DSpace Angular :: Browsing by Author "Zaviezo, Tania "

Browsing by Author "Zaviezo, Tania "

Now showing 1 - 20 of 20

A new species of Pseudococcus (Hemiptera: Pseudococcidae) belonging to the "Pseudococcus maritimus" complex from Chile: molecular and morphological description
(MAGNOLIA PRESS, 2011) Correa, Margarita; Aguirre, Carlos; Germain, Jean Francois; Hinrichsen, Patricio; Zaviezo, Tania; Malausa, Thibaut; Prado, Ernesto
A new species of mealybug from Chile, Pseudococcus meridionalis Prado sp. n., is described and illustrated based on the morphological and molecular characterization of adult females. This species belongs to the "Pseudococcus maritimus" complex and displays a wide host plant range, including Japanese pear, persimmon, pomegranate, pear and grape.
Apparent niche differences between native and exotic lady beetles
(2023) Croy, Jordan R.; Zaviezo, Tania; Crossley, Michael S.; Smith, Olivia M.; Snyder, William E.; Grez, Audrey A.
Generalist predators can enhance biological control by filling unique niches and complementing other natural enemies, or disrupt it by preying upon other predators and parasitoids, complicating their net value for biological control. We searched for evidence of complementarity and/or interference between native (primarily Eriopis chilensis and E. eschscholtzi) and exotic (primarily Hippodamia variegata and Harmonia axyridis) lady beetles attacking aphids in alfalfa (Medicago sativa) fields near Santiago, Chile. Across 60 fields and three growing seasons, exotic lady beetle adults and larvae reached peak abundance relatively earlier in the growing season than the natives. Furthermore, exotic lady beetle peaks aligned more closely with aphid peak abundance than did native lady beetle peaks. Abundances of native lady beetle adults and larvae were weakly positively correlated with those of exotics, and peak aphid densities were generally lowest in fields where native and non-native lady beetle adults were similarly abundant. Therefore, we did not see evidence of strong interference between exotics and natives. Natural-agricultural habitat edges reduced native, but not exotic, larval lady beetle lag behind aphid peaks and was associated with greater lady beetle and lower aphid densities. Moreover, farms embedded in landscapes with greater natural habitat cover supported more exotic, but not native, lady beetles, and increased the lag between larval lady beetles and aphids for natives but not exotics. These findings support the idea that farms embedded within mosaics of natural and agricultural habitats may provide greater interaction potential between native lady beetles and aphid pests on farms as they move across the landscape, leading to greater top -down control. In contrast, exotic lady beetle lags were unaffected by landscape composition or configuration, but their greater densities in farms surrounded by more natural habitats might reflect a 'concentration effect' whereby exotic lady beetle abundance becomes concentrated in the agricultural habitats that they prefer. Our findings suggest that some lady beetles introduced for biocontrol may be better adapted to intensively managed habitats than natives, possibly leading to spatiotemporal complementarity between native and exotic lady beetles.
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.
Development of microsatellite markers and detection of genetic variation between Goniozus wasp populations
(2014) Khidr, Sahand K.; Hardy, Ian C. W.; Zaviezo, Tania; Mayes, Sean
Molecular genetic markers reveal differences between genotypes according to the presence of alleles (the same or different) at target loci. Microsatellite markers are especially useful co-dominant markers that have been used in a wide range of studies to elucidate the population structure and dynamics of a range of organisms, including agriculturally beneficial insects such as parasitic wasps (parasitoids). In the present study, twelve primer pairs were designed for the south Asian, Goniozus nephantidis (Muesebeck) (Hymenoptera: Bethylidae), and 24 for its New World congener, Goniozus legneri Gordh, parasitoids of the larvae of the lepidopteran coconut pest Opisina arenosella Walker (Lepidoptera: Crytophasidae) and other lepidopteran pests, respectively, in order to investigate polymorphism within and between populations. The wasps fingerprinted were a total of 85 G. nephantidis and G. legneri, including individuals belonging to three putatively different strains of G. legneri. Annealing gradient tests (50-65 degrees C) were conducted to study the quality of the PCR amplification across an annealing temperature gradient using a mixed genotype DNA template from each species separately. Seven primer pairs, which amplified clear products of approximately the expected size of G. nephantidis and 18 of G. legneri, were then selected for capillary analysis for fragment size determination on a Beckmann CEQ 8000. Neither G. nephantidis nor G. legneri were polymorphic within populations. However, there were six primer pairs that did show polymorphism between G. legneri populations that originated from different geographical areas within South America (Uruguay and Chile). Furthermore, one primer pair revealed diversity between the two strains collected within Chile. One of the markers was subsequently used to provide unbiased assessment of primary sex ratio in G. legneri.
