虱螨脲对棉铃虫的生物活性及应用研究

试验测定了虱螨脲对棉铃虫的室内生物活性和田闻防治效果。结果表明,虱螨脲具有较强的杀卵作用。在50mg／L浓度下。棉铃虫1日龄卵死亡率达到87．30％;对棉铃虫2～5龄幼虫具有较高的胃毒活性,其LC50分别为0．7434mg／L、1．9669mg/L、2．0592mg／L和2．6945mg／L。田间试验结果表明。在卵高峰期至初孵期用药,对棉铃虫有较高的防治效果,药后7d．用50g/L虱螨脲EC450mL/hm2、600mL／hm2防治效果分剐为89．3％、90．2％。     

The effect of lufenuron, a chitin synthesis inhibitor, on oogenesis of Rhodnius prolixus

The effects of lufenuron, a chitin synthesis inhibitor, on oogenesis of Rhodnius prolixus were evaluated. Lufenuron-treated females lay eggs that are pink, but change color with time, acquiring a gray color. The eggs are abnormal in shape and become dehydrated. The percentage of eggs that hatch is decreased compared with the eggs from non-treated females. Digestion of ovaries with KOH yielded an insoluble white material, which was identified as chitin based on infrared and proton NMR spectral analyses along with standard commercial chitin. Glucosamine was detected by HPLC as the major product of acid hydrolysis of the KOH-insoluble material prepared from the ovary. Furthermore, presence of chitin in ovary was confirmed through fluorescent microscopy technique using a wheat germ agglutinin probe and by re-treatment with Streptomyces griseus chitinase that resulted in reduction of chitin-derived fluorescence. Micrographs of ovaries, from animals treated with lufenuron, showed some space between the follicular epithelium and the oocyte membrane. The in vivo incorporation of radioactive N-acetylglucosamine into chitin was inhibited by the presence of lufenuron. These data suggest that chitin present in ovaries of R. prolixus is an important component of the eggs and is involved in oogenesis. Exposure to lufenuron reduces the size of oocytes, number of chorionated oocytes, and also the incorporation of N-acetylglucosamine into chitin in the ovaries. In addition, lufenuron-induced oosorption, decreased the number of eggs laid, modified egg shape and color and reduced the viability of the eggs. Therefore, chitin or chitin-like component of ovaries may be considered as a new target for controlling R. prolixus populations.     

The Use of Insect Development Inhibitors as an Oral Medication for the Control of the Fleas Ctenocephalides felis, Ct. canis in the Dog and Cat

