Browsing by Author "Borges, Isabel"
Now showing 1 - 10 of 27
Results Per Page
Sort Options
- Abundance of Epiphyas postvittana (Walker, 1863) in forestry nurseries of São Miguel Island (Azores, Portugal) (Lepidoptera: Tortricidae)Publication . Oliveira, Luísa; Vieira, Virgilio; Soares, António O.; Borges, Isabel; Arruda, Patrícia Melo; Tavares, JoãoEpiphyas postvittana (Walker, 1863) is an invasive polyphagous pest for the Azores and its bioecology and the potential natural enemies were unknown. We evaluated the temporal profile of this species larval abundance and the number of males captured in sex pheromone traps, hypothesizing that both profiles were similar. The study was carried out on seven endemic host plants and one native species grown in two forest nurseries (Furnas and Nordeste) in São Miguel Island over two years from 2018 to 2019. A total of 827 plants attacked by E. postvittana were observed in Furnas nursery (2018: 503, 2019: 324) and 1227 in the Nordeste (2018: 649, 2019: 578), including the presence of 525 larvae distributed by the Furnas (2018: 178, 2019: 79) and from the Nordeste (2018: 131, 2019: 137). In 2019, the average weekly number of males captured in the sex pheromone traps (total 31 weeks) were higher in Furnas (mean ± SE: 9.68 ± 1.982) than in Nordeste (3.33 ± 0.651). In synthesis, (i) the population density varied throughout the year and as a function of the host plant species in production; (ii) the abundance profile of larval and adults suggests has at least three to four generations per year and that adults are active year-round, experiencing some delayed development during the winter; (iii) a low larval density does not represent very serious damage to Azorean endemic plants, but is reflected in the population density of its natural enemies; (iv) some biological control agents are present in the field, parasitizing the larvae (i.e., Braconidae species of Meteorus ictericus (Nees, 1811) and Microgaster opheltes Nixon, 1968); (v) finally, the knowledge of the population dynamics and its natural enemies needs further and long-term study.
- Abundance of Tuta absoluta (Meyrick, 1917) and its natural enemies on tomato crops in greenhouses of different production modes (Azores, Portugal) (Lepidoptera: Gelechiidae)Publication . Oliveira, Luísa; Borges, Isabel; Silva, Dário; Durão, Ana C.; Soares, António O.Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is a major pest of tomato (Solanum lycopersicum L.) crops produced in the Azorean greenhouses. Despite the major concerns, no systematic study is available to describe population dynamics of T. absoluta and its natural enemies. The objective of this study was to compare the abundance of the pest (eggs and larvae) and its native natural enemies, in greenhouses of tomato crops produced under different production modes (biological, traditional and intensive). A sampling program was carried out during 2020-2021 and two production seasons of spring-summer and fall-winter. The abundance of eggs and larvae of T. absoluta were higher in tomato crops in intensive production and lower in biological production mode. Infestations by eggs and larvae were higher in spring-summer seasons. The natural enemies recorded were Macrolophus pygmaeus (Rambur, 1839) (Hemiptera: Miridae), Dicyphus cerastii Wagner, 1951 (Hemiptera: Miridae) and Trichogramma achaeae Nagaraja & Nagarkatti, 1960 (Hymenoptera: Trichogrammatidae). The abundance of natural enemies were very low and, virtually, do not occur during the fall-winter seasons. We found no significant difference between the abundance of M. pygmaeus amongst tomato crops from different production mode but D. cerastii was more abundant on greenhouses of biological production mode. Parasitism rate by T. achaeae does not differ between production modes and crop seasons. Considering the major concerns of the growers by the infestation levels of their crops, together with low abundance of native natural enemies, we suggest the use of biological production mode or an inoculative or augmentative strategy to control the pest in intensive and traditional productions modes.
