Green Synthesis of Nanomaterials

Nanomaterials possess astonishing physical and chemical properties. They play a key role in the development of novel and effective drugs, catalysts, sensors, and pesticides, to cite just a few examples. Notably, the synthesis of nanomaterials is usually achieved with chemical and physical methods needing the use of extremely toxic chemicals or high-energy inputs. To move towards more eco-friendly processes, researchers have recently focused on so-called “green synthesis”, where microbial, animal-, and plant-borne compounds can be used as cheap reducing and stabilizing agents to fabricate nanomaterials. Green synthesis routes are cheap, environmentally sustainable, and can lead to the fabrication of nano-objects with controlled sizes and shapes—two key features determining their bioactivity

Spread of Zika virus: The key role of mosquito vector control

Mosquitoes (Diptera: Culicidae) represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above, it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nanoparticles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation (i.e. the "lure and kill" approach), pheromone traps, sound traps need further research attention. In particular, detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required

Plant-mediated synthesis of nanoparticles: A newer and safer tool against mosquito-borne diseases?

Abstract Prevention and control of mosquito-borne diseases is a key challenge of huge public health importance. Plant-mediated synthesis of nanoparticles has recently gained attention as a cheap, rapid and eco-friendly method to control mosquito vector populations, with special reference to young instars. Furthermore, plant-fabricated nanoparticles have been successfully employed as dengue virus growth inhibitors. In this Editorial, parasitologists, entomologists and researchers in drug nanosynthesis are encouraged to deal with a number of crucial challenges of public health importance

Food for honeybees? Pollinators and seed set of Anthyllis barba-jovis L. (Fabaceae) in arid coastal areas of the Mediterranean basin

Abundance and diversity of insect pollinators are declining in many ecosystems worldwide. The abundance and diversity of wild and managed bees are related to the availability of continuous floral resources. In particular, in Mediterranean basin countries, the presence of wildflower spots enhances the establishment of social Apoidea, since coastal regions are usually characterized by pollen and nectar shortage in early spring and late summer. Anthyllis barba-jovis produces both nectar and pollen as important food source for bees helping them to overcome early spring period food shortage. We investigated flowering, seed set, and pollinator diversity of A. barba-jovis in arid coastal environments of the Mediterranean basin. Pollinator abundance reached a maximum in early April. Honeybees were the most common pollinators followed by bumblebees and solitary bees. Plants prevented from entomophilous pollination showed inbreeding depression with a strong decrease in seed-set. To the best of our knowledge, this is the first report on pollination ecology of A. barba-jovis

Protecting crop species from biotic and abiotic constraints in the era of global change: Are we ready for this challenge?

