Le infrastrutture ecologiche come elemento funzionale nella gestione della biodiversità degli agrosistemi, con particolare riferimento al vigneto

Molti studiosi, già da diverso tempo, hanno messo in risalto l’importanza della diversità vegetale negli agroecosistemi sull’aumento della presenza di artropodi utili che contribuiscono al contenimento delle specie dannose. In quest’ambito una strategia di difesa per mantenere alto il livello di biodiversità riguarda l’uso delle cosiddette “infrastrutture ecologiche” o “aree di compensazione ecologica”, cioè siepi o fasce di vegetazione adiacenti al campo coltivato o al suo che forniscono ospiti alternativi e siti rifugio per predatori e parassitoidi di insetti dannosi, aumentando in tal modo l’abbondanza dei nemici naturali e la colonizzazione delle colture confinanti. Alcuni lavori di campo hanno testato i concetti di ecologia del paesaggio applicata all’agricoltura, come ad esempio l’uso di corridoi biologici per contrastare insetti dannosi, evidenziando che l’uso di corridoi vegetazionali, interrompendo le monocolture, fungono da tramite per la dispersione di nemici naturali all’interno del campo, aumentando così il loro impatto sulle popolazioni dei fitofagi. La composizione delle specie costituenti la vegetazione circostante e la distanza alla quale i nemici naturali si disperdono nella coltura hanno grande influenza sull’abbondanza e diversità di insetti entomofagi all’interno di un campo. Risulta di rilevante importanza la gestione degli habitat, come forma di controllo della conservazione biologica allo scopo di creare adeguate infrastrutture ecologiche all’interno del paesaggio agrario, fornendo risorse di cibo, prede alternative e ripari ai nemici naturali. Nell’ambito del vigneto, l’incremento della diversità botanica ha apportato benefici soprattutto rilevabili nelle relazioni tra tignole e antagonisti, tra cicaline e i parassitoidi 4-2013 22 del genere Anagrus e tra acari e predatori quali acari Fitoseidi. È da tenere presente, però, che nonostante gli aspetti positivi delle infrastrutture ecologiche evidenziati, in alcune aree viticole possono verificarsi effetti sfavorevoli in relazione ad alcuni fitofagi quali cicaline, soprattutto quelle vettrici di fitoplasmi e virosi, cocciniglie e fillominatori. Vengono riportati i diversi studi finora effettuati in Italia e all’estero (paesi europei ed extra-europei).Ecological infrastructures as a functional element in the management of biodiversity of agroecosystems, with particular reference to the vineyard Many researchers have emphasized the importance of plant diversity in agro-ecosystems on increasing the presence of beneficial arthropods that contribute to the control of harmful species. In this context, a defense strategy to maintain a high level of biodiversity is the use of so-called “ecological infrastructure” or “ecological compensation areas”, i.e. hedges or strips of vegetation adjacent to the cultivated field or inside. These sites provide alternate hosts and refuge for predators and parasitoids of pests, thereby increasing the abundance of natural enemies and colonization of neighboring crops. Some field studies have tested the concepts of landscape ecology applied to agriculture, such as the use of biological corridors to control harmful insects that breaking monocultures, are the bridge to the dispersal of natural enemies in the field, increasing their impact on the pests populations. The different species of the surrounding vegetation and the distances that natural enemies disperse into the cropping system have a great influence on the abundance and diversity of beneficial insects. The habitat management is an aspect of conservation biological control using the appropriate ecological infrastructure in the agricultural landscape that provides resources for food, shelter and alternative prey to enhance natural enemies. In vineyards, the enhancement of botanical diversity has beneficial effects especially in the relationships between grape moths and antagonists, leafhoppers and parasitoids as Anagrus spp. and mites and predators as Phytoseiid mites. Despite the positive aspects of ecological infrastructures in the vineyard, unfavorable effects may occur in particular viticultural areas in relation to some pests such as leafhoppers, especially those vectors of grapevine phytoplasma and viruses diseases, scale and leafminers insects. In the paper we report the state of studies carried out in Italy, Europe and other world countries on the role of natural hedges and floral resources in supporting predatory insects with particular reference to Coccinellids and parasitoids of genus Anagrus and Trichogramma and associated natural enemies with tripids. In addition, we report briefly studies on the ecological effectiveness on species richness and abundance of animal groups and pollinators