Résumé— Il existe deux inhibiteurs de croissance des insectes (ICI) sous forme orale pour le contrôle des puces. Le lufénuron s'administre une fois par mois à la dose de 10 mg/kg chez le chien et 30 mg/kg chez le chat. La cyromazine s'administre quotidiennement à la dose de 10 mg/kg en association avec la diethylcarbamazine chez le chien. Aucun des deux produits n'est actif sur la puce adulte, mais cause plutôt une interruption de la production de chitine normale par différents modes d'actions spécifiques. Ceci entraine la mort des formes immatures de puces. Par conséquent, les 2 produits contrôle l'infestation par les puces adultes sur l'animal par le biais de l'élimination des formes immatures présentes dans le milieu. Il existe un délai de 6 à 8 semaines entre 1'administration d'inhibiteurs de croissance des insectes (ICI) et la reduction du nombre de puces adultes sur les animaux traités. Cette période réfractaire est due à la survie de puces immatures présentes dans le milieu avant le traitement aux ICI; elle peut être réduite si l'on démarre le traitement oral par les ICI simultanément à un traitement insecticide du milieu environnant et de l'animal. [Shipstone, M. A., Mason, K. V. The use of Insect Development Inhibitors as an oral medication for the control of the fleas Ctenocephalides felis, Ct. canis in the dog and cat (Utilisation d'inhibiteurs de croissance des insectes sous forme orale pour le contrôle des puces Ctenocephalides felis, Ct. canis chez le chien et le chat). Resumen— Existen dos inhibidores del desarrollo de insectos (ICI) para el control de pulgas. El Lefenuron se administra una vez al mes a una dosis de 10 mg × Kg^-1 en perros y 30 mg × Kg^-1 en gatos. La Ciromacina se administra diariamente a una dosis de 10 mg × Kg^-1 en combinación con citrato de dietilcarbamacina en perros. Ninguno de estos compuestos produce efecto en pulgas adultas, sino que causa una interrupción en la producción normal de quitina por distintos mecanismos de acción. Ello causa la muerte del parásito en estadíos de inmadurez y crecimiento. Así, ambos controlan la infestación por pulgas adultas en el animal mediante la eliminación de estadíos vitales de la pulga. Existe un espacio de tiempo de 6–8 semanas entre el inicio de la aministración de ICA y la reducción del número de pulgas en animales tratados. Ésto et debido a la supervivencia de pulgas inmaduras que se encontraban en el entorno antes del inicio del tratamiento con ICI; este periodo de tiempo se puede reducir iniciando el tratamiento oral con ICI junto con tratamiento insecticida de la vivienda y sobre el animal. [Shipstone, M. A., Mason, K. V. The use of Insect Development Inhibitors as an oral medication for the control of the fleas Ctenocephalides felis, Ct. canis in the dog and cat (El uso de inhibidores del desarrollo de insectos como medicación oral para el control de las pulgas Cenocephalides felis y Ct. canis en el perro y en el gato). Abstract— There are two oral Insect Development Inhibitors (IDI) for the control of fleas. Lufenuron is administered once a month at 10 mg × kg^-1 for dogs and 30 mg × kg^-1 for cats. Cyromazine is administered daily at 10 mg kg^-1 in combination with diethylcarbamazine citrate for dogs. Neither compound exerts an effect on the adult flea, but rather causes an interruption in normal chitin production through different specific modes of action. This causes death of the immature, developmental life stages of the flea. Thus, both control the adult flea infestation on the animal via the elimination of the environmental life stages of the flea. There is a lag phase of 6–8 weeks between the initiation of IDI administration and reduction in the number of adult fleas on the treated animals. The lag phase results from the survival of immature fleas that were present in the environment before the onset of IDI treatment; it can be reduced by initiating oral IDI treatment in combination with premise and on-animal insecticide treatments.     

虱螨脲亚致死剂量对棉铃虫生长发育和繁殖力的影响

用虱螨脲亚致死剂量处理棉铃虫1龄幼虫和3龄幼虫,结果表明:虱螨脲具有较强后效性,能降低棉铃虫化蛹率、羽化率、产卵量,提高畸形蛹、畸形蛾比例.1龄幼虫按0.1和0.2 mg/kg一次饲毒后,化蛹率分别为20.00%和15.50%,与对照相比显著降低;处理代雌、雄成虫羽化率分别下降6.50%、9.91%和18.48%、21.76%,雌、雄畸形蛾率分别上升15.61%、12.71%和27.55%、19.50%,产卵量下降34.06%和36.50%.第2、3代与第1代相比,化蛹率、羽化率、产卵量、卵孵化率逐渐有所提高,畸形蛹率、畸形蛾率降低,但与对照仍存在差异,表明虱螨脲对试虫的影响随世代延续而减弱,但至少可持续到第3代,且随用药剂量提高,其影响加大.与1龄幼虫饲毒结果相比,对3龄幼虫的影响程度相对较小,但趋势一致.     

Cross-resistance to dicyclanil in cyromazine-resistant mutants of Drosophila melanogaster and Lucilia cuprina

Cyromazine is an insect growth regulator insecticide with a novel mode of action, mainly used to control dipteran insects. Previously, cyromazine-resistant mutants of the Australian sheep blowfly Lucilia cuprina and the vinegar fly Drosophila melanogaster have been isolated following ethyl methanesulfonate mutagenesis and selection for resistance. Here, we show that these cyromazime-resistant mutants are cross-resistant to dicyclanil, an insect growth regulator compound with a similar chemical structure to cyromazine. Dicyclanil was recently introduced as a control agent of L. cuprina. Cross-resistance to the benzylphenylurea insecticide lufenuron was also assessed. Only one D. melanogaster cyromazine-resistant mutant is cross-resistant to lufenuron.