- An annotated checklist of ladybeetle species (Coleoptera, Coccinellidae) of Portugal, including the Azores and Madeira ArchipelagosPublication . Soares, António O.; Calado, Hugo Renato; Franco, José Carlos; Aguiar, António Franquinho; Andrade, Miguel M.; Zina, Vera; Ameixa, Olga M. C. C.; Borges, Isabel; Magro, AlexandraA comprehensive annotated checklist of the ladybeetle species of Portugal, including the Azores and Madeira archipelagos, is presented. The Coccinellidae fauna comprises a total of 101 species: 83 from the Mainland, 39 from Madeira, and 32 from the Azores. The listed species are distributed among 2 sub-families and 13 tribes: within the subfamily Microweiseinae, Madeirodulini (1 species), Serangiini (2 species), and within the subfamily Coccinellinae, Azyini (1 species), Chilocorini (4 species), Coccidulini (7 species), Coccinellini (30 species), Epilachnini (4 species), Hyperaspidini (7 species), Noviini (2 species), Platynaspini (1 species), Scymnini (37 species), Stethorini (3 species), and Sticholotidini (2 species). The Portuguese fauna comprises 10 exotic species: 5 present in the Mainland, 7 in Madeira, and 6 in the Azores. Harmonia axyridis (Pallas, 1773) from Madeira, Propylea quatuordecimpunctata (Linnaeus, 1758) from the Azores, Delphastus catalinae (Horn, 1895) from the Azores and Madeira, Nephus (Geminosipho) reunioni (Fürsch, 1974) and Nephus (Nephus) voeltzkowi Weise, 1910 from Madeira and Microserangium sp. from the Mainland, are reported for the first time. Some species are considered doubtful records, as explained in the text. These results were obtained by compiling information on the available literature regarding ladybeetle species on the Portuguese mainland and insular territories, and original data.
- Can the ladybird predator Scymnus nubilus contribute to control of the aphid Aphis frangulae, a pest threatening the Macaronesia endemic Frangula azorica?Publication . Borges, Isabel; Arruda, Patrícia Melo; Meseguer, Roberto; Vieira, Virgilio; Pons-Solé, Gemma; Soares, António O.Aphis frangulae (Hemiptera: Aphididae) is a major pest of the laurel forest endemic Frangula azorica (Rosales: Rhamnaceae) produced in nursery conditions by the Forestry Services of the Azores (Portugal). The suitability of A. frangulae for the development and reproduction of a potential biological control agent, Scymnus nubilus (Coleoptera: Coccinellidae), was assessed under laboratory conditions (25 ± 1 °C, 75 ± 5% RH, 16:8 L:D photoperiod). The predation potential of S. nubilus was also assessed. Scymnus nubilus 4th instar larvae and pupae successfully completed development in 9.0 ± 0.2 days. The 4th instar larvae ate 15.1 aphids per day, corresponding to 1.52 mg of biomass ingested. On A. frangulae, S. nubilus females took 5.5 ± 0.3 days to start oviposition and an average of 135 ± 12 eggs were laid per female over the first 15 days of oviposition. Field tests showed that S. nubilus 4th instar larvae were more efficient in controlling the pest in closed systems (isolated aphid colonies) and the effect was more pronounced at high predator densities within three days. In open systems, the aphid natural control was higher than initially expected. This work highlights the role of the large aphidophagous guild present in forestry nurseries. The results of this study show that A. frangulae is an essential prey species for S. nubilus and therefore the predator can be used in pest management programs against this pest. However, further studies focusing on different biological control tactics (inundative or inoculative) are required to assess more accurately the effectiveness of S. nubilus as a biological control agent against A. frangulae.
- Contrasting Phenotypic Variability of Life-History Traits of Two Feral Populations of Macrolophus pygmaeus (Hemiptera: Miridae) under Two Alternative DietsPublication . Borges, Isabel; Oliveira, Luísa; Durão, Ana C.; Arruda, Patrícia Melo; Figueiredo, Elisabete; Franco, José Carlos; Lucas, Éric; Soares, António O.Tuta absoluta is a major pest attacking tomato crops. This invasive species emerged in Europe (Spain) in 2006, and 3 years later it spread to Portugal. In 2009/2010, it was recorded for the first time in the Azores archipelago. Macrolophus pygmaeus is a predator widely used as biological control agent against the tomato leaf miner. This study contrasted the life-history traits and population growth parameters of two feral populations of M. pygmaeus, one from Portugal mainland and one from the Azores archipelago. The predators were tested on single prey diet, either of Ephestia kuehniella eggs, a factitious prey used for mass rearing of mirids, or T. absoluta eggs. We predicted that populations would express differences in its phenotypic characteristics, with the Azorean population displaying low performance due to likely low genetic diversity, as expected for insular populations. Our results revealed the inexistence of phenotypic differences in several life history traits, such as immature developmental time, female longevity, males’ body weight and sex ratio. Contrary to our predictions, traits with direct impact on fitness, such as lifetime fertility (95.78 ± 14.23 vs. 61.38 ± 13.52 nymphs), explain better performances for the population of the Azores. Azorean M. pygmaeus females were larger, matured earlier and reproduced at a higher rate for longer periods, than mainland females. Therefore, population growth parameters show a positive advantage for the population of the Azores, fed on T. absoluta (time required for doubling the population Azores, Ek: 8.42 ± 0.50, Ta: 5.76 ± 0.31 and mainland, Ek: 10.88 ± 1.94, Ta: 12.07 ± 3.15). Biological performance of M. pygmaeus was similar when fed with T. absoluta or E. kuehniella that could be beneficial both to optimize mass production of the predator and biological control of the pest. Our results are discussed as well in a fundamental perspective, seeking if differences in biological performance can be explained by lower genetic diversity driven by geographic isolation.
