Assessment and up-scaling of CO2 exchange by patches of the herbaceous vegetation mosaic in a Portuguese cork oak woodland

Long-term eddy covariance measurements over a montado oak woodland in southern Portugal have documented a vulnerability to predicted decreases in springtime rainfall, since water availability during spring limits annual CO₂ gain, the growth of fodder for animals, and the production of cork by Quercus suber. The current study examined CO₂ exchange of three different herbaceous vegetation components distributed over montado landscapes and within the footprint of long-term landscape eddy covariance monitoring studies. Simultaneous measurements with eddy covariance at two sites and with manually operated chambers at multiple locations revealed that slow drainage of shallow basins, the onset of drying at higher sites and a high release of CO₂ below tree canopies significantly influenced the overall course of montado ecosystem gas exchange during the spring.Hyperbolic light response models were employed to up-scale and compare herbaceous gas exchange with landscape net ecosystem CO₂ flux. The up-scaling demonstrates the importance of the herbaceous understory in determining annual carbon balance of the montado and suggests a relatively small additional CO₂ uptake by the tree canopies and boles, i.e., by the aboveground tree compartment, during springtime. Annual flux totals obtained during the extremely dry year 2005 and a normal precipitation year 2006 for the oak woodland and a nearby grassland were essentially the same, indicating that both ecosystems similarly exploit available resources. Based on comparisons with additional temperate grasslands, we can visualize the montado herbaceous cover as a typical European grassland canopy, but where temperature fluctuations in winter control uptake, and where total production depends on springtime rainfall as it controls phenological events and eventually dieback of the vegetation. On the other hand, tree canopies remain active longer during late spring and early summer, modifying the montado response from that of grassland. Uncertainties in flux estimates via both chamber and eddy covariance methodologies currently prevent a full understanding of vegetation/atmosphere coupling, of the recycling of CO₂ between the understory communities and trees, and of relationships between exchange rates of individual components of the vegetation mosaic and overall carbon and water balances in montado landscapes.     

Aerial spraying ofBacillus thuringiensis var.kurstaki for the control ofThaumetopoea processionea in Turkey oak woods

Thaumetopoea processionea L. is an important oak defoliator whose outbreaks have become increasingly frequent in Europe and thus have received a great deal of attention from foresters. Field trials were carried out in central Italy (Tuscany) to test the efficacy of aerial spraying ofBacillus thuringiensis var.kurstaki [Btk] in early spring for the control of processionary infestations inQuercus cerris L. woods. The experimental sites were located in a hilly area of 1640 ha witha maximum altitude of 593 m a.s.l. and a yearly mean temperature of 10°C. Turkey oak woods were divided into three areas to be treated with 31.75 BIU ha⁻¹ (2.5l ha⁻¹) on 578 ha, 44.45 BIU ha⁻¹ (3.5l ha⁻¹) on 306 ha and 57.15 BIU ha⁻¹ (4.5l ha⁻¹) on 756 ha, respectively. Five days after treatment, larval mortality was less than 40% in the control plot, but over 60% in the treated areas. Thirteen days after treatment, larval mortality varied from 75.05% to 96.42% in the three treated areas. Surveys conducted 2 months after the treatment showed a strong decline in the number of oak processionary nests in all the treated plots. It was possible to control the pest effectively in turkey oak woods usingBtk at 31.75 BIU ha⁻¹ distributed at ultra-low volume at the time of bud opening when nonurticating larvae were present. http://www.phytoparasitica.org posting March 12, 2008.     

Pine volatiles and terpenoid compounds attractive to European xylophagous species,vectors of <Emphasis Type="Italic">Bursaphelenchus</Emphasis> spp. nematodes

The attractiveness of different combinations of volatile compounds to several scolytid and cerambycid species, potential vectors of phytoparasitic nematodes of the genus Bursaphelenchus Fuchs, was investigated in pine woods of central Italy. The blend composed of α-pinene, ethanol, ipsenol, ipsdienol and 2-methyl-3-buten-2-ol was very efficient in trapping the cerambycids Monochamus galloprovincialis, Acanthocinus griseus and Arhopalus syriacus and the scolytids Ips sexdentatus, Orthotomicus erosus and Hylurgus ligniperda. This blend is proposed for operational surveys of Bursaphelenchus spp. associated with these beetles. Comparison of the capture levels with cross-vane and funnel traps baited with α-pinene, ethanol, ipsenol, ipsdienol, 2-methyl-3-buten-2-ol and cis-verbenol revealed the higher efficacy of the cross-vane traps for the above-mentioned cerambycids and the scolytid I. sexdentatus but greater effectiveness of the funnel traps in capturing H. ligniperda and O. erosus. Cross-vane traps were more efficient in capturing large numbers of these insects. Data on non-target xylophagous beetles and predator species are also reported.     