Diversity and foraging activity of bats in cultivated and uncultivated areas in agroecosystems of a Mediterranean-climate hotspot
(2019) Muñoz, Alejandra E. ; Ossa, Gonzalo ; Zaviezo, Tania ; Bonacic, Cristián
Bats are one of the least-studied vertebrate groups in Chile. We sampled six fruit farms in the Mediterranean-climate zone and three in a semiarid zone during 2015 and 2016, respectively. We assessed if activity (passes) and foraging (feeding buzzes) of bat species differed between cultivated and uncultivated intra-farm habitats. We found six bat species, all threatened and insectivorous. Tadarida brasiliensis was the most frequently recorded species. We found more activity and foraging in uncultivated than cultivated habitats in total, although the opposite trend was observed during springtime in semiarid region. More than a third of the bat passes were feeding buzzes in both habitats, suggesting the potential service to agriculture. Further investigation is needed to promote conservation of bats and their integration as biocontrols in agroecosystems in Chile.
Ecoinformatics for Integrated Pest Management: Expanding the Applied Insect Ecologist's Tool-Kit
(ENTOMOLOGICAL SOC AMER, 2011) Rosenheim, Jay A.; Parsa, Soroush; Forbes, Andrew A.; Krimmel, William A.; Law, Yao Hua; Segoli, Michal; Segoli, Moran; Sivakoff, Frances S.; Zaviezo, Tania; Gross, Kevin
Experimentation has been the cornerstone of much of integrated pest management (IPM) research. Here, we aim to open a discussion on the possible merits of expanding the use of observational studies, and in particular the use of data from farmers or private pest management consultants in "ecoinformatics" studies, as tools that might complement traditional, experimental research. The manifold advantages of experimentation are widely appreciated: experiments provide definitive inferences regarding causal relationships between key variables, can produce uniform and high-quality data sets, and are highly flexible in the treatments that can be evaluated. Perhaps less widely considered, however, are the possible disadvantages of experimental research. Using the yield-impact study to focus the discussion, we address some reasons why observational or ecoinformatics approaches might be attractive as complements to experimentation. A survey of the literature suggests that many contemporary yield-impact studies lack sufficient statistical power to resolve the small, but economically important, effects on crop yield that shape pest management decision-making by farmers. Ecoinformatics-based data sets can be substantially larger than experimental data sets and therefore hold out the promise of enhanced power. Ecoinformatics approaches also address problems at the spatial and temporal scales at which farming is conducted, can achieve higher levels of "external validity," and can allow researchers to efficiently screen many variables during the initial, exploratory phases of research projects. Experimental, observational, and ecoinformatics-based approaches may, if used together, provide more efficient solutions to problems in pest management than can any single approach, used in isolation.
Effects of habitat loss and fragmentation on the abundance and species richness of aphidophagous beetles and aphids in experimental alfalfa landscapes
(CZECH ACAD SCI, INST ENTOMOLOGY, 2008) Grez, Audrey A.; Zaviezo, Tania; Diaz, Sandra; Camousseigt, Bernardino; Cortés Hinojosa, Galaxia Andrea
In agro-ecosystems, habitat loss and fragmentation may alter the assemblage of aphidophagous insects, Such as foliar-foraging (coccinellids) and ground-foraging predators (carabids), potentially affecting intraguild interactions. We evaluated how habitat loss (0, 55 and 84%), fragmentation (1, 4 and 16 fragments) and their combination affected the abundance and species richness of coccinellids and carabids, and aphid abundance, both in the short-term (summer: December to February) and over a longer time span (autumn: March to May), when different demographic mechanisms may participate. We created four types of 30 x 30 in patches (landscapes) in which alfalfa was grown: Control (IF - 0%, 30 x 30 ill patch of alfalfa with no fragmentation or habitat loss), 4F - 55% (4 alfalfa fragments, with 55% total habitat loss), 4F - 84% (4 alfalfa fragments, with 84% total habitat loss), and 16F - 84% (16 alfalfa fragments, with 84% total habitat loss). Each landscape type was replicated five times. Insects were sampled by sweep-netting and pitfall traps, from December (summer) to May (autumn). Total abundance and species richness of carabids, in the short-term, was highest in the 1 6F - 84% landscapes. Total abundance of adult coccinellids was similar among landscapes, but at the species level Hyperaspis sphaeridioides, in the short-term, and Adalia bipunctata, in the long-term, had their highest densities in fragments within landscapes with high habitat loss (84%), independently of habitat fragmentation. Species richness in the long-term was higher in the landscapes with 84% habitat loss. Among aphids, in the long term Aphis craccivora was less abundant in landscapes with high habitat loss and fragmentation (16-84%), while Therioaphis trifolii showed the opposite trend. These results suggest that habitat loss and fragmentation may increase the density and diversity of aphidophagous insects, while their effects oil aphids are more variable.
