Browsing by Author "Bergmann, Jan"

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    Chrysanthemyl 2-acetoxy-3-methylbutanoate: the sex pheromone of the citrophilous mealybug, Pseudococcus calceolariae
    (PERGAMON-ELSEVIER SCIENCE LTD, 2010) El Sayed, Ashraf M.; Unelius, C. Rikard; Twidle, Andrew; Mitchell, Vanessa; Manning, Lee Anne; Cole, Lyn; Suckling, David M.; Fernanda Flores, M.; Zaviezo, Tania; Bergmann, Jan
    Headspace volatiles collected from virgin females of the citrophilous mealybug, Pseudococcus calceolariae, contain three Compounds not present in the headspace of control samples. The main female-specific compound is identified as[2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-acetoxy-3-methylbutanoate (chrysanthemyl 2-acetoxy-3-methylbutanoate). The other two compounds are identified as [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methanol (chrysanthemol) and [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-hydroxy-3-methylbutanoate (chrysanthemyl 2-hydroxy-3-methylbutanoate). Traps baited with 100 mu g and 1000 mu g of chrysanthemyl 2-acetoxy-3-methylbutanoate captured 4- and 20-fold more males than traps baited with virgin females. (C) 2009 Elsevier Ltd. All rights reserved.
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    Development of Monitoring and Mating Disruption against the Chilean Leafroller Proeulia auraria (Lepidoptera: Tortricidae) in Orchards
    (2021) Fernanda Flores, M.; Bergmann, Jan; Ballesteros, Carolina; Arraztio, Diego; Curkovic, Tomislav
    Simple Summary Proeulia auraria is a native and growing pest insect in fruit orchards in Chile, which calls for environmentally friendly management methods. Using synthetic pheromone compounds, we conducted field trials to optimize the septa load for monitoring adult moths. Using the optimized blend we studied the phenology of males in vineyards, apples, and blueberries, finding two large flight cycles lasting from September to May. Afterward, based on field trials, we concluded that 250 point sources loaded with a total of 78 g/ha of the pheromone blend, provided high disruption of male-female encounters for mating in all crops tested for at least 5 months. We concluded that mating disruption is feasible for P. auraria, needing now the development of a commercial product and of protocols to control this pest. The leafroller Proeulia auraria (Clarke) (Lepidoptera: Tortricidae) is a native, polyphagous, and growing pest of several fruit crops in Chile; it also has quarantine importance to several markets, thus tools for management are needed. Using synthetic pheromone compounds, we conducted field trials to optimize the blend for monitoring, and to determine the activity period of rubber septa aged under field conditions. We concluded that septa loaded with 200 mu g of E11-14:OAc + 60 mu g E11-14:OH allowed for efficient trap captures for up to 10 weeks. Using this blend, we studied the phenology of adult males in vineyards, apple, and blueberry orchards, identifying two long flight cycles per season, lasting from September to May and suggesting 2-3 generations during the season. No or low adult activity was observed during January and between late May and late August. Furthermore, mating disruption (MD) field trials showed that application of 250 pheromone point sources using the dispenser wax matrix SPLAT (Specialized Pheromone and Lure Application Technology, 10.5% pheromone) with a total of 78 g/ha of the blend described above resulted in trap shutdown immediately after application, and mating disruption >99% in all orchards for at least 5 months. We concluded that MD is feasible for P. auraria, needing now the development of a commercial product and the strategy (and protocols) necessary to control this pest in conventional and organic orchards in Chile. As far as we know, this is the first report on MD development against a South American tortricid pest.
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    Influence of different plants substrates on development and reproduction for laboratory rearing of Pseudococcus calceolariae (Maskell) (Hemiptera: Pseudococcidae)
    (2010) Zaviezo, Tania; Cadena, Elizabeth; Fernanda Flores, M.; Bergmann, Jan
    T. Zaviezo, E. Cadena, M. F. Flores, and J. Bergmann. 2010. Influence of different plants substrates on development and reproduction for laboratory rearing of Pseudococcus calceolariae (Maskell) (Hemiptera: Pseudococcidae). Cien. Inv. Agr. 37(3): 31-37. The citrophilus mealybug, Pseudococcus calceolariae, is a polyphagous pest that has a major impact on fruit crops in central Chile, and is of quarantine importance for many markets. To study many control alternatives, it is important to develop efficient rearing protocols. The objective of this work was to determine mealybug development on three different plant substrates: sprouted potatoes, lemon fruits and Butternut squash. Insects were inoculated on the substrates, maintained at 25 degrees C and in total darkness until completing their development. Every one to 4 days, advancement on the development was checked by counting the exuvia. Mean developmental time for each stage, adult longevity, fecundity and fertility were determined. Preimaginal developmental time was similar for females and males, but it differed among plant substrates. For females, preimaginal development was about nine days shorter on potatoes, as compared to butternut squash or lemons, and for males about 12 days longer in squash than on the other two substrates. The preoviposition period was significantly longer in squash and consequently, a longer generational time resulted. Female adult longevity was similar in all substrates, around 31 days, and for males it was 6 days in potatoes and lemons and 4 days on squash. Female fecundity was similar in potatoes and squash, and lower on lemons. Egg fertility was significantly higher on potatoes. Parthenogenetic reproduction was not observed. Therefore, the three substrates were adequate for rearing P calceolariae, but the shortest developmental time and highest fecundity and fertility were obtained on sprouted potatoes.
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    Mode of action, chemistry and defensive efficacy of the osmeterium in the caterpillar Battus polydamas archidamas
    (2023) Palma-Onetto, Valeria; Bergmann, Jan; Gonzalez-Teuber, Marcia
    Chemical secretions are one of the main defensive mechanisms in insects. The osmeterium is a unique organ in larvae of Papilionidae (Lepidoptera), which is everted upon disturbance, secreting odoriferous volatiles. Here, using larvae of the specialized butterfly Battus polydamas archidamas (Papilionidae: Troidini), we aimed to understand the mode of action of the osmeterium, the chemical composition and origin of the secretion, as well as its defensive efficiency against a natural predator. We described osmeterium's morphology, ultramorphology, structure, ultrastructure, and chemistry. Additionally, behavioral assays of the osmeterial secretion against a predator were developed. We showed that the osmeterium is composed of tubular arms (made up by epidermal cells) and of two ellipsoid glands, which possess a secretory function. The eversion and retraction of the osmeterium are dependent on the internal pressure generated by the hemolymph, and by longitudinal muscles that connect the abdomen with the apex of the osmeterium. Germacrene A was the main compound present in the secretion. Minor monoterpenes (sabinene and ss-pinene) and sesquiterpenes ((E)-beta-caryophyllene, selina-3,7(11)-diene, and other some unidentified compounds) were also detected. Only sesquiterpenes (with the exception of (E)-beta-caryophyllene) are likely to be synthesized in the osmeterium-associated glands. Furthermore, the osmeterial secretion proved to deter predatory ants. Our results suggest that the osmeterium, besides serving as an aposematic warning for enemies, is an efficient chemical defense, with its own synthesis of irritant volatiles.
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    Searching behavior of cryptolaemus montrouzieri (coleoptera: Coccinellidae) in response to mealybug sex pheromones
    (2018) Urbina, Alvaro; Verdugo, Jaime A.; López, Eugenio; Bergmann, Jan; Zaviezo Palacios, Tania; Flores, María Fernanda