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- Refuge areas favor the presence of predators and herbivores in Bt soybean: a landscape perspectivePublication . Abbate, Silvana Laura; Madeira, Filipe; Bentancur, Oscar; Altier, Nora; Pons, XavierSoybean plants that express various insecticidal proteins of the bacterium Bacillus thuringiensis have been widely adopted globally in many crop systems. This technology effectively controls the main defoliating pest species in most countries and reduces insecticide spray requirements. However, widespread use of Bt crops also generates high selection pressure against pest populations, leading to resistance concerns. Refuge areas are established to delay this phenomenon, but little is known about their other ecological functions. We evaluated the role of non-Bt soybean refuge areas regarding the abundance and richness of predator species in Bt soybean and non-Bt fields. For 2 years, herbivore and predatory arthropods were sampled in 28 soybean fields (RR/Bt) and their non-Bt soybean refuge areas (RR/noBt) in Uruguay, throughout the whole crop cycle. Landscape crop diversity (1 km radius) was characterized by its richness and evenness. Arthropod abundance and richness were analyzed using general linear mixed models. The abundance and richness of predators (Araneae, Coccinellidae, Heteroptera and Chrysopidae) found in Bt soybean were positively associated with the values recorded in refuge areas, independently of the diversity of the surrounding landscape. This relationship was not affected by changes in the distance between sampling points (within 800 m). The abundance of stink bugs and leaf-feeding caterpillars in Bt soybean was positively associated with refuge area values. Our results reinforce the importance of refuge areas, not only due to their role in resistance management, but also as preservation areas of beneficial fauna within a landscape approach to Integrated Pest Management in agroecosystems.
- Otimização do processo industrial de compostagem de bagaço de azeitona no nordeste de PortugalPublication . Hernandez Hernandez, Zulimar; Figueiredo, Daniel; Royer, Ana Caroline; Madeira, Filipe; Figueiredo, Tomás dePortugal produz anualmente cerca de 100 mil t de azeite, 5% da produção mundial. Durante o processo produtivo geram-se mais de 547 mil t/ano de bagaço de azeitona (BA). Atualmente, o BA não tem valor económico, tendo os lagares que assumir o custo de transporte até as extratoras de azeite lampante, pelo que urge procurar alternativas mais sustentáveis. O BA contém elevado teor em C orgânico (lenhina), tornando-o ideal para a elaboração de compostos de alta qualidade. No entanto é um material com elevado teor em água e fitotóxico quando não devidamente gerido. Neste trabalho, apresentam-se resultados dum ensaio experimental de compostagem a escala industrial (pilhas de 27m3 ) durante 120 dias (d), usando como matériaprima principal o BA, além de estrume de ovelha (EO) e um “agente estruturante” (AE). O ensaio permitiu testar o efeito da mistura das matérias-primas (assegurando C/N>30), doses de AE e revolvimento mecânico. Foram realizadas amostragens para determinar humidade, densidade, granulometria, cor, cinzas, pH, condutividade elétrica (CE), C total e N total, para além das relações atómicas por análises elementar (H/C, O/C) e a espectroscopia de infravermelhos (IR). Os resultados preliminares mostram que a fase termófila foi atingida nos primeiros 10 d, mantendo-se 8 semanas até a fase de maturação. Perdas de peso de até 30% nos primeiros 30 d, e razões C/N na ordem de 25 em 60 d. Aos 120 d, o composto tinha uma cor escura, ausência de odor desagradável, C/N<20 e baixa fitotoxicidade. Os espetros IR mostraram que os ácidos gordos, os polifenóis e as lenhinas são transformadas na fase inicial da compostagem. Ao reduzir o tempo da compostagem (de 9 para 5 meses), é possível reduzir os custos da compostagem convencional de BA e contribuir para a sustentabilidade da agricultura regional.
- Phenology, population trends and natural enemy complex of Illinoia liriodendri in SpainPublication . Meseguer, Roberto; Madeira, Filipe; Kavallieratos, Nickolas G.; Pons, XavierIllinoia liriodendri (Monell) (Hemiptera: Aphididae) is an Eastern North American native aphid species that infests ornamental tulip trees, Liriodendron tulipifera L. (Magnoliales: Magnoliaceae), in many localities of Spain and southern Europe. This is a comprehensive three-year study on the biology and ecology of the aphid, where its life cycle, phenology, population dynamic trends, comfort damages, natural enemy complex and its potential to control aphid populations have been investigated for the first time in Europe. The monoecic-holocyclic annual cycle of I. liriodendri has been demonstrated. The highest infestation levels were recorded in May and June, but infestation severity varied among localities. No clear trend regarding the effect of planting site (pit vs. ground) on aphid abundance was observed. A strong positive relationship between the aphid infestation severity and the honeydew dripping was recorded. There was a wide complex of natural enemies associated with the aphid. Coccinellidae were the most abundant predators (< 95%) and showed a positive numerical response to the aphid infestation. Several parasitoid species (mainly Hymenoptera: Aphidiinae and Hymenoptera: Aphelinidae) were found parasitizing I. liriodendri in Spain. The role of natural enemies as agents for controlling the aphid populations is discussed.
- Effects of temperature on the fitness of the alfalfa weevil (Hypera postica)Publication . Levi‐Mourao, Alexandre; Madeira, Filipe; Meseguer, Roberto; Pons, XavierTemperature directly influences the survival, development and reproduction of insects and limits their biological activity. The alfalfa weevil (Hypera postica Gyllenhal) is a destructive pest of alfalfa crops in Spain and in most of the alfalfa pro- duction countries. The knowledge of how temperature affects the fitness of this pest can be used to predict its activity in current or forecasted environmental conditions and to develop more accurate control strategies. Results: We evaluated the fitness of alfalfa weevil at eight constant temperatures (8–36 °C) at 4 °C intervals by using life tables and models for the description of temperature-dependent development rates. We found that most of the parameters we stud- ied were temperature dependent. Development was observed at all temperatures. However, postembryonic survival was opti- mal at 16 °C but very low at 36 °C. Adults did not reproduce at 8, 32 or 36 °C. The highest fecundity and net reproductive rate were observed at 20 °C, but the highest intrinsic rate of increase occurred at 24 °C. We predicted the phenology of the pest based on the heat needed for development, the cumulative degree days from the beginning of October to the end of May, and the day length in the study region. Conclusion: Our prediction was validated using field data reporting the first occurrence of larval instars and adults, revealing that no more than two generations are possible within an annual cycle. In a hypothetical case where average monthly temper- atures increase by 1–2 °C, the number of generations would not change.
- Otimização do processo industrial de compostagem de bagaço de azeitona no nordeste de PortugalPublication . Hernández, Zulimar; Figueiredo, Daniel; Royer, Ana Caroline; Madeira, Filipe; Figueiredo, Tomás dePortugal produz cerca de 100 mil toneladas de azeite, 5% da produção mundial. Durante o processo produtivo geram-se mais de 547 mil toneladas de bagaço de azeitona (BA). Atualmente, o BA não tem valor económico, tendo os lagares que assumir o custo de transporte até as extratoras do azeite, pelo que urge procurar alternativas mais sustentáveis. O BA contém elevado teor em C orgânico (lignina), tornando-o ideal para a elaboração de compostos de alta qualidade. No entanto é um material pastoso, com elevado teor em água e fitotóxico quando não devidamente gerido. Neste trabalho, apresentam-se resultados dum ensaio experimental de compostagem a escala industrial (pilhas de 26m3) durante 180 dias, usando como matéria-prima principal o BA, além de outras matérias-primas e um “agente estruturante” (AE). O ensaio permitiu testar o efeito da mistura das matérias-primas (assegurando C/N>40), doses de AE e arejamento manual. Foram realizadas 7 amostragens para determinar humidade, densidade, granulometria, teor em cinzas, pH, CE, C total e N total, para além das relações atómicas por análises elemental e a espectroscopia de infravermelhos FTIR. Os resultados preliminares mostram que a fase termófila foi atingida nos primeiros 10 dias, mantendo-se 8 semanas até a fase de maturação. Perdas de peso de até 30% nos primeiros 30 dias, e razões C/N na ordem de 25 em 60 dias. Aos 120 dias, o composto tinha uma cor escura, “bom cheiro”, C/N<20 e baixa fitotoxicidade. Observou-se uma rápida perda de grupos alifáticos, aumento de compostos azotados e condensação de cadeias de C, o que demostrou que os ácidos gordos, os polifenóis e as ligninas são degradados na fase inicial da compostagem. Ao reduzir o tempo da compostagem (de 9 a 4 meses), é possível abaratar os custos da compostagem convencional de BA e contribuir para a sustentabilidade da agricultura regional.
- Contribution of surrounding flowering plants to reduce abundance of Aphis nerii (Hemiptera: Aphididae) on Oleanders (Nerium oleander L.)Publication . Madeira, Filipe; Lumbierres, Belén; Pons, XavierOleander is very frequently planted as an ornamental shrub in urban areas of the Mediterranean. Its most common pest is the aphid Aphis nerii, and heavy infestations produce aesthetic damage and disturbances to the citizens, and they are frequently sprayed with insecticides in order to reduce the population density. One alternative method is conservation biological control which is enhanced by the provisioning of alternative food, refuges, and reproduction sites. In this study, the usefulness of four flowering service plants (Lobularia maritima, Calendula officinalis, Coreopsis grandiflora, and Achillea millefolium) is evaluated for aphid infestation levels and aphid natural enemy abundances. Aphid levels were consistently lower in oleander plots surrounded by service plants. Natural enemy abundances tended to be higher in plots surrounded by service plants, but significant differences could not be found until the fourth year of the study, when more lacewings, total predators, and mummies were higher in plots surrounded by service plants. On these plots, hoverflies, ladybeetles, and lacewings were the most common predators. Paragus sp. and Hippodamia variegata were the prevalent hoverfly and ladybeetle species, respectively. The potential toxicity effect on the prevalence of natural enemy species is discussed. On service plants, significantly more hoverflies were recorded on L. maritima than on C. officinalis and C. grandiflora, and more true bugs were recorded on C. officinalis and A. millefolium than on L. maritima or C. grandiflora. Our results suggest that planting service plants (such as sweet alyssum, marigold, or yarrow) surrounding oleanders can improve conservation biological control by enhancing the abundance of aphid natural enemies and thus a reduction of the abundance of A. nerii.