Reliable andaffordable supply of food is of crucial importance to the progress andstability of human societies. During the last century, we have assisted to anextraordinary increase of crop yields, especially for the most widespread andconsumed crop species, such as rice, wheat, corn and soybean. The Broadbalkexperiment, one of the oldest continuous agronomic experiments in the world,have showed how half of the increase of crop productivity is mainly due to the improvementsintroduced through plant breeding and half through to agronomical practices,although both are dependent on each other (Rasmussen et al., 1998). The development of a huge numbers of scientificplant breeding programs has been of vital relevance in improving crop varietiesand productivity. In addition, collection and spread of improved germplasmaround the world have ensured that all breeders could quickly benefit from theadvances obtained by others. On the other side, based on Lawes and Gilbert'swork in the previous century, the main advances in agronomy consisted on thecontinued use of fertilizers, the true value of which could only be realized inthe presence of suitable varieties and in the absence (or under controlledpressure) of competition from weeds, pest and diseases. Therefore, cropprotection became crucial and it was achieved by the improvements of theagrochemical industry, which has developed sophisticated, high-targeting andmore efficient agrochemicals. Taken together, the use of new high-yieldvarieties in association with chemical fertilizers and agrochemicals,controlled water-supply (irrigation), and new methods of cultivation, includingmechanization, are commonly identified under the term “Green Revolution” which wasconied between ’30 and ’60 and was responsible in some cases for doubling (oreven triplicating) the agricultural production for many crops species, inparticular cereals. The incremented crop productivity hasbrought many social gains, such as reducing the malnutrition, lowering foodprice, increasing food security. Moreover, since the economic sustainability isthe most important factor for the adoption of a crop for farmers (Sgroi et al., 2014; Testa et al., 2015), the increased crop productivity occurred in the lastdecades, has determined a positive impact on the development of several ruralareas. The increase of cropyield, has caused, on the other side, large changes in rural societies due tothe migration of population from the countryside (caused by the decrease ofmanpower needs) to towns and cities where the industrialization offered moreopportunities. The better living conditions lead to the highest increment ofword population that has ever been documented: from 2.5 b people to 5.2 b in 40years (1950-1990; UNR, 2004). Nowadays, word population is predicted toincrease from 7.4 b people (May, 2016), to 8.4 b in 2030 and 9.5 b in 2050 (U.SCensus Bureau). In addition, people rise out of poverty, higher livingstandards, such as greater meat consumption, and personal mobility will increaseeven more the demand on food production (and quality), animal feed, fiber, andfuels. Thus feeding, clothing and fueling a more densely populated planet isprobably the key challenge of our century. Industrializationand anthropic activities have also imposed profound alterations to theenvironment and, decade after decade, have contributed to alter dramaticallythe life conditions on Earth leading to the so called “Global Change” (alsoreferred as “Global Warming” or “Climate Change”), phenomenon from which we areactually trying to run for cover. Based on several reports produced by theIntergovernmental Panel on Climate Change, it emerges as the most hazardouseffects of Global Change, such as rising temperatures and heat waves, prolongedperiods of drought, and incremented levels of pollutants in all the compartmentsof biosphere can cause more frequent and severe fluctuations in cropproductivity, but also can seriously threaten the availability of arable land;for example increasing the amplitude of soil/water salinization or soilerosion. The total surface of arable soil is also undermined by the constantrequirement of lands for human activities that, beyond the direct effect ofoverbuilding, in many cases also increase the pollution of surrounding areas, forexample through the release of heavy metals, hydrocarbons, xenobiotics or otherpollutants in soil, water, and/or in the atmosphere. Global Change alsoinfluences the ecology of weeds, pests and disease, with possible implicationsfor crop protection and pesticide use. The ability of science to makepredictions on the impact of Global Change on ecosystem interactions is limitedbecause models that include multiple interactive effects of Global Change arestill relatively rare and the comprehension of results obtained from modelsystems results quite complicated. For this reason, despite the scientificcommunity concords on the dramatic impact of Global Change on cropproductivity, predictions may have sometimes-different facets depending on theinformation source. Some researchers reported however that in the time span1981-2001, changes in precipitation and increased temperatures have already inducedannual losses of wheat, maize and barley production of about 40 million tons peryear (Lobell and Field, 2007). Thus, beyond future prediction(s) of GlobalChange effect, humanity is still experiencing the effects this phenomenon forat least three decades. It is evident that in a near future akey challenge for humanity is to increase the productivity of crop specieswhile decreasing water supply, the use of fossil fuels, chemical fertilizer,pesticides (and more in general agrochemicals), and other negativeenvironmental inputs. On the other side, less clear is how agriculture’s outputcan increase so substantially without significantly increasing itsenvironmental footprint. Plant physiologyand biochemistry have developed as powerful disciplines during the 20thcentury, but only in a few cases they have led to relevant crop improvement,and in any case, nothing as compared to the amazing gains on crop productivityobtained through the classical genetic breeding from 1930 to 1960. This islikely because the links between the biochemistry and genetics of the processesdescribed were not established, but rather high-yield genotypes were selectedonly for this desired feature lacking to explore the reason on the bases ofthis gain. The situation has changed after the discovery of the DNA structureby Watson and Crick (1953) and even more after ’70, when the first positiveresults with transgenic plants were obtained. From that time onward, theability to control one or few genes has also deepened the knowledge on the biochemicalmechanisms underlying the genetic process that has been modified. This newapproach, associated with the rapid development of “omic” sciences, has thepotentiality to lead to significant advances either in crop yield, quality,and/or plant protection in a near future. The future need for higher cropproductivity must parallel with a reduction of agronomical inputs as in thepast high-yield genotypes have been selected for their performances with highinputs, especially fertilizers and pesticides. Agricultural emissions from cropand livestock production grew from 4.7 billion tons of carbon dioxideequivalents (CO2 eq) in 2001 to over 5.3 billion tons in 2011. Inthe same period, annual emissions from fertilizers increased by 37% and in 2011the world total annual emissions fromsynthetic fertilizers averaged 725 Mt CO2 eq, about 14% of total emissionsfrom agriculture in the same year (Tubiello etal., 2014). Advances in the basic knowledge of plant genetic, physiologyand biochemistry should thereby be address to increase the efficiency of inpututilization by plants in order to reduce the input level. Technologicaladvances on instrumentations, such as precision farming tools (such as GPStracking devices designed for farming), as well as agronomical practices (i.e.advanced organic farming, eco-friendly soil amendments) can also significant contributeto achieve this goal. The extensiveemploy of synthetic pesticides against pests of agricultural and veterinaryimportance, especially in developing countries, lead to important concerns forhuman health and the environment (Desneux etal., 2007; Hemingway and Ranson, 2000; Naqqash et al., 2016). In this scenario, the need for effective and eco-friendlycontrol tools has gained increasing attention in latest years (Benelli, 2015;2016). Besides this, a further challenge for crop and livestock protectionnowadays, is the improvement of the success of biological control programs,developing effective quarantine procedures and proper evaluation of thenon-target effects of biocontrol agents (Hajek et al., 2016). Furthermore, chemoecological knowledgeabout pