247 research outputs found
A step out of the lab: the importance of formulations in the development of biopesticides
No full textDeveloping microbial-based biopesticides represents a promising eco-friendly strategy for the sustainable management of plant pathogens. However, the use of microbial biocontrol agents (mBCAs) as biopesticides is often limited, mainly due to the vulnerability of the microorganisms to environmental factors and microbial competition, and the difficulty in developing a formulation that preserves efficacy and viability of mBCAs during storage and application. This chapter reports the current state of biocontrol strategies and describes the latest approaches to attain more effective formulations. Emphasis is placed on techniques and tools available for optimizing fermentation and formulation processes and enhancing the stability of mBCAs in the environment. Special attention is also given to the use of multi-strain formulations and their usefulness as plant protection products. Finally, innovative application approaches are described
Microbial biocontrol agents: developing effective biopesticides
No full textThe negative impact of chemical pesticides on human wellbeing and the environment has encouraged the development of eco-friendly alternatives for the management of plant pathogens. However, only a small number of microbial biocontrol agents (mBCAs) have been developed, registered and used in the management of plant diseases. This book analyses the deployment of mBCAs for the development of novel microbial biopesticides, considering the main plant-beneficial traits, procedures needed for effective formulations and the processes used for their validation. To guide the readers through the world of microbial biopesticides, the book starts with a chapter dedicated to the regulations that need to be followed for the development of final products. Readers will understand the importance of formulation and mode of action of mBCAs in developing microbial biopesticides. They will become familiar with key mBCAs such as Ampelomyces quisqualis, Bacillus spp., Trichoderma spp., and Pseudomonas spp., understanding the importance of formulation for their application in the field. This book explains the use of mBCAs to control post-harvest diseases and the potential of endophytic microorganisms as next-generation microbial biopesticides. A final chapter provides a useful workflow for the selection of new mBCAs and describes microbial species including promising mBCAs that might be developed as new microbial biopesticide
Biological control of Plasmopara viticola: where are we now?
No full textGrapevine downy mildew, caused by Plasmopara viticola, is one of the most critical diseases on grapevine worldwide, causing relevant economic losses. Nowadays, the management of grapevine downy mildew relies mainly on the application of copper and synthetic fungicides. However, due to the occurrence of P. viticola populations resistant to fungicides and the impact of chemicals on humans and the environment, the development of eco-friendly plant protection products is highly requested. Biocontrol agents are effective in controlling P. viticola on grapevine and represent an important alternative to the use of synthetic fungicides and copper in viticulture. Several bacterial and fungal biocontrol agents have been evaluated for their ability to directly control P. viticola or by stimulating defense mechanisms in grapevine plants. In the future, the progressive reduction of the chemical input in viticulture and the current lack of commercial microbial biopesticides active against P. viticola will make the management of grapevine downy mildew a compelling challenge in the field of biological control of plant disease
Portfolio Selection with Transaction Costs and Default Risk
No full textPurpose: The purpose of this paper is to investigate the effect of default risk and transaction costs on the investor's asset allocation and the liquidity premium. More precisely, it aims at answering the following question: can default risk generate a first-order effect on the investor's asset allocation and a liquidity premium of the same order of magnitude as transaction costs?
Design/methodology/approach: The author proposes a very simple consumption-investment model in which an infinitely-lived investor allocates her wealth between a risky asset and a riskless security, and incurs in proportional transaction costs when exchanging them. In addition, the risky asset
may default at some random time, thus reducing the available wealth of the agent. Two different scenarios of default risk are considered. In the total default scenario, the value of the risky asset drops to zero when default occurs whereas, in the partial default case, the proceeds from the liquidation of the risky asset amount to 50% of its value.
Findings: The paper shows that default risk can generate a first-order effect on the investor's asset allocation. On the contrary, the liquidity premium is one order of magnitude smaller than the transaction costs, implying that the additional source of risk determined by the possibility of default is not able to generate a first-order effect on asset pricing.
