6,543 research outputs found
Use of biocontrol agents in combination with physical and chemical treatments: efficacy assessment
No full textPurpose of review: This review discusses the combination of biological control agents with physical (heat, gamma or UV-C
irradiation, controlled atmosphere) or chemical (salt additives, chitosan, natural plant products) treatments against the main
postharvest fruit diseases.
Findings: The use of biocontrol agents (BCAs) to control postharvest fruit diseases is still constrained by the lack of high levels
of disease control required in the postharvest phase (more than 95%). Their inconsistent activity is one of the main factors preventing
their routine application on fruit after harvest. Therefore, to overcome this issue, integrated strategies were explored
and continue to be one of the fields most investigated in postharvest fruit disease control, in order to achieve maximum effectiveness.
The combination of BCAs with physical and chemical treatments, including fungicides at low doses, resulted in an
increase of BCAs effectiveness against fungal diseases such as Pencillium spp., Monilinia spp., Botrytis cinerea, etc. Since the
integration of different treatments could benefit from their additive or synergic effects and improve the efficacy of each single
method.
Limitations: It is unrealistic to assume that BCAs have the same fungicidal activity as pesticides; the evaluation of their compatibility
with other methods therefore seems to be the main topic that will be developed in the near future. Nevertheless, it is
necessary to evaluate the possible detrimental effects of some treatments like gamma irradiation or essential oils on qualitative
fruit parameters in view of their commercial application. In addition, the use of low doses of fungicides cannot be applied to
organic production.
Directions for further research: Specific appropriate strategies have to be evaluated for each species and pathogen in order to
tailor a complete integrated disease management. Moreover, these integrated applications have to be investigated at commercial
levels, including during fruit handling, in order to ascertain their practical efficacy
Monilinia fructicol, Monilinia laxa (Monilinia Rot, Brown Rot)
No full textMonilinia spp. causing brown rot is a fungal pathogen producing severe losses in worldwide stone fruit production, with high economic relevance (M€ 1.7/year). There are three main fungal species: Monilinia laxa, M. fructigena and M. fructicola. The pathogen infects aerial parts of host plants with a variety of symptoms, including blighting of blossoms, cankers on woody tissues and rotting of fruits, although the prevalent fruit losses are in the postharvest phase. Fungicide sprays in pre and postharvest periods are usually used to control Monilinia spp., but in Europe no fungicide fruit treatments are allowed after harvest. Many studies conducted in recent years have defined three main research fields within the alternative methods for postharvest brown rot control: i) biological control sensu strictum with microbial antagonists, ii) use of natural bioactive compounds and iii) use of physico-chemical methods. Although the reviewed results have reported a significant reduction of pesticide use, recommend a multidisciplinary approach in the future, where biological products will be combined with low risk chemical fungicides, natural antimicrobial substances and other physical means for an integrated strategy to control brown rot
New Strategies to Control Brown Rot Caused by Monilinia spp. of Stone Fruit
No full textThe importance of brown rot caused by Monilinia spp. in all stone fruit growing areas is well recognized. The infection occurs in the field but the most dangerous fruit losses happen during storage and commercialization. The disease control depends mainly on integrated strategy based on cultural practices and fungicide spray programmes in the field. Among cultural practices, the sanitization of orchard by minimizing inoculum potential, reducing the risk of blossom and fruit infections is essential for brown rot management. However, the requirements in sustainable agriculture, integrated crop management and organic production are increased in the last few decades, resulting in the need to develop other methods than fungicide applications to disease control. Several studies focused on alternative strategies, defining three different approaches: i) biological control with microbial antagonists, ii) use of natural products and iii) use of physico-chemical methods. Significant progress has been achieved in the reduction of pesticide use with these methods; although a multidisciplinary methodology that integrates sanitary and alternative strategies has to be investigated more fully. The new strategy, starting from the field with agronomic interventions and the selection of cultivars tolerant to Monilinia spp. could be usefully integrated by postharvest treatments based on low risk chemical fungicides, natural antimicrobial substances and other physical means determining a sustainable approach to brown rot control
New strategies to control brown rot caused by Monilinia spp. of stone fruit
No full textThe importance of brown rot caused by Monilinia spp. in all stone fruit growing areas is well recognized. The infection occurs in the field but the most dangerous fruit losses happen during storage and commercialization. The disease control depends mainly on integrated strategy based on cultural practices and fungicide spray programmes in the field. Among cultural practices, the sanitization of orchard by minimizing inoculum potential, reducing the risk of blossom and fruit infections is essential for brown rot management. However, the requirements in sustainable agriculture, integrated crop management and organic production are increased in the last few decades, resulting in the need to develop other methods than fungicide applications to disease control. Several studies focused on alternative strategies, defining three different approaches: i) biological control with microbial antagonists, ii) use of natural products and iii) use of physico-chemical methods. Significant progress has been achieved in the reduction of pesticide use with these methods; although a multidisciplinary methodology that integrates sanitary and alternative strategies has to be investigated more fully. The new strategy, starting from the field with agronomic interventions and the selection of cultivars tolerant to Monilinia spp. could be usefully integrated by postharvest treatments based on low risk chemical fungicides, natural antimicrobial substances and other physical means determining a sustainable approach to brown rot control
Decay control in the postharvest system: Role of microbial and plant volatile organic compounds