- Costs and Benefits of Wax Production in the Larvae of the Ladybeetle Scymnus nubilusPublication . Pacheco, Paulo A. B.; Borges, Isabel; Branco, Beatriz; Lucas, Éric; Soares, António O.BACKGROUND: Larvae of the minute aphidophagous Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) are common predators in apple orchards, covered by a wax layer that might act as a defense mechanism against natural enemies. However, the costs and benefits of protection conferred by wax remain to be assessed. We tested the following hypothesis: there is a trade-off in wax producing ladybeetles between the protection conferred by wax cover and the physiological or behavioral costs associated with its production. We predict that: (1) wax production is an efficient defensive mechanism (against intraguild predation), (2) wax production is associated with detrimental physiological (growth, reproduction) or behavioral effects (behavioral compensation: increased biomass consumption). RESULTS: Tests were carried out in the laboratory with wax and waxless larvae of S. nubilus, with and without lacewing larvae of Chrysoperla agilis (Neuroptera: Chrysopidae) being used as a potential intraguild predator of the coccinellid. Waxless individuals were more susceptible to intraguild predation by lacewing larvae. Adults originating from waxless larvae were lighter than the ones originating from wax larvae, suggesting a metabolic cost resulting from a constant need of wax production. Body-weight gain and conversion efficiency were lower in waxless larvae. Biomass consumption was similar, showing that waxless larvae did not compensate for the physiological cost by eating more aphid biomass. CONCLUSION: The results indicate the potential existence of a trade-off between growth and protection associated with wax production.
- Diversity of Lepidoptera (Insecta) recorded in a forest nursery of Nordeste County on São Miguel Island (Azores)Publication . Vieira, Virgilio; Oliveira, Luísa; Soares, António O.; Borges, Paulo A. V.; Borges, Isabel; Tavares, JoãoBACKGROUND: The diversity of moth species (Insecta, Lepidoptera) recorded in the forest nursery of Nordeste County on São Miguel Island (Azores) is given. Adults were sampled between March and December 2019 using three methods: (i) light trap to catch Noctuidae species, (ii) open-sided delta trap baited with a synthetic female sex pheromone lure to attract Epiphyas postvittana (Walker) males and (iii) entomological net to collect microlepidopteran moths. This contribution focuses mainly on the diversity of moths present in one forest nursery of Nordeste County of São Miguel Island (Azores), especially on the species associated with endemic and native plant species. It also contributes to better plan strategies for integrated protection and conservation measures, since nurseries host a great diversity of plants from the Laurel Forest, which may attract many lepidopteran species. NEW INFORMATION: A total of 10160 adults belonging to 33 lepidopteran species were recorded and listed by families, including: Argyresthiidae, one species (3%), Crambidae, four species (12%), Erebidae, one species (3%), Geometridae, five species (15%), Noctuidae, 18 species (55%), Sphingidae, one species (3%), Tineidae, one species (3%) and Tortricidae, two species (6%). The families Noctuidae, Geometridae and Crambidae were the most diverse. Those with the highest abundance of adults were the Noctuidae family, followed by the Geometridae, Crambidae, Tortricidae and Tineidae. The number of caught adults was consistently higher during spring and summer, decreasing sharply in late autumn. For 13 species caught in the light trap, the adult sex ratio was favourable to females. An analysis of the colonisation status, feeding and primary hosts of these endemic, native or exotic moth species contributes to our understanding of the factors that may lead to their establishment in Laurel Forest environments and to what extent there is a need to monitor and control them mainly with biological control agents.
