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- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Saissetia oleae (Olivier) (Hemiptera: Coccidae)Publication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Lacewings are common biocontrol agents against a wide range of agricultural pests.These predators are highly voracious against soft-bodied preys such as juveniles of scale insects. In this context, the present work aims to study the use of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) as biological control agent against Saissetia oleae (Olivier) (Hemiptera: Coccidae). For that, we studied the functional response of the larval instars of C. carnea to nymphs of S. oleae. Increasing densities (3, 5, 10, 15, 25 and 40) of S. oleae nymphs were offered to the three larval stages of C. carnea in a controlled laboratory environment. After 24 hours, the number of S. oleae consumed by C. carnea larva was recorded and the functional response calculated. The three larval stages of C. carnea displayed a type II functional response behavior. Prey consumption by C. carnea larvae increased with high S. oleae densities. Moreover, younger larvae showed a lower predation rate in comparison with the older ones. The search rate and handling time of the third instar larvae were lower than those of the younger larval instars, and the simulated max. attack rate of the third instar larvae was higher than those of the first and second instar larvae. Our results suggest that all larval stages of C. carnea could be important in S. oleae biological control in olive orchards, although the third larval stage of the predator was more efficient in reducing S. oleae densities than first and second C. carnea larval instars.
- A cochonilha negra, Saissetia oleae, como alimento para larvas e adultos de Chrysoperla carnea s.l.Publication . Villa, Maria; Mahzoum, Abdelkader; Benhadi-Marín, Jacinto; Pereira, J.A.As larvas de Chrysoperla carnea s.l. (Stephens) são amplamente utilizadas em programas de luta biológica devido à sua ação como predadores de insetos. Por sua vez, os adultos alimentam-se de meladas de hemípteros, pólen e néctar de flores. No olival são potenciais predadores de várias pragas. Assim, neste agroecosistema a existência de recursos alimentícios é essencial para manter as populações de C. carnea e melhorar a sua ação numa perspetiva de proteção biológica por conservação. A cochonilha negra, Saissetia oleae (Olivier), é uma praga secundaria da oliveira em grande parte da região mediterrânica. A existência desta praga pode proporcionar recursos alimentícios para as diferentes fases de desenvolvimento de C. carnea, nomeadamente, as ninfas como presas para alimentação das larvas do predador, e as meladas que o adulto excreta como fonte de energia para adultos. Assim, o objetivo deste trabalho foi avaliar o potencial de S. oleae como alimento para larvas e adultos de C. carnea. Para avaliar o efeito nas larvas, foram disponibilizadas diferentes densidades de ninfas de S. oleae a larvas de C. carnea, e avaliadas taxas de consumo; para os adultos, foram disponibilizadas meladas excretadas por S. oleae e avaliada a sobrevivência, em ambos os sexos, e fecundidade em fêmeas. Verificou-se que as larvas de C. carnea consomem eficientemente ninfas de S. oleae. Por sua vez nos adultos, o consumo de meladas melhora a sua sobrevivência em comparação ao controlo (água), mas não a reprodução, o que estará relacionado com a inexistência de proteína necessária para a formação de ovos. Assim, numa estratégia de proteção biológica por conservação, baixos níveis populacionais da praga podem contribuir para a manutenção e aumento de crisopídeos no olival
- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) Larvae on Saissetia oleae (Olivier) (Hemiptera: Coccidae): implications for biological controlPublication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a voracious predator of soft-bodied insects such as juveniles of scale insects and the black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) is an important pest of several crops, such as the olive tree. However, the predatory effciency of C. carnea on S. oleae has been unstudied yet. The present work aimed to study the functional response of larvae of C. carnea fed on S. oleae nymphs. In a controlled laboratory environment, increasing densities of S. oleae second and third nymph stages were offered to newly emerged specimens of the three larvae instars of C. carnea. After 24 h, the number of killed S. oleae was recorded and the functional response of C. carnea was assessed. The three larval stages of C. carnea displayed a type-II functional response, i.e., killed prey increased with higher S. oleae densities up to a maximum limited by the handling time. The attack rate did not significantly differ among the three instars while the maximum attack rate was significantly higher for the third instar. The handling time of the first larval instar of C. carnea was higher than that of the third instar. Our results demonstrated that S. oleae could act as a food resource for all larval stages of C. carnea. Furthermore, the third larval stage of the predator was the most effcient in reducing S. oleae densities. These results suggest that C. carnea larvae could contribute to S. oleae control in sustainable agriculture.
- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Saissetia oleae (Olivier) (Hemiptera: Coccidae)Publication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Lacewings are common biocontrol agents against a wide range of agricultural pests. These predators are highly voracious against soft-bodied preys such as juveniles of scale insects. In this context, the present work aims to study the use of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) as biological control agent against Saissetia oleae (Olivier) (Hemiptera: Coccidae). For that, we studied the functional response of the larval instars of C. carnea to nymphs of S. oleae. Increasing densities (3, 5, 10, 15, 25 and 40) of S. oleae nymphs were offered to the three larval stages of C. carnea in a controlled laboratory environment. After 24 hours, the number of S. oleae consumed by C. carnea larva was recorded and the functional response calculated. The three larval stages of C. carnea displayed a type II functional response behavior. Prey consumption by C. carnea larvae increased with high S. oleae densities. Moreover, younger larvae showed a lower predation rate in comparison with the older ones. The search rate and handling time of the third instar larvae were lower than those of the younger larval instars, and the simulated max. attack rate of the third instar larvae was higher than those of the first and second instar larvae. Our results suggest that all larval stages of C. carnea could be important in S. oleae biological control in olive orchards, although the third larval stage of the predator was more efficient in reducing S. oleae densities than first and second C. carnea larval instars.
- Monitorização das populações de Anarsia lineatella Zeller e Grapholita molesta (Busck) em amendoais localizados em Trás-os-Montes (Portugal)Publication . Barreales, David; Santos, Sónia A.P.; Benhadi-Marín, Jacinto; Pereira, J.A.; Ribeiro, A.C.A amendoeira (Prunus dulcis Mill. ) é uma espécie cultivada na região de Trás-os-Montes onde o seu cultivo tem aumentado nos últimos anos. Entre os diferentes insetos que podem causar estragos na amendoeira apresentam-se os lepidópteros e o conhecimento da dinâmica das suas populações torna-se importante para se poderem tomar decisões no que respeita à prevenção e ao combate a estas pragas. O objetivo deste trabalho foi a monitorização das populações de Anarsia lineatella Zeller e Grapholita molesta (Busck) na localidade de Alfândega-da-Fé. A monitorização de A. Lineatella e G. molesta, foi feita em dois amendoais, um regado e outro de sequeiro. No amendoal regado, o principal cultivar foi Ferragnès e como polinizador Lauranne. No amendoal de sequeiro o cultivar principal foi Masbovera e Glorieta como polinizador. Em cada amendoal instalaram-se três armadilhas delta com feromona sexual para a captura de cada uma das pragas. Estas armadilhas permaneceram instaladas desde o início de abril até finais de novembro em dois anos consecutivos, 2015 e 2016. Semanalmente, realizou-se a identificação e contagem dos indivíduos capturados e as feromonas foram substituídas com uma periodicidade de cinco semanas. Para cada data foi calculada a média (± EP) da abundância de cada espécie. Nos dados obtidos durante os dois anos, não se verificaram diferenças significativas entre as populações de A. lineatella e G. molesta capturadas nas diferentes variedades de amendoeira, nem entre amendoal regado e de sequeiro. Os níveis populacionais mais elevados atingiram-se no mês de outubro, no caso de A. lineatella, e no mês de julho, no caso de G. molesta. nos dois anos de estudo. Destacam-se os picos médios de capturas mais elevados em 110 indivíduos para /\. lineatella no ano 2015 e 22 individuos de G. Molesta no ano 2016. Com estes resultados foi possível conhecer melhor a dinâmica populacional destas duas pragas que atacam a amendoeira para assim fazer recomendações a agricultores e técnicos sobre quais podem ser as melhores estratégias para prevenir os ataques destas pragas e quais podem ser os momentos ótimos para efetuar tratamentos fitossanitários.
- Sampling and distribution pattern of Trioza erytreae Del Guercio, 1918 (Hemiptera: Triozidae) in citrus orchardPublication . Benhadi-Marín, Jacinto; Pereira, Luís Fernando; Rodrigues, Isabel; Fereres, Alberto; Pereira, J.A.Developing efficient sampling protocols is essential to monitor crop pests. One vector of the citrus disease HLB, the African citrus psyllid Trioza erytreae Del Guercio, 1918 (Hemiptera: Triozidae), currently threatens the lemon industry throughout the Mediterranean region. In this work, a pool of sampling methods devoted to monitoring the population of T. erytreae was compared, its spatial distribution in the orchard was assessed, and the minimum sampling effort for the best sampling method was estimated. Three lemon orchards in North-western Portugal were sampled for one year using two types of yellow sticky traps (standard yellow and fluorescent Saturn yellow), B-vac sampling and sweep net sampling. The method that best performed, in terms of cost-efficiency, was the yellow sticky traps. The two colours of the sticky traps tested did not yield a significantly different number of catches. The spatial distribution throughout the orchards was found to be aggregated towards the borders. A minimum of three sticky traps per hectare was found to be enough to estimate the population at 90% accuracy for the mean during the outbreak. These results should help to monitor and anticipate outbreaks that may even colonize neighbour orchards. Studies on the local dispersion patterns of T. erytreae throughout the orchard are mandatory to further refine and optimize efficient monitoring protocols.