No full textSignificant postharvest losses occur during the supply chain of fresh produce. Postharvest decay is one of the main factors that determines losses and compromises the quality of fruit and vegetables. Traditionally postharvest decay control is achieved using chemical fungicides; however, the important concerns relating to environmental and human health require the development of novel methods for the control of postharvest decay. Furthermore, the consumer demand and the purchasing power are higher for fresh produce that are free from pesticide application. This review highlights the research literature based information on the application of microbial and plant volatile organic compounds (VOCs) to control postharvest decay, their practical applications in postharvest systems and the future perspectives. The volatile nature of VOCs could be potentially employed with success as gaseous
treatments in a process defined ‘biofumigation’. Plant-produced volatiles including among others, aldehydes such as acetaldehyde, 2-E-hexenal and benzaldehyde, alcohols such as ethanol and acetic acid, essential oils (EOs) and isothiocyanates (ITCs) and microbial volatile organic compounds have been recognised as potential substances in preventing pathogenic infections in many horticultural commodities. However, some issues have to be well elucidated in order to admit these substances in a large-scale application to improve the competitiveness of the fresh produce at the quality stringent EU, USA, and the Japanese markets. The main concern are related to the registration process, but also VOCs
degradation and residues in fruit, formulation and organoleptic impact, are aspects that have to be thoroughly considered prior to commercialisation of the selected VOC. Furthermore, VOCs could have an effective role for an eco-chemical approach in postharvest disease control since these biobased products, if compared to conventional ones, can offer clear environmental benefits due to their renewability, biodegradability and hypotoxicity
Alternative technologies to control postharvest diseases of kiwifruit
No full textThe review deals with alternative technologies to conventional synthetic fungicides to control
kiwifruit postharvest diseases. Prolonged and intensive use of these fungicides raises concerns regarding the safety of their residues in fruit and has caused the emergence of fungicide resistant pathogen strains. Alternative treatments were investigated, such as hot water, biological control agents (BCAs), and natural substances. Kiwifruit production is economically important in many parts of the world, but little is known about
means of controlling its postharvest diseases. Many fungi cause postharvest rot of kiwifruit, and their occurrence varies among the production areas. Ripe-rot caused by Botryosphaeria dothidea and stem-end rot caused by Diaporthe actinidiae prevail in New Zealand, while stem-end rot caused by Botrytis cinerea is the most important postharvest disease of the kiwifruit cultivated in Europe and USA, while in these regions skin pitting by Cadophora luteo-olivacea
and Mucor rot caused by Mucor piriformis are less important. In terms of control technique, curing, which is a delay between harvesting and cool storage of fruit, remains an important and safe tool to reduce postharvest losses, but improvements in it are needed. Innovative non-chemical treatments include hot water dipping (45°C for 10 min) for controlling several diseases which has received commercial attention. The application of BCA following curing
for 96 h was demonstrated to be effective against B. cinerea. Some natural compounds controlled grey mould well in artificially and naturally infected fruit
Preliminary studies on partial reduction of Colletotrichum acutatum infection by proteinase inhibitors extarcted from apple skin
No full textColletotrichum acutatum, a fungal pathogen that causes soft rot in fruit, produced protease when grown
on casein or apple cell wall, as revealed by a clear zone around the well filled with C. acutatum medium in
a radial diffusion assay. A protease-inhibiting protein (PI) was also extracted from healthy stored apple,
cultivar Cripps Pink, and its activity was tested in vitro and in vivo against a protease produced by
C. acutatum. In in vitro trials the inhibition rate determined by radial diffusion assay was over 41% after
24 h, while in inoculated fruit the inhibition ranged from 23.5% to 45% after 5 days at 20 C. The protease
inhibitor extracted from healthy apple skin was a heat-denaturable protein since the halo produced by
protein extracted from C. acutatum and added to boiled protein extracted from healthy apple skin tissue
was 338.7 mm2, significantly higher than the halo produced by protein extracted from C. acutatum
diluted with fresh protein extracted from healthy tissue (220.7 mm2). Protein secreted by C. acutatum
grown in induced buffer media was tested by polyacrylamide gel electrophoresis. SDS-PAGE of crude
enzyme extract revealed the presence of various protein bands that could be ascribed by their molecular
mass as putative aspartic proteinase, extracellular alkaline proteinase and serine protease. Genomic
analyses are, however, in progress to identify the proteins involved in Colletotrichum patogenicity. More
investigations are required to identify the nature of the substance responsible for C. acutatum inhibition
in apple and to evaluate the possibility of manipulating the protease inhibitor levels in fruit to reduce soft
rot caused by C. acutatum
Un radioso avvenire? L’impatto della Rivoluzione d’ottobre sulle scienze umane
No full textÈ impossibile analizzare il 1917 se non con uno sguardo che catturi l’eterogeneità dell’impatto rivoluzionario e generi una riflessione critica sulle sue rifrazioni a breve e lungo termine. La prospettiva storiografica, in questo volume, muove inevitabilmente dall’ampiezza continentale dell’evento, lampante fin dai primi anni postrivoluzionari, per poi concentrarsi sulla ricezione specifica dei fatti e le ripercussioni oltrefrontiera, tra speranze tradite e stravolgimento di ogni aspetto del quotidiano, spazi urbani e geografici compresi. Chiaro riflesso dei sentimenti e delle disillusioni dell’Ottobre, la letteratura guarda al presente con occhio critico e al futuro con disincanto e rassegnazione, cedendo a derive oniriche e distopiche, mentre l’arte visiva attende e poi celebra come realizzata l’utopia. È un contagio senza fine quello della Rivoluzione, che come un torrente travolge tutto e si scompone in piccoli rivoli che impregnano ogni aspetto della vita quotidiana, moda, arte teatrale e balletto, in un incessante lavoro di scambio culturale, ideologico, letterario, critico e politico che la Russia postrivoluzionaria intrattiene con i suoi interlocutori stranieri, europei fino ai giorni nostri. A cent’anni esatti da quell’Ottobre
Palladium- or nickel-catalyzed sequential reaction of organic bromides, bicyclo [2.2.1]hept-2-ene or bicyclo[2.2.1]hepta-2,5-diene and alkynes
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