la nouaison, l'activitĂ© de ces insectes est surtout nocturne, mais elle s'Ă©tend Ă  toute la journĂ©e dĂšs l'apparition des fruits. Les larves quittent le fruit au moment de la chute physiologique, et la pupaison s'effectue dans le sol. La nouvelle gĂ©nĂ©ration d'adultes apparaĂźt en aoĂ»t, et se nourrit de fruits jusqu'Ă  l'automne, puis retourne vers les sites d’hibernation. Plusieurs Ă©lĂ©ments de la bio-Ă©cologie du charançon sont mĂ©connus, notamment les relations entre l’insecte et l’hĂŽte, le comportement, la dispersion, le mode de dĂ©placement, la reconnaissance des plantes hĂŽtes et des sites d’hibernation, l’orientation, et les seuils Ă©conomiques. Il n’existe actuellement aucune mĂ©thode fiable pour dĂ©pister ce charançon, et aucun moyen biologique de lutte contre ce ravageur. Cependant, des Ă©tudes rĂ©centes sur le comportement et l’activitĂ© du charançon de la prune en conditions semi-naturelles et naturelles pourraient permettre le dĂ©veloppement de stratĂ©gies de lutte plus efficaces. Ces travaux sont prĂ©sentĂ©s ici de mĂȘme qu’une revue des mĂ©thodes de lutte (chimique, biologique, gĂ©nĂ©tique, mĂ©canique et culturale) envisageables contre le charançon de la prune.Plum curculio (Conotrachelus nenuphar) is a native pest of pome and stone fruit in eastern North America. It is a key pest of apple (Malus pumila) orchards in Quebec. In spring, adults disperse primarily from woodland overwintering sites to apple orchards. Before fruit set, the beetles are mainly nocturnal. As fruits become available for oviposition, adults extend their activity to the daytime. Full grown larvae found in dropped apples in June (June drop) enter the soil to pupate. The summer brood emerges in August, feeds on the remaining fruit throughout the fall and then disperses to suitable overwintering sites. Little is known of its community and host plant relationships, dispersal behavior, factors influencing its mode of locomotion, choice of food sources, overwintering sites, micro-habitat selection, orientation, and action threshold. Commercially available biocontrol agents are not effective, and convenient and reliable monitoring techniques for the timing of sprays have not been developed. However, recent field and insectary studies on the behavior and activity of plum curculio adults may allow us to improve the efficiency of control strategies. These findings are presented here, together with their implications for control of the plum curculio by modifying its habitat, and by better timing and location of sprays and other interventions. This paper also includes brief reviews of biological controls, insect growth regulators, and genetic controls for plum curculio

    Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure.

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    Obesity is caused by a prolonged positive energy balance <sup>1,2</sup> . Whether reduced energy expenditure stemming from reduced activity levels contributes is debated <sup>3,4</sup> . Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor
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