Originality/value: To the author knowledge, this is the first paper that investigates the interaction of default risk and transaction costs on the investor's asset allocation and its effects on the liquidity premium
Key impact of an uncommon plasmid on bacillus amyloliquefaciens subsp. plantarum S499 developmental traits and lipopeptide production
No full textpeer reviewedThe rhizobacterium Bacillus amyloliquefaciens subsp. plantarum S499 (S499) is particularly efficient in terms of the production of cyclic lipopeptides, which are responsible for the high level of plant disease protection provided by this strain. Sequencing of the S499 genome has highlighted genetic differences and similarities with the closely related rhizobacterium B. amyloliquefaciens subsp. plantarum FZB42 (FZB42). More specifically, a rare 8008 bp plasmid (pS499) harboring a rap-phr cassette constitutes a major distinctive element between S499 and FZB42. By curing this plasmid, we demonstrated that its presence is crucial for preserving the typical physiology of S499 cells. Indeed, the growth rate and extracellular proteolytic activity were significantly affected in the cured strain (S499 P-). Furthermore, pS499 made a significant contribution to the regulation of cyclic lipopeptide production. Surfactins and fengycins were produced in higher quantities by S499 P-, whereas lower amounts of iturins were detected. In line with the increase in surfactin release, bacterial motility improved after curing, whereas the ability to form biofilm was reduced in vitro. The antagonistic effect against phytopathogenic fungi was also limited for S499 P-, most probably due to the reduction of iturin production. With the exception of this last aspect, S499 P- behavior fell between that of S499 and FZB42, suggesting a role for the plasmid in shaping some of the phenotypic differences observed in the two strains. © 2017 Molinatto, Franzil, Steels, Puopolo, Pertot and Ongena
The biocontrol agent Pseudomonas chlororaphis subsp. aureofaciens M71 originates natural mutants impaired in the ability to control Fusarium oxysporum f. sp. radicis-lycopersici on tomato
No full textPseudomonas chlororaphis subsp. aureofaciens M71 differentiated three natural mutants distinguishable for morphological traits. P. chlororaphis subsp. aureofaciens M71 mutants were impaired in persisting on tomato roots and controlling tomato crown rot. Mutants were characterised by a reduced ability in production of autoinducer signals and antibiotic
Pseudomonas chlororaphis metabolites as biocontrol promoters of plant health and improved crop yield
No full textThe Pseudomonas fluorescens complex contains at least eight phylogenetic groups and each of these includes several bacterial species sharing ecological and physiological traits. Pseudomonas chlororaphis classified in a separate group is represented by three different subspecies that show distinctive traits exploitable for phytostimulation and biocontrol of phytopathogens. The high level of microbial competitiveness in soil as well as the effectiveness in controlling several plant pathogens and pests can be related to the P. chlororaphis ability to implement different stimulating and toxic mechanisms in its interaction with plants and the other micro- and macroorganisms. Pseudomonas chlororaphis strains produce antibiotics, such as phenazines, pyrrolnitrine, 2-hexyl, 5-propyl resorcinol and hydrogen cyanide, siderophores such as pyoverdine and achromobactine and a complex blend of volatile organic compounds (VOCs) that effectively contribute to the control of several plant pathogens, nematodes and insects. Phenazines and some VOCs are also involved in the induction of systemic resistance in plants. This complex set of beneficial strategies explains the high increasing interest in P. chlororaphis for commercial and biotechnological applications. The aim of this review is to highlight the role of the different mechanisms involved in the biocontrol activity of P. chlororaphis strains
This tree is on fire: a review on the ecology of Erwinia amylovora, the causal agent of fire blight disease
No full textFire blight represents a great threat to apple and pear production worldwide. The ability of its causal agent, Erwinia amylovora, to spread rapidly in the host plants makes this devastating disease difficult to manage. Copper and antibiotics are still the most effective solutions to control fire blight, although their application contribute to environmental pollution and to the development of E. amylovora resistant populations. Thus, there is an urgent need to find new alternatives to such plant protection products. In this review, we summarized what is known on E. amylovora biology, as the knowledge of the plant pathogen biology is essential to develop eco-friendly management strategies. Notably, the presence of E. amylovora alone does not necessarily result in the disease development as it is the final outcome of multiple interactions established between E. amylovora cells, flower microbiota, plant host, insect vectors and environment. For instance, specific humidity and temperature create the suitable conditions for E. amylovora to grow and reach the specific cell density needed for plant infection. Once fire blight develops, insects act as potential vectors of E. amylovora, playing a role in the dispersal of the disease. The host plant represents an important factor as its susceptibility varies among the species belonging to the Rosaceae family. Recent studies showed apple flower microbiota might promote or hinder the infection progress, thus representing a possible source of new biocontrol agents effective in controlling E. amylovor
Lending quality and contracts enforcement reforms
No full textWe investigate the causal relationship between the efficiency of country's judicial system and the quality of bank lending, using the contracts enforcement reforms implemented in four European countries as a quasi‐natural experiment. We find that strengthening contracts enforcement determines large, significant and persistent reductions in banks' nonperforming loans. Our results have important policy implications: they
point at judicial efficiency as a critical determinant of the stability of the banking sector and its resilience to adverse shocks such as the recent Covid‐19 pandemic
Identification and characterization of Lysobacter capsici strain PG4: a new plant health promoting rhizobacterium.
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