- Diversity of Lepidoptera recorded in a forest nursery of Nordeste county on São Miguel Island (Azores)Publication . Vieira, Virgilio; Oliveira, Luísa; Soares, António O.; Borges, Paulo A. V.; Borges, Isabel; Tavares, JoãoThe diversity of moth species (Insecta, Lepidoptera) recorded in the forest nursery of Nordeste county on São Miguel island (Azores) is given. Adults were sampled between March and December 2019 using three methods: (i) light trap to caught Noctuidae species, (ii) open-sided delta trap baited with a synthetic female sex pheromone lure to attract Epiphyas postvittana males and (iii) entomological net to identify microlepidopteran moths. A total of 10160 adults belonging to 33 lepidopteran species were recorded and listed by families, including: Argyresthiidae 1 (3%), Crambidae 4 (12%), Erebidae 1 (3%), Geometridae 5 (15%), Noctuidae 18 (55%), Sphingidae 1 (3%), Tineidae 1 (3%), and Tortricidae 2 (6%). The families Noctuidae, Geometridae and Crambidae were the most diverse. Those with the highest abundance of adults was the Noctuidae family followed by the Crambidae, Trotricidae and Tineidae. The number of caught adults was consistently higher during spring and summer, decreasing sharply in late fall. For 14 species caught in the light trap the adult sex ratio was favorable to females, except for Xestia c-nigrum which was favorable to males. An analysis of the colonization status, feeding and primary hosts of these endemic, native or exotic moth species suggests that plants reared in forest nurseries, being attacked by such insects, facilitates our understanding of the diversity of lepidopterans that establish in Laurel Forest environments and to what extent there is a need to monitor and control them mainly with biological control agents.
- Economic and financial model to the mass‐rearing of Macrolophus pygmaeus (Rambur) (Heteroptera: Miridae), a biological control agent against the tomato moth Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in protected culturePublication . Dutra, Tiago M.; Batista, Maria Da Graça; Teixeira, João; Todorova, Silvia; Oliveira, Luísa; Tavares, João; Borges, Isabel; Soares, António O.ABSTRACT: BACKGROUND - Tuta absoluta (Meyrick) is a major pest of tomato produced in glasshouses and open field, causing severe damages to crops, reducing the quality of tomato fruits. The current maintenance of the pest populations below the economic threshold is not achieved by natural and classical control, thus requiring the continuous application of biological control agents (BCAs), under an augmentative or inoculative approach. The present study aims to develop an economic and financial model to evaluate the commercial viability of a continuous mass production of Macrolophus pygmaeus (Rambur), a BCA commonly used against the tomato moth, Tuta absoluta, in protected culture. The estimations for our model were based on two approaches: the farm-level impact analysis and the benefit–cost analysis. RESULTS - The results of the farm-level analysis show that the adoption of a more sustainable biological control approach is profitable for farmers and the benefit–cost analysis provides evidence that the investment on a new factory dedicated to the mass rearing of M. pygmaeus to control tomato moth populations generates a positive net present value (NPV) of 7.2 million euros, corresponding to an internal rate of return (IRR) of 28.4% per year. CONCLUSION - Our results are in line with (i) the more recent European Commission proposals for a new Regulation on sustainable use of plant protection products, which includes the reduction of 50% the use and risk of chemical pesticides by 2030 and (ii) most of the existing literature which conclude that new projects on BCA production are worth investments.
- Eden Arthropod Azores DatabasePublication . Marcelino, Jose; Borges, Paulo A. V.; Borges, Isabel; Soares, António O.This study intended to contribute to the current international directives concerning biodiversity, aiming to document and safeguard biological resources of the globe. Our objective was to present the most widely distributed and diverse taxa recorded during the sampling phase of the EDEN project (2008-2014), specifically all arthropod fauna, at all strata, within eight representative habitats of five islands of the Azores archipelago (Santa Maria, São Miguel, Terceira, Flores and Pico)
- «
- 1 (current)
- 2
- 3
- »