Effects of habitat loss, habitat fragmentation, and isolation on the density, species richness, and distribution of ladybeetles in manipulated alfalfa landscapes
(WILEY, 2006) Zaviezo, Tania; Grez, Audrey A.; Estades, Cristian F.; Perez, Astrid
1. Habitat loss and fragmentation are the main causes of changes in the distribution and abundance of organisms, and are usually considered to negatively affect the abundance and species richness of organisms in a landscape. Nevertheless, habitat loss and fragmentation have often been confused, and the reported negative effects may only be the result of habitat loss alone, with habitat fragmentation having nil or even positive effects on abundance and species richness.
Harmonia axyridis in Chile: a new threat
(2010) Grez, Audrey; Zaviezo, Tania; Gonzalez, Guillermo; Rothman, Sergio
A. Grez, T. Zaviezo, G. Gonzalez, and S. Rothmann. 2010. Harmonia axyridis in Chile: a new threat. Cien. Inv. Agr. 37(3): 145-149. In this work, we document the presence of Harmonia axyridis in Chile, an invasive coccinellid species that has had negative effects in other regions of the world, such as: impacts on non-target arthropods, invasions of houses and fruit damage. This species has been found in the last three years in the Metropolitan and Valparaiso regions, in crops, pine plantations and inside houses. We warn about the consequences of the introduction of this species to Chile and claim to take actions to avoid its spread in the country.
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.
Influence of different plants substrates on development and reproduction for laboratory rearing of Pseudococcus calceolariae (Maskell) (Hemiptera: Pseudococcidae).
(2010) Zaviezo, Tania; Cadena, Elizabeth; Flores, M. Fernanda; Bergmann, Jan
Influence of mealybug (Pseudococcus spp.)-infested bunches on wine quality in Carmenere and Chardonnay grapes
(WILEY, 2012) Bordeu, Edmundo; Troncoso, Diego O.; Zaviezo, Tania
This study evaluated the effects of processing grape with different proportions of mealybug-infested bunches in wine quality in cultivars Chardonnay and Carmenere. No differences in chemical composition of musts were found. Basic chemical composition for white and red wines was similar. In both cultivars total polyphenols decreased as the proportion of infested bunches increased, from 266 to 239 (mg L-1 gallic acid) in Chardonnay and 2124 to 1820 in Carmenere. The same trend was observed in Carmenere for anthocyanins and tannins, by spectrophotometry and high performance liquid chromatography. Dimethyl amino cinnamaldehyde index in Carmenere went from 28.6 in wines 100% healthy bunches to 22.0 for the 100% infested, and tannin galoilation went from 3.85 to 0.74%. Sensory analysis showed that wines with larger proportion of infested grapes were associated with negative descriptors and lower quality. These results show that mealybugs have the potential of negatively impacting wine quality and this deserves further attention.
Landscape simplification, urbanization, biological invasions, and climate change: a review of the major threats to native coccinellids in Central Chile
(WILEY, 2024) Grez, Audrey; Zaviezo, Tania
Coccinellids (Coleoptera) are important natural enemies of pests in agroecosystems. However, worldwide, native species face several threats, including landscape simplification, biological invasions, and climate change. In Central Chile, one of the global biodiversity hotspots, coccinellid communities are very diverse and are composed mostly of native species, which are most common in less disturbed habitats. In alfalfa fields, native coccinellids play a crucial role in the biological control of aphids, even when they are less abundant than exotics. However, in the last 2 decades, native species in this crop have declined in abundance and diversity. Our long-lasting field and laboratory studies have shown that this decline is associated with: (1) the invasion of Harmonia axyridis (Pallas), which has superior competitive abilities and escapes more from parasitism; (2) the simplification of agricultural landscapes, loss of natural habitats, and urbanization; and (3) increasing environmental temperatures and decreasing precipitation. The decline in native coccinellid populations has resulted in a loss of taxonomic and functional diversity of assemblages, which may jeopardize biological control. Alfalfa fields and natural and semi-natural habitats may offer an opportunity for the conservation of native coccinellids in agricultural landscapes. Such conservation might be achieved with better management of alfalfa fields and surrounding areas., Worldwide, native coccinellids (Coleoptera) face multiple threats. In Central Chile, coccinellid communities are diverse, with mostly native species. However, they have declined because of (1) invasion of Harmonia axyridis, (2) simplification of agricultural landscapes, natural habitats loss, and urbanization, and (3) increasing temperatures and decreasing precipitation. The decline in native coccinellids has resulted in lower taxonomic and functional diversity of assemblages, jeopardizing biological control. Alfalfa fields and natural and semi-natural habitats may offer an opportunity for their conservation in agricultural landscapes.image
Migration of coccinellids to alfalfa fields with varying adjacent vegetation in Central Chile
(2010) Grez, Audrey A.; Torres, Constanza; Zaviezo, Tania; Lavandero, Blas; Ramirez, Marcelo
A. A. Grez, C. Torres, T. Zaviezo, B. Lavandero, and M. Ramirez. Migration of coccinellids to alfalfa fields with varying adjacent vegetation in Central Chile. 2010. Cien. Inv. Agr. 37(2): 111-121. Permanent and permeable edges, where natural enemies can feed, overwinter or easily cross over, should enhance the early arrival of these predators to crops. We evaluated the abundance and species richness of coccinellids migrating to alfalfa fields adjacent to Eucalyptus, a mix of false acacia, blackberries and poplar (F-B-P), vineyards, corn and annual vegetables. From September 2007 to May 2008, we captured coccinellids in three sticky traps (2.64 m(2)) placed at the borders between alfalfa fields and adjacent vegetation. We also estimated the abundance of aphid populations in the alfalfa fields, by counting the number of individuals per alfalfa stem in spring, summer and autumn. We collected 90,396 coccinellids from 14 species. Neither total abundance nor species richness of coccinellids was significantly affected by adjacent vegetation, but Adalia deficiens, Psyllobora picta and Cycloneda sanguinea were more abundant in alfalfa adjacent to Eucalyptus and F-B-P, meanwhile Olla v-nigrum next to annual crops and Hyperaspis sphaeridioides next to vineyards. Edge height and orientation explained 94% of the variance in species abundance. Particularly, P picta and O. v-nigrum were positively and negatively influenced by border height, respectively. Hyperaspis sphaeridioides was negatively affected by northern exposure and none of the species was affected by edge permeability. Aphids were less abundant in alfalfa fields adjacent to F-B-P, especially in spring. These results show that most species of coccinellids were not affected by the composition of crop edges, although tall permanent edges may enhance the arrival of particular coccinellid species to alfalfa fields.
Migration of coccinellids to alfalfa fields with varying adjacent vegetation in Central Chile.
(2010) Grez, Audrey A.; Torres, Constanza; Zaviezo, Tania; Lavandero, Blas; Ramírez, Marcelo
Native flower strips increase visitation by non-bee insects to avocado flowers and promote yield
(2021) Muñoz, Alejandra E. ; Plantegenest, Manuel ; Amouroux, Paul ; Zaviezo, Tania
Pollination is an essential ecosystem service for pollinator-dependent crops and plant communities. Apis mellifera L. is by far the most commonly used species to obtain this service in agriculture. However, there is growing evidence of the importance for crop yields of the service provided by wild bees and non-bee insect pollinators. Establishing flower resources in agricultural landscapes is a management practice that can increase insect pollinator populations and improve crop yields. We established perennial native flower strips (NFS) in four avocado orchards in central Chile during autumn 2017. We monitored flower visitors and counted newly formed fruits in avocados near and far from NFS in spring 2019, to assess flower visitor groups, flower visitation rates and fruit numbers. Only A. mellifera visited avocado flowers within bees, whereas both the managed A. mellifera and wild bees were the main visitors to the NFS. NFS increased visitation rates to adjacent avocado of flies, and with a trend for the sum of all non-managed flower visitors (i.e. excluding A. mellifera). However, there were no differences in the rates of A. mellifera visitation to avocados near and far from NFS. Avocado fruit numbers were higher among avocados near NFS than among those farther away. This difference could be due to better pollination by the increased visits to avocado flowers by flies or other wild insects. Therefore, NFS could contribute to crop fruit number, as well as conservation of native flora, wild bees and non-bee pollinators on fruit farms in the "Central Chile" biodiversity hotspot. (C) 2021 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.
