Feeding preference and intraguild interactions between the parasitoid Trichogramma achaeae and the predator Macrolophus pygmaeus, two biological agents of Tuta absoluta

ABSTARCT: Tuta absoluta is an exotic species and a major pest of tomato crops in Europe. Macrolophus pygmaeus and Trichogramma achaeae are two biocontrol agents widely used in integrated pest management programs of the South American tomato pinworm Tuta absoluta. In this study, we evaluated under laboratory conditions the (i) voracity of M. pygmaeus females fed on single diets of Tuta absoluta eggs parasitized or unparasitized by Trichogramma achaeae, (ii) voracity and feeding preference of M. pygmaeus females provided with mixed diets of Tuta absoluta eggs unparasitized and parasitized by Trichogramma achaeae and (iii) effect of competitive and intraguild interactions between M. pygmaeus and Trichogramma achaeae on the number of Tuta absoluta eggs consumed and/or parasitized. Lastly, we assessed under field conditions the effect of interspecific and intraspecific interactions between natural enemies on the number of Tuta absoluta eggs consumed and/or parasitized.info:eu-repo/semantics/publishedVersio

Is there a causal role for homocysteine concentration in blood pressure?:A Mendelian randomization study

Background: An understanding of whether homocysteine is a cause or a marker of increased blood pressure is relevant because blood homocysteine can be effectively lowered by safe and inexpensive interventions (e.g., vitamin B-6, B-9, and B-12 supplementation). Objective: The aim was to assess the causal influence of homocysteine on systolic and diastolic blood pressure (SBP and DBP, respectively) in adults with the use of Mendelian randomization (MR). Design: Data from the 1982 Pelotas Birth Cohort (Brazil) were used. A total of 4297 subjects were evaluated in 2004–2005 (mean age: 22.8 y). The association of homocysteine concentration with SBP and DBP was assessed by conventional ordinary least-squares (OLS) linear regression and 2-stage least-squares (2SLS) regression (MR analysis). The single nucleotide polymorphism (SNP) methylenetetrahydrofolate reductase (MTHFR) C677T (rs1801133) was used as proxy for homocysteine concentration. We also applied MR to data from the International Consortium for Blood Pressure (ICBP) genomewide association studies (>69,000 participants) using rs1801133 and additional homocysteine-associated SNPs as instruments. Results: In OLS regression, a 1-SD unit increase in log homocysteine concentration was associated with an increase of 0.9 (95% CI: 0.4, 1.4) mm Hg in SBP and of 1.0 (95% CI: 0.6, 1.4) mm Hg in DBP. In 2SLS regression, for the same increase in homocysteine, the coefficients were −1.8 mm Hg for SBP (95% CI: −3.9, 0.4 mm Hg; P = 0.01) and 0.1 mm Hg for DBP (95% CI: −1.5, 1.7 mm Hg; P = 0.24). In the MR analysis of ICBP data, homocysteine concentration was not associated with SBP (β = 0.6 mm Hg for each 1-SD unit increase in log homocysteine; 95% CI: −0.8, 1.9 mm Hg) but was positively associated with DBP (β = 1.1 mm Hg; 95% CI: 0.2, 1.9 mm Hg). The association of genetically increased homocysteine with DBP was not consistent across different SNPs. Conclusion: Overall, the present findings do not corroborate the hypothesis that homocysteine has a causal role in blood pressure, especially in SBP

Abundance of Tuta absoluta (Meyrick, 1917) and its natural enemies on tomato crops in greenhouses of different production modes (Azores, Portugal) (Lepidoptera: Gelechiidae)

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.info:eu-repo/semantics/publishedVersio

Abundance of Epiphyas postvittana (Walker, 1863) in forestry nurseries of São Miguel Island (Azores, Portugal) (Lepidoptera: Tortricidae)

Epiphyas 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.This research was support by Oficial Forestry Services from Regional Government of the Azores, through the research project MoCIL "Monitorização e Controlo Integrado de Lepidópteros em Viveiros Florestais (Nordeste e Furnas) na ilha de São Miguel -Açores", in direct collaboration with the Forestry Engineers Carina Nóbrega and Catarina Quintela. Special thanks are due to laboratory technician Manuel Fernando Almeida for their help in the field work.info:eu-repo/semantics/publishedVersio

Diversity of Lepidoptera recorded in a forest nursery of Nordeste county on São Miguel Island (Azores)

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 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.Regional Founds, through Official Forestry Services from Regional Government of the Azores, within the research project MoCIL “Monitorização e Controlo Integrado de Lepidópteros em Viveiros Florestais (Nordeste e Furnas) na ilha de São Miguel - Açores” FCT – Fundação para a Ciência e a Tecnologia, I.P., under the project UIDP/05292/2020 and UIDB/05292/2020. AZORESBIOPORTAL–PORBIOTA (ACORES-01-0145-FEDER-000072) (2019-2022).info:eu-repo/semantics/publishedVersio

Diversity of Lepidoptera (Insecta) recorded in a forest nursery of Nordeste County on São Miguel Island (Azores)

BACKGROUND: 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.This research was supported by the Official Forestry Services from the Regional Government of the Azores, through the research project MoCIL "Monitorizacao e Controlo Integrado de Lepidopteros em Viveiros Florestais (Nordeste e Furnas) na ilha de Sao Miguel - Acores", in direct collaboration with the Forestry Engineers Carina Nobrega and Catarina Quintela, by FCT - Fundacao para a Ciencia e a Tecnologia, I.P., under the project UIDP/05292/2020 and UIDB/05292/2020 and by AZORESBIOPORTAL PORBIOTA (ACORES-01-0145-FEDER-000072) (2019-2022).info:eu-repo/semantics/publishedVersio

Determination of ammonium in marine waters using a gas diffusion multicommuted flow injection system with in-line prevention of metal hydroxides precipitation

A multi-commuted flow system coupled to a gas diffusion device was developed for the spectrophotometric determination of ammonium nitrogen in sea and estuarine waters. The efficiency of complexing agents to prevent precipitation of metallic hydroxides, due to the high pH value of the carrier solution, was studied. Under the optimised conditions, no interference was observed from different expected interfering ions as well as volatile amines. The proposed method provided the determination of NH4 + in concentrations ranging from 50 to 1000 mg L 1, with detection and quantification limits of 18 and 35 mg L 1, respectively. A determination rate of 20 h 1 was achieved, with good repeatability for 10 consecutive injections of sea and estuarine samples (relative standard deviations lower than 2.0%). Accuracy of the methodology was assessed through recovery assays in 10 samples and also by analysis of certified reference material

Contrasting Phenotypic Variability of Life-History Traits of Two Feral Populations of Macrolophus pygmaeus (Hemiptera: Miridae) under Two Alternative Diets

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.FUNDING: This study was financed by FEDER in 85% and by Azorean Public funds by 15% through Operational Program Azores 2020, under the project ECO2–TUTA (ACORES-01-0145-FEDER-000081). L.O. was funded by Portuguese national funds FCT under the project UIDP/05292/2020 and UIDB/05292/2020. E.F. was funded by Portuguese national funds FCT Umbert-ECO PTDC/ASPPLA/29110/2017. J.C.F. and E.F. received backing from Forest Research Centre (CEF) and Linking Landscape, Environment, Agriculture and Food (LEAF) research center, respectively, research units funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal (UIDB/00239/2020 and UIDB/04129/2020, respectively), and both researchers from the Laboratory for Sustainable Land Use and Ecosystem Services–TERRA (LA/P/0092/2020).info:eu-repo/semantics/publishedVersio

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 culture

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.info:eu-repo/semantics/publishedVersio