Effects of essential oils of Origanum vulgare L. (Fam. Labiatee), Pelargonium odoratissimum L. (Fam. Geraniaceae) and Syzygium aromaticum L. (Fam. Mirtaceae) on mortality of Aphis gossypii Glover (Homoptera: Aphidiidae) in laboratory

The cotton aphid, Aphis gossypii Glover (Homoptera: Aphidiidae), is a cosmopolitan and highly polyphagous species causing serious economic damage to numerous plants including Cucurbitaceae. The use of synthetic insecticides represent the main method of control of this aphid, often resulting in resistance to all the major insecticide group. The use of natural products, such as essential oils (EOs), has increased in recent years because they have advantages in reduction of this resistance. Within this research area, we have implement and evaluate the applications of EOs that aim at reinforcing knowledge on the control of this aphid. We investigated the topical application of the EOs of Origanum vulgare L. (oregano), Pelargonium odoratissimum L. (cloves) and Syzygium aromaticum L. (geranium bourbon) by means the Potter tower on 1st instar nymphs under laboratory conditions. In our results, mortality response to EOs tested was dose-dependent and depending on the time from the treatment. It is remarkable that already after 24 hours of exposure to treatments, all three EOs caused mortality. Highest mortality was detected after 48 at doses of 1200 μl/l with values of 52%, 67% and 69% for clove, geranium and oregano, respectively. The probit analysis after 24 hours revealed that the lowest DL50 was detected for oregano (562.34 μl/l), followed by geranium (707.95 μl/l) and clove (954.99 μl/l) EOs. The results highlight a potential use of these EOs in the pest control being less toxic to the plants unlike chemical-based insecticides

Assessment of the insecticidal activity of five essential oils used against the subterranean termite Reticulitermes lucifugus (Rossi) (Blattodea, Rhinotermitidae) in laboratory

Among Reticulitermes genus the most abundant species living in Italy is Reticulitermes lucifugus Rossi. This termite is very dangerous to wooden structures of artistic heritage and buildings. The traditional control of R. lucifugus is very difficult resulting in negatively impact on the environment, therefore the use of phytochemical, such as essential oils (EOs), could lead to an alternative to synthetic insecticides, with advantages in reducing environmental risks. In this work we investigated the insecticidal activity of EOs of Citrus bergamia Risso, Syzygium aromaticum L., Foeniculum vulgare Mill., Pelargonium odoratissimum L., and Origanum vulgare L. by inhalation against R. lucifugus workers. It is the first study to examine the efficacy of EOs on this termite species. Results showed that after 24 hours of treatment exposure, mortality occurred in all treatments and was dose-dependent, increasing when the treatment dose increased. At the lowest dose (2.5 μl/l), oregano, clove, and geranium EOs resulted in mortality of more than 80%. Oregano EO was the most active already at low doses, while fennel EO was the least effective. 24 hours after the treatment, the lowest DL50, obtained by the dose-response analysis, was detected for oregano EO (1.21 μl/l), followed by those of EOs of clove (1.28 μl/l), geranium (1.73 μl/l), fennel (2.20 μl/l), and bergamot (2.88 μl/l). This study highlighted the possibility of using these EOs in the termite control for the preservation of wooden structures

Indagini sulle infestazioni di Aphis gossypii Glover su melone invernale (Cucumis melo Var. Helios) in aziende a conduzione biologica della Sicilia occidentale.

