Efficiency of biological control of Gonipterus platensis (Coleoptera: Curculionidae) by Anaphes nitens (Hymenoptera: Mymaridae) in cold areas of the Iberian Peninsula: Implications for defoliation and wood production in Eucalyptus globulus
Reis A.R.,University of Lisbon |
Reis A.R.,Altri Florestal SA |
Ferreira L.,Altri Florestal SA |
Tome M.,University of Lisbon |
And 2 more authors.
Forest Ecology and Management | Year: 2012
Sustainable management of forest plantations and cost-effective control strategies depend on previous estimations of the economic level of damage caused by the pests. The eucalyptus weevil, a key pest of Eucalyptus plantations worldwide, is mainly controlled using classical biological control, using the mymarid egg-parasitoid Anaphes nitens (Girault). Nevertheless, in several temperate regions, the parasitoid fails to reduce the weevil populations to economically sustainable levels. This study attempts to (i) relate the efficiency of the parasitoid with climate variables, (ii) relate the level of damage caused by the weevil with the rate of parasitism, (iii) estimate the implications of weevil damage on wood production. Weevil density, damage caused by defoliation on the upper crown and parasitism rates were monitored in 2007, in 34 Eucalyptus globulus stands. Elevation, temperature and precipitation were assessed by using the Worldclim database. Using historic inventory data, wood production was projected to an age of 10. years, prior to the arrival of the weevil, and compared with current data for the same stands.Parasitism rate by A. nitens was a key element explaining weevil density and tree defoliation, r 2=0.37 and 0.41 (p<0.001), respectively. Significant relationships between parasitism rates and maximum temperature of the winter months (MaxTw), r 2=0.55 and elevation r 2=0.59 (p<0.001) were found. Other climatic variables, such as temperatures of the warmest months and precipitation, were not significantly related to parasitism rates. An upper threshold limit for the efficiency of the parasitoid appears for MaxTw of 10-11°C. The mean percentage of parasitism was low 10.1% (±4.9) for MaxTw below 10°C, increasing to 70.9% (±3.8) above 11.5°C. A reduction of the efficiency of A. nitens due to differences in the climatic niches of both the host and the parasitoid is hypothesised. The lower temperature threshold in particular, is of paramount importance for this host-parasitoid system. In consequence, in colder areas MaxTw<10°C, a defoliation of 74.1% was attained. Wood volume (projected to the age of 10years) was estimated to decrease to 51% in the affected areas in 2004-2006, compared to the previous period of 1995-1998. Estimated loss in wood volume increased exponentially reaching 43% and 86%, for 75% and 100% of tree defoliation, respectively. Therefore, considering the increase in the economic costs calculated for these regions, due to the high defoliation caused by the weevil, research into alternative control strategies is urgently needed. © 2012 Elsevier B.V.
Miranda I.,University of Lisbon |
Gominho J.,University of Lisbon |
Araujo C.,Altri Florestal S.A. |
Pereira H.,University of Lisbon
European Journal of Forest Research | Year: 2014
Thirty families of Eucalyptus globulus L., established in a first-generation open-pollinated progeny test, were evaluated for the production of heartwood. Five trees of each family were harvested at 9 years of age, total tree height was measured and a cross-sectional disc was removed at 25 % stem height to estimate the amount of heartwood. The heartwood proportion of the stemwood cross-sectional area averaged 41 % with significant between-family variation (P = 0.016) ranging from 27 to 53 %. There were also important within-family differences with coefficients of variation of the mean between 4 and 48 %. Moderate heritability values were obtained for heartwood diameter and proportion (h 2 = 0.31 and 0.23, respectively) but low estimates were found for sapwood width (h 2 = 0.17). Strong positive genetic and phenotypic correlations of heartwood diameter were found with stem DBH and with heartwood proportion. Both correlation estimates indicated that larger trees tended to have more heartwood. The results indicate that there is an opportunity to reduce heartwood content in E. globulus through selection and breeding. © 2013 Springer-Verlag Berlin Heidelberg.
Braganca H.,Instituto Nacional Of Investigacao Agraria E Veterinaria Ip |
Diogo E.L.F.,Instituto Nacional Of Investigacao Agraria E Veterinaria Ip |
Neves L.,Altri Florestal SA |
Neves L.,Institute of Experimental and Technological Biology IBET |
And 4 more authors.
Forest Pathology | Year: 2016
The Eucalyptus pathogen Quambalaria eucalypti has been reported from several subtropical and tropical countries of the Southern Hemisphere. During the course of a nationwide monitoring programme aimed at the detection of pathogens in commercial eucalypt plantations in Portugal, Q. eucalypti was found affecting Eucalyptus globulus. The identity of the pathogen was confirmed by sequence analyses of the internal transcribed spacer (ITS) region of the rDNA operon, as well as morphological characteristics. Quambalaria eucalypti is widespread throughout the eucalypt-producing areas of Portugal. Pathogenicity studies revealed that different host genotypes showed various degrees of susceptibility to the pathogen. To our knowledge, this is the first report of Q. eucalypti on Eucalyptus spp. in Portugal and in the Northern Hemisphere. © 2016 Blackwell Verlag GmbH.
