1,721,333 research outputs found
Underestimated impact of Red Palm Weevil introduction on iandscape biodiversity: the help of the molecular tools
No full textAlien species have been introduced both accidentally and intentionally. The last are and have been motivated by economic, environmental and social considerations (NOBANIS, 2010), as in the case of many palm species (Phoenix canariensis, P. dactylifera, Washingtonia filifera, W. robusta) in Sicily. These Arecaceae are important in the urban areas and they contribute to the typical Sicilian Panorama. On the other hand the accidental introduction of invasive alien species can be one a cause of the loss of native biodiversity, especially severe on islands and other isolated ecosystems. Phytophagous insects can cause biodiversity losses and may also have a strong impact on the economy of the island and on the landscape. The adverse effects of invasive alien insects are illustrated by specific examples from Sicily, including the multiple impacts of the invasive weevil Rhynchophourous ferrugineus (Manachini et al., 2012), native to Malesia but quickly spread throughout Europe where it preferably attacks P. canariensis. It is noted that RPW aggressively spreads from P. canariensis to other not native hosts (eg. Washingtonia spp., Sabal spp.) and to native palm Chamaerops humilis L. (Arecaceae). This poses a threat to natural plant communities, biodiversity and landscape (Manachini et al., 2012). There is evidence that in a new territory the invasive species populations for some time exist in a kind of latent state, during which due to repeated invasions and hybridization as well as the mutations the level of genetic diversity is restored, which is usually reduced due to genetic processes occurring in the course of invasion (genetic drift, bottleneck, founder effect) (McRay & Latta 2002). Moreover there was reported that change in the host preferences could lead or due to genetic differences and to a formation of different species or sub-species (Drès & Mallet, 2002). It is known that for weevil species, host choice did not only depend on host phenology, but also on other physical and chemical factor, and this could be link to genetic differentiation. To make a clear assignment of weevil species or race independently of possible morphological plasticity, we decided to use molecular markers. These tools have the additional advantage of being applicable to both immature and adult individuals. We used a mitochondrial and a nuclear marker, because comparison between the two can detect also hybridization. The mitochondrial marker was the COI gene, which encodes for the first subunit of the cytochrome oxidase, one of the most frequently sequenced genes used in insect phylogeny (Caterino et al., 2000), already identified by the authors for RPW. Mitochondrial and nuclear sequences data showed that RPWs collected in different areas can be recognised at all different instars by molecular analysis and that all weevils came from different hosts belong to the same specie, and closed population, this lead to recognised the potential risk of extend its attack more on C. humilis. Biological data on the RPW form different infested palms confirm this potential danger that can lead to a change in the native biodiversity sustained by the presence of C. humilis
Insects and nematodes parassites of Oryza sativa: from traditional to biomolecular control.
No full textUso di tecniche biomolecolari per la distinzione di biotipi mono, bivoltini e polivoltini di Ostrinia nubilalis Hb. (Lepidoptera:Crambidae)
No full textOverview on the studies conducted in Italy on the effects of Bt GM plants on non-target organisms.
No full textAlien Insect Impact on Cultural Heritage and Landscape: an Underestimated Problem
Full text linkThe impact of alien invasive insects on cultural heritage and landscapes is very often neglected; even though, more than 50% of species that threaten cultural heritage in Europe are of exotic origin. In addition they are more aggressive. Several examples and a description, are given of the most dangerous alien insects present in heritage sites that constitute a risk for the conservation of cultural property: museum collections, libraries, archives and historic buildings. Globalisation has increased this phenomenon but traces of the accidental introduction of insect pests have occurred since Roman times. The paper discusses the need to implement an estimation of the costs that arise from the damage caused by these species and the lack of specific legislative aspects
Effects of transgenic corn on Lydella thompsoni Herting (Diptera:Tachinidae) parasitoid of Ostrinia nubilalis Hb. (Lepidoptera Crambidae)
No full textCompatibility of Chemical and Biological Pesticides.