- Host plant preference of Trioza erytreae on lemon and bitter orange plantsPublication . Benhadi-Marín, Jacinto; Garzo, Elisa; Moreno, Aránzazu; Pereira, J.A.; Fereres, AlbertoTrioza erytreae, the African citrus psyllid, is a vector of Candidatus Liberibacter spp., the causal agent of the citrus greening disease or Huanglongbing (HLB). The spread of the vector throughout the Iberian Peninsula has been continuous since its introduction in mainland Spain in 2014. The patterns of host preference and feeding behaviour largely depend on olfactory cues. Understanding these patterns is crucial to prevent further dispersion and develop management measures against the pest. In this work, a series of settlement, olfactometric, probing, and feeding experiments were conducted to assess the host preference of T. erytreae for lemon or bitter orange plants. The settlement experiment provided evidence on the preference of both sexes of T. erytreae for lemon plants, whereas males did not show any significant choice pattern in the case of the olfactometric assays. Forty EPG variables were analysed to describe and compare the probing and feeding behaviour of T. erytreae on lemon and bitter orange plants. The EPG variables indicated that T. erytreae has some difficulties in accepting the phloem of bitter orange plants. This suggests that lemon plants would be a better source for the acquisition of Candidatus Liberibacter asiaticus (CLas) by T. erytreae since the psyllid spends much longer periods feeding from the phloem on lemon than on bitter orange.
- Endophytic and epiphytic phyllosphere fungal communities are shaped by different environmental factors in a Mediterranean ecosystemPublication . Gomes, Teresa; Pereira, J.A.; Benhadi-Marín, Jacinto; Lino-Neto, Teresa; Baptista, PaulaThe diversity and potential factors that influence fungal assemblages in the phyllosphere ofMediterranean tree species have been barely studied, especially when endophytic and epiphytic communities are simultaneously considered. The endophytic and epiphytic fungal communities in the phyllosphere of olive tree, a typically Mediterranean species adapted to grow under adverse climatic conditions, were studied for evaluating differences between both fungal communities, and examine whether different abiotic (climate-related) and biotic (plant organ) factors play a role in structuring these communities. Both communities differed in size and composition, being the epiphytic community richer and more abundant, displaying a dominance of melanized fungi. Season was the major driver of community composition, ~ especially of epiphytes. Other drivers shaping epiphytes were wind speed and temperature. Plant organ, rainfall, and temperature were drivers of endophytic composition. In contrast, limited variation is provided by canopy orientation, but its effect was distinct among seasons. In conclusion, epiphytic and endophytic communities are not driven by the same factors. Several sources of variation interact in complex ways to form and maintain the phyllosphere fungal community in Mediterranean climates. The importance of climatic parameters for these fungal communities suggests that they are likely to be affected by future climate change.
- Predatory potential of Forficulidae (Dermaptera) on the olive fly Bactrocera oleaePublication . Neto, Marco Aurélio; Benhadi-Marín, Jacinto; Gonçalves, Maria de Fátima; Villa, Maria; Pereira, J.A.Earwigs (Dermaptera: Forficulidae) are omnivorous insects, feeding on a variety of plants and animal material and are described as natural control agents of pests in several agroecosystems. Earwigs are abundant in olive orchards and their adult stage overlaps in time and space with the pupae stage of the main olive pest, the olive fly Bactrocera oleae (Rossi). However, the role of earwigs as natural control agents of B. oleae is almost unknown. The present work aimed to study the functional response of female and male earwigs on olive fly pupae in order to analyse their potential ability to limit this pest. Increasing densities of pupae were offered to starved earwigs in a controlled laboratory environment. After 24 h, the number of attacked pupae was recorded. The type of functional response, handling time, and attack rate of the earwigs was assessed. Our results disentangle the potentiality of earwigs as predators of B. oleae during the pupae stage and provide relevant information for further studies and applications.
- Diversity of predaceous arthropods in the almond tree canopy in Northeastern Portugal: a methodological approachPublication . Benhadi-Marín, Jacinto; Pereira, J.A.; Barrientos, José A.; Bento, Albino; Santos, Sónia A.P.The almond tree is an economically important crop in Mediterranean regions. However, knowledge about the biodiversity of natural enemies that may be useful as biocontrol agents, is scarce. The objectives of this work were (1) to study the diversity of predaceous arthropods and (2) establish a suitable sampling protocol for arthropods of the almond tree canopy. Between April and October of 2007-2008, 25 randomly selected trees were sampled in an organic almond grove located in the northeast of Portugal using the beating technique. The specimens collected were counted and identified and the sampling protocol was established by using the accumulation curves and the seasonal richness peaks of the most abundant groups of natural enemies. A total of 1856 and 1301 arthropods were captured respectively in 2007 and 2008, where Araneae, Coccinellidae and Formicidae were the most abundant groups. A total of 14 families and 29 species of spiders were identified as being Linyphiidae, Philodromidae, Thomisidae, Araneidae and Oxyopidae, the five most abundant families in both years. In the Coccinellidae and Formicidae communities 15 and 13 species were identified, respectively. According to taxa accumulation curves, the minimum sampling effort that provided a reliable picture of the biodiversity was established in 11 samples. Moreover, considering the seasonal richness distribution, it would be advisable to concentrate the sampling period from the beginning of July to the harvesting of almonds. This protocol might generate accurate replicate samples to estimate species richness when the effect of agricultural management is studied.