Native flowering shrubs promote beneficial insects in avocado orchards
(2021) Muñoz, Alejandra E. ; Amouroux, Paul ; Zaviezo, Tania
Flower strips can promote and conserve beneficial insects in agroecosystems. Knowing which groups are favoured and which plant traits affect visitation rates by beneficial insects is important for the design of plant strips.
Natural enemy communities of aphids in alfalfa fields assessed through video recordings of sentinel cards in scenarios of contrasting aphid abundance
(2024) Grez, Audrey A.; Zaviezo, Tania; Molina, Gabriela
The first step to better understand the relationship between natural enemy communities and pest control is to know which, when, and how frequently different natural enemies interact with their prey. In alfalfa fields of central Chile, aphids are the most common pests and are consumed by predators such as coccinellids, syrphids, and spiders. In this study, through video recording, we analyzed how natural enemy communities visiting aphid sentinel cards vary between scenarios of low and high abundance of aphids in alfalfa in spring. On 15 occasions, during the day, we monitored the natural enemies visiting cards with sentinel aphids (60 cards per field; total 900) located in fields with high (n = 6) and low (n = 9) aphid abundance. We also analyzed whether the abundance of coccinellid species visiting sentinel cards was related to their abundance in each field. In 750 h of video recording, we found 2749 natural enemies visiting the sentinel cards; 86.2% of them were coccinellids of five species. Total natural enemies and coccinellid visits were three times higher in low than in high aphid abundance scenarios. In contrast, the species richness and diversity of natural enemies and coccinellids visiting cards did not differ between aphid scenarios. The abundance of coccinellids in the field was positively associated with the abundance of coccinellids visiting cards, for the three most abundant species. Our study shows that video recording is useful for identifying changes in the communities of natural enemies of aphids in alfalfa, providing important new insights into trophic interactions in field situations.
Primer registro de Goniozus legneri (Hymenoptera: Bethylidae) para Chile.
(2007) Zaviezo, Tania; Romero, Alda; Castro, David; Wagner, Adrián
The invasive coccinellid Harmonia axyridis (Coleoptera: Coccinellidae) is a less suitable host for parasitism than resident species
(2020) Romero, Violeta; Zaviezo, Tania; Grez, Audrey A.
Harmonia axyridis (Pallas) has invaded most continents in the world, including South America. In Chile, it became invasive after 2010, turning into a dominant species in coccinellid guilds in alfalfa crops, where it coexists with the introduced species Hippodamia variegata (Goeze) and the native species Eriopis chilensis Hofmann, the populations of which declined after the invasion of H. axyridis. One of the mechanisms attributed to the success of invasive species is the enemy release hypothesis (ERH), which predicts that natural enemies will have a lesser impact on the invasive species in the newly invaded areas than on resident species. Dinocampus coccinellae (Hymenoptera: Braconidae) is a cosmopolitan parasitoid of coccinellids, which vary in their suitability to parasitism according to species and location. The present study evaluated whether H. axyridis is a less suitable host than H. variegata and E. chilensis for D. coccinellae by assessing each step in the parasitism process, from oviposition to adult emergence in field and laboratory conditions. In the field, successful parasitism in H. axyridis (7%) was significantly lower than in H. variegata (33%) and E. chilensis (36%). H. axyridis was also the only species in which failed parasitoid larval development was greater than successful parasitism (adult emergence). In the laboratory, D. coccinellae never successfully oviposited in H. axyridis, while it did in the other two species. These results suggest that in Chile, H. axyridis is a less suitable host than the resident species for D. coccinellae. This mechanism, among others, may explain the dominance of this species in this early stage of invasion.

Browsing by Author "Zaviezo, Tania "

Results Per Page

Sort Options