Correia B.,University of Aveiro |
Pinto-Marijuan M.,ITQB Institute Tecnologia Quimica e Biologica |
Pinto-Marijuan M.,University of Barcelona |
Neves L.,Institute of Experimental and Technological Biology IBET |
And 9 more authors.
Physiologia Plantarum | Year: 2014
Eucalyptus plantations are among the most productive forest stands in Portugal and Spain, being mostly used for pulp production and, more recently, as an energy crop. However, the region's Mediterranean climate, with characteristic severe summer drought, negatively affects eucalypt growth and increases mortality. Although the physiological response to water shortage is well characterized for this species, evidence about the plants' recovery ability remains scarce. In order to assess the physiological and biochemical response of Eucalyptus globulus during the recovery phase, two genotypes (AL-18 and AL-10) were submitted to a 3-week water stress period at two different intensities (18 and 25% of field capacity), followed by 1 week of rewatering. Recovery was assessed 1 day and 1 week after rehydration. Drought reduced height, biomass, water potential, NPQ and gas exchange in both genotypes. Contrarily, the levels of pigments, chlorophyll fluorescence parameters (Fv/Fm and φPSII), MDA and ABA increased. During recovery, the physiological and biochemical profile of stressed plants showed a similar trend: they experienced reversion of altered traits (MDA, ABA, E, gs, pigments), while other parameters did not recover (φPSII, NPQ). Furthermore, an overcompensation of CO2 assimilation was achieved 1 week after rehydration, which was accompanied by greater growth and re-establishment of oxidative balance. Both genotypes were tolerant to the tested conditions, although clonal differences were found. AL-10 was more productive and showed a more rapid and dynamic response to rehydration (namely in carotenoid content, φPSII and NPQ) compared to clone AL-18. © 2013 Scandinavian Plant Physiology Society.
Pinto G.,University of Aveiro |
Araujo C.,Altri Florestal SA |
Santos C.,University of Aveiro |
Neves L.,Altri Florestal SA |
Neves L.,Institute Biologia Experimental e Tecnologica IBET
Southern Forests | Year: 2013
Forest tree improvement programs benefit from the emergence of new biotechnological strategies that complement plant developmental biology and discovery of genes associated with complex multigenic traits. Recently, significant progress has been made in the area of plant regeneration via somatic embryogenesis (SE) for economically important tree species (e.g. pines). These advances have opened up new scenarios for deployment of new high-performance clonally replicated planting stock to forest plantations and may also be a valuable tool for the development of efficient gene transfer techniques. Although high rates of plant propagation from axillary shoot proliferation can be achieved easily in many Eucalyptus species, even higher multiplication rates through SE have been recorded in other tree species. If the clonal propagation of Eucalyptus through SE proves to be an effective propagation method, it has the potential to meet the increasing industrial demands for high-quality uniform materials and to rapidly capture the benefits of breeding programs. Since 2002 a reproducible protocol for SE induction from mature zygotic embryos of E. globulus has been available. However, for SE to be useful in E. globulus improvement programs, the frequency of SE initiation, maturation, germination and acclimatisation needs to be improved and controlled. If this technology could be extended to elite germplasm, it would become an economically feasible tool for large-scale production and delivery of improved planting stock. This is one of the greatest current challenges in Eucalyptus tissue culture. In this review we update the most important aspects of SE in Eucalyptus with particular emphasis on E. globulus. We highlight both genetic control and the influence of different environmental factors in the SE process (e.g. medium composition, antioxidants, light and plant growth regulators), from induction to plant acclimatisation in both primary and secondary SE. © 2013 Copyright NISC (Pty) Ltd.
Mycosphaerella and Teratosphaeria species associated with Mycosphaerella leaf disease on Eucalyptus globulus in Portugal [Especies de Mycosphaerella y Teratosphaeria asociadas con la enfermedad Mycosphaerella de las hojas en Eucalyptus globulus en Portugal]
Silva M.C.,Instituto Nacional dos Recursos Biologicos |
Machado H.N.,Instituto Nacional dos Recursos Biologicos |
Neves L.,Altri Florestal S.A |
Araujo C.,Altri Florestal S.A |
Phillips A.J.L.,New University of Lisbon
Forest Systems | Year: 2012
Plantations of Eucalyptus globulus represent the main source of wood for the pulp and paper industry in Portugal and are affected by the complex of Mycosphaerella and Teratosphaeria species (Mycosphaerella leaf disease), which is an important foliage disease worldwide. This disease affect mainly young trees with juvenile-phase foliage, causing premature defoliation, decreased growth and wood production. Species of Mycosphaerella sensu lato reported on eucalypts in Portugal are M. communis, M. heimii, M. lateralis, M. madeirae, M. marksii M. walkeri, T. africana, T. molleriana, T. nubilosa and T. parva. In order to complete the survey, symptomatic leaves were collected from Eucalyptus globulus plantations. Morphological and molecular characterization was used to give an indication of the species occurrence and most frequent species (T. nubilosa) and the composition of the MLD complex that did not change after the latest review.