Investigations on the aphid infestation occurring on winter melon crops (Cucumis melo var. Helios) in organic farms of western Sicily The winter melon (Cucumis melo L.) is an important crop in Sicily. Previous studies carried out in western Sicily have shown that the aphid species Aphis gossipii is the key pest of winter melon crops.A. gossypii is a cosmopolitan species with very polyphagous habits; this phytophagous insect is capable of serious economic damage due to direct feeding of the sap plant and due to the honeydew secretion and the consequent presence of sooty mold and due to the possible transmission of viruses. The aim of this work was to investigate the levels of aphid infestation in two different organic winter melon fields located in western Sicily by monitoring the dynamic of population of A. gossypii and the complex of natural enemies associated with the pest. In addition the possible influence of mulching as aphid repellent has been evaluated. In one location we monitored the aphid infestation through direct observation of the plants that have been carried out weekly from transplant to harvest of the product. In the other location, we investigated the dynamics of population and levels of adult infestation, evaluating also the possible influence of mulching, using chromotropic traps, consisting in yellow adhesive plates placed horizontally in mulched rows, on the plastic film, and alleyways, on the ground. In addition, surveys were carried out by comparing mulched plots and not mulched plots. Our results showed that, in both locations, the population density of A. gossypii was low and no serious damage has been inflicted to the crop: this is probably related to the abundant presence of natural enemies of the pest and to the repellent action of mulching

Indagine su Raphidopalpa foveicollis (Lucas) nella coltura del melone biologico della Sicilia occidentale.

Investigations on Raphidopalpa foveicollis (Lucas) in an organic cultivation of winter melon in western Sicily Red pumpkin beetle (Raphidopalpa foveicollis), is a Chrysomelidae beetle that lives on various species of cucurbits with greater preference for Cucumis sp. Both larval and adult stages are injurious to the crops. The former feeds on roots and stems of the plants, while the latter feeds on foliage, petals and fruits. In Sicily, this insect has occurred in the past as a secondary pest on the winter melon, but sometimes it reaches levels of infestation to arouse considerable concern among farmers. In order to implement economic methods of pest control a study on organic cultivation of winter melon was conducted in Camporeale (500 meters a.s.l.) (Palermo). Particularly, the dynamics of population and infestation levels have been investigated, taking into account also the possible influence of mulching, using chromotropic traps. Such traps consisted of yellow adhesive plates placed horizontally in mulched rows, on the plastic film, and between the rows, on the ground. In addition, surveys were carried out by comparing mulched plots and not mulched ones. Results showed that the peak catches (47.4 adults / trap) occurred in mid-June and the greater number of catches was found in the traps placed between the rows, with significant difference. A greater number of individuals has been detected on plants of the not mulched plots than that of the mulched plots, even though no statistically significant difference was found. The percentage of plants with damaged leaves ranged from 68.7% to 100% on mulched plots and 93.3% to 100% on not mulched plots with no significant differences. The presence of adults has also been observed on fruits but without signs of trophic activity. In addition, young stages were not detected in the plants examined. In conclusion, the combined effect of mulching, at least until the vegetation does not cover the plastic film, and sticky traps, placed mostly between the rows, plays a synergistic action to the pest control. Considering the low cost of such technique, it may be a potential tool for managing this pest using mass trapping method

Indagine su Henosepilachna elaterii (Rossi) (=Epilachna chrysomelina (F.)) e Raphidopalpa foveicollis (Lucas) in meloneti biologici della Sicilia occidentale.

Investigations on Henosepilachna elaterii (Rossi) and Raphidopalpa foveicollis (Lucas) in an organic cultivation of winter melon in western Sicily. A study on H. elaterii and R. Foveicollis, serious pests of winter melon, was conducted in two organic melon fields of the western Sicily. Dynamics of population and infestation levels were investigated. In addition, the possible influence of mulching on R. Foveicollis infestation has been taken into account. Our results showed that H. elaterii occurred only in one field from the beginning of June and it infested 60% of the plants in the mid-July, then the pest population density dropped to about 10%. R. foveicollis occurred in both locations from the beginning of June and reached high levels of population density around the mid-June; then the pest density rapidly decreased in the two following weeks. Adults were found in the traps and the peak catches occurred in mid-June. A greater number of catches was found in the traps placed between the rows and the greater number of individuals has been detected on plants of the not mulched plots. The percentage of plants with damaged leaves ranged from 68.7% to 100% on mulched plots and 93.3% to 100% on not mulched plots. In conclusion, the damages inflicted by R. foveicollis are counterbalanced by the rapid growing rate of the plant occurring during June. Hence, this pest may cause serious injuries only in case of heavy infestation on winter melon seedlings. Similarly, the damage caused by H. elaterii is usually not heavy even if presence of high levels of infestation

Indagini sulla presenza di Prays oleae in oliveti a conduzione biologica della Sicilia occidentale

Investigations on presence of Prays oleae in organic olive orchards of western Sicily. This paper reports a study on the population dynamics of the olive moth, Prays oleae (Bern) (Lep., Plutellidae) in four organic olive orchards in western Sicily (Italy), from 2007 to 2010. The influence of the phytophagous on the fruit drop was detected. Also, the efficacy of treatments with Bacillus thuringiensis var. kurstaki on damage reduction was evaluated. Flight trend was monitored using delta-wing traps (3/ha) containing the sexual pheromone ((Z)-7-tetradecenal), placed in each olive orchard. Traps were hung in the inner zone of the canopy to a height of 1.50 m, and checked weekly from May to 2-3 days after the olive harvest. Capture data indicated that flight peaks occurred on June-July and September-October. In 2007, the population density of P. oleae moths was generally lower than the subsequent three years . The fruit infestation levels in all years were under 5% and a greater susceptibility of Biancolilla and Cerasuola var. than Nocellara var. were detected. In 2008, the fruit drop caused by P. oleae ranged from 12% to 47% in two orchards studied. Finally, the results for two years indicate that treatments with Bacillus thuringiensis (Bt) can significantly reduce the fruit fall caused by phytophagous in comparison with untreated olive orchards

Dinamica di popolazione di Aphis gossypii possibile vettore del Virus della Tristeza in un agrumeto della Sicilia occidentale

Tra le specie di afidi che attaccano gli agrumi in Sicilia, Aphis spiraecola Patch, Toxoptera aurantii (B.d.F) e Aphis gossypii Glover rivestono importanza economica, essendo presenti dalla primavera all’autunno con livelli di infestazione molto alti. Oltre ai danni legati all’attività trofica, tutte e tre le specie primarie, sono in grado di trasmettere il virus della Tristeza (CTV); in bibliografia l’efficienza è considerata alta nel caso di A. gossypii e poco rilevante nel caso delle altre due specie. La trasmissibilità del CTV, oltre che dalla specie vettrice, dipende da diversi fattori quali, le specie di Citrus donatrici o recettrici, la virulenza dell'isolato del virus, il comportamento alimentare, riproduttivo e di diffusione del vettore. Nell’ambito del progetto “Lotta al virus della Tristeza sviluppo e innovazioni” finanziato dalla Regione Siciliana si è voluto monitorare la presenza A. gossypii e valutare i livelli di infestazione in un agrumeto a conduzione biologica sito nel territorio di Castelvetrano (TP) da maggio del 2012 fino a settembre 2013. Su 20 piante di arancio varietà Navel, scelte a caso su un appezzamento di circa un ettaro, per i quattro punti cardinali, è stata rilevata la percentuale di germogli infestati su una superficie di chioma di 0,25 mq. Inoltre, campioni di A. gossypii sono stati prelevati e sottoposti ad analisi per appurare la presenza del virus. Le osservazioni hanno mostrato che, in entrambi gli anni, l’infestazione di A. gossypii è iniziata alla fine di aprile, ha raggiunto i massimi livelli tra metà maggio e inizio giugno, scomparendo verso la metà del mese di giugno. Per riprendere nel periodo autunnale. Nel 2013 l’infestazione è ripresa nella seconda decade di luglio in concomitanza alla emissione di nuovi getti vegetativi conseguenti ad una irrigazione, con valori paragonabili a quelli primaverili. Le differenze delle percentuali di infestazione rilevate ai quattro punti cardinali non sono statisticamente significative. I campioni sottoposti ad analisi sono tutti risultati esenti da virus