No full textIn the majority of crop systems today, emphasis is still placed on single technologies such as the use of pesticides, host plant resistance, and biocontrol, consideration rarely being given to their interaction (1). However, an important approach that could be taken in integrated pest management (IPM) programs is the use of biological pesticides together with a rational use of chemical pesticides. In fact, when a range of pests is present, or when only one method is not efficient, there may often be economic and environmental advantages in combining two or more control methods. Such methods need to be compatible with each other, as incompatibility can lead to loss in effectiveness, increased toxicity to humans and other nontarget organisms, the development of pesticide resistance, major product loss, and crop injury. Some information on the selectivity of most pesticides to natural enemies of pests is already known, but data on the compatibility of chemical and specific biopesticides are often limited and are sometimes conflicting (2)
Confronto tra la nematofauna delle monoculture di mais e quella dei sistemi erbacei
No full textGli studi sugli effetti dell'agricoltura sulla biodiversità del suolo sono diventati molto importanti, al fine di proteggere la salute dell'ambiente e migliorare la qualità dell'agricoltura. Le comunità di nematodi hanno dimostrato di offrire un potente strumento ecologico per valutare gli effetti delle pratiche agricole sul suolo. La ricerca è stata condotta in una monocoltura di mais (della durata di 20 anni) e in un ecosistema erbaceo seminaturale, dominato da Festuca spp. e Trifolium spp.. Ciascun sistema è stato sottoposto a due diverse pratiche di gestione delle colture (input alto (H) e basso (L)). L'obiettivo era quindi quello di studiare gli effetti di due diversi ecosistemi e diverse pratiche agricole sul suolo, utilizzando i nematodi come bioindicatori. Il confronto è stato effettuato sulla composizione generale, la struttura trofica e la biodiversità della nematofauna raccolta in tutti i sistemi. Una maggiore abbondanza di nematodi è stata registrata nella monocoltura di mais ad alto input (336 individui/100 g di suolo) mentre quella più bassa è stata trovata nel basso input dei prati (33 individui/100 g di suolo). Complessivamente, 20 famiglie e 32 generi abitavano tutti i sistemi, e il numero dei generi e la composizione erano piuttosto differenti. In tutti i sistemi i batteriofagi erano il gruppo trofico più abbondante, variando tra il 97% nell'alto input della monocoltura e il 76% nel basso input dei prati. I fungivori e i fitofagi erano più abbondanti nei prati che nelle monocolture. Gli onnivori sono stati trovati in entrambi gli input di mais in una percentuale molto bassa (<5%). La minor biodiversità è stata riscontrata nell'alto input della monocoltura. Diversi generi infatti sono stati rinvenuti solo nelle praterie come Tylenchorhynchus e diversi predatori. Ciò indica che le monocolture hanno un impatto negativo sulla composizione dell'ecosistema e sulla successione ecologica della nematofauna, come indicato anche dall'indice di maturità. Inoltre, la biodiversità e gli indici ecologici hanno mostrato una rete alimentare del suolo non arricchita e non strutturata e un ecosistema povero per la monocoltura. I dati confermano ancora una volta che le monocolture riducono la biodiversità naturale della fauna del suolo.The studies of the effects of agriculture on biodiversity have become very important, in order to protect environment health and to improve agriculture quality. Nematode communities have proved to offer a potent ecological tool for assessing the effects of agricultural practices on soil environment. The research was carried out in a 20-years maize monoculture and in a semi-natural grass ecosystem, dominated by Festuca spp. and Trifolium spp.. Each system was submitted to two different crops management practices (inputs high
(H) and low (L)). Thus the aim was to study the effects of two different ecosystems and different agricultural practices on soil, using nematodes as bioindicators. Comparison was done on general composition, trophic structure and biodiversity of the nematofauna collected in all systems. Higher nematode abundance was recorded in the high input maize monoculture (336 individuals/100 g soil) while the lower one was found in the low input of the grassland (33 individuals/100 g soil). Altogether, 20 families and 32 genera inhabited all the systems, and the number of genera and the composition were rather different. All across the systems bacterial feeders were the most abundant trophic group, ranging between 97% in the high input of monoculture and 76% in the low input of the grassland. Fungal feeders and phytophagous were more abundant in the grassland than in the monoculture. The lower biodiversity was recorded in the H input of monocolture. Several genera were recorded only in the grasslands, such as Tylenchorhynchus, and several predators. This indicate that the monoculture have a negative impact on the ecosystem composition and ecological nematofauna succession, as indicated also by Maturity Index. Moreover, the biodiversity and ecological indices showed a non-enriched and non-structured soil food web and a poor ecosystem for the monocolture. Whereas, in both inputs of the grassland all the indices suggested that the communities were well structured and well spread over the genera and less disturbed. Data confirm again that monocolture decrease the natural biodiversity of the soil fauna
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