Introduction into Italy of Gryon pennsylvanicum (Ashmead), an egg parasitoid of the alien invasive bug Leptoglossus occidentalis Heidemann

Leptoglossus occidentalis (Heteroptera, Coreidae), a Nearctic species, was accidentally introduced into Northern Italy in the late 1990s, from where it has spread throughout Europe. The bug causes abortion of immature cones of Pinus pinea L., with economic impact on the pine‐nut industry. As part of a pest control research program, the egg parasitoid Gryon pennsylvanicum Ashmead (Hymenoptera, Platygastridae) was collected from British Columbia, Canada, and legally introduced to a quarantine climatic chamber in Florence, Italy. The egg parasitoid will be tested against native non‐target heteropterans, an environmental impact assessment will be conducted, and a mass rearing method will be developed if appropriate. The ultimate goal is to release G. pennsylvanicum into Italian P. pinea forests for classical biological control of L. occidentalis.     

Physiological host range of Trissolcus mitsukurii,a candidate biological control agent of Halyomorpha halys in Europe

Journal of Pest Science - The invasive stink bug Halyomorpha halys, native to East Asia, is a severe agricultural pest of worldwide importance, and chemical insecticides are largely sprayed for its...     

The Prospective Use of Brazilian Marine Macroalgae in Schistosomiasis Control

Schistosomiasis is a parasitic disease that affects more than 250 million people. The treatment is limited to praziquantel and the control of the intermediate host with the highly toxic molluscicidal niclosamide. Marine algae are a poorly explored and promising alternative that can provide lead compounds, and the use of multivariate analysis could contribute to quicker discovery. As part of our search for new natural compounds with which to control schistosomiasis, we screened 45 crude extracts obtained from 37 Brazilian seaweed species for their molluscicidal activity against Biomphalaria glabrata embryos and schistosomicidal activities against Schistosoma mansoni. Two sets of extracts were taxonomically grouped for metabolomic analysis. The extracts were analyzed by GC–MS, and the data were subjected to Pattern Hunter and Pearson correlation tests. Overall, 22 species (60%) showed activity in at least one of the two models. Multivariate analysis pointed towards 3 hits against B. glabrata veliger embryos in the Laurencia/Laurenciella set, 5 hits against B. glabrata blastula embryos, and 31 against S. mansoni in the Ochrophyta set. Preliminary annotations suggested some compounds such as triquinane alcohols, prenylated guaianes, dichotomanes, and xenianes. Despite the putative identification, this work presents potential candidates and can guide future isolation and identification.     

Pest risk analysis of rice root-knot nematode (Meloidogyne graminicola) for the Italian territory

Meloidogyne graminicola is one of the most harmful organisms associated with rice cultivation throughout the world. Until recently, M. graminicola was present only in Asia, parts of the Americas, Madagascar and South Africa. In 2016, it was detected for the first time in mainland Europe (Northern Italy) and subsequently added to the EPPO Alert List. In this study, the risk posed by this nematode to rice in Italy was assessed using an internationally developed pest risk analysis scheme. In the risk assessment section, information about biology, pathways for entry, the likelihood of establishment, spread and negative impact of M. graminicola are reviewed. Internationally, its spread is more likely through the movement of infested host plants, soil or growing medium and non-host plant parts that may have growing medium attached, from areas where this nematode occurs. Migrant waterbirds, machinery and travellers were also considered as possible pathways for entry. The probability of establishment is very likely due to the suitable environmental conditions and the large range of host plant species present in Italy. This and the nematodes’ ability to survive for long periods in low oxygen environments make the control of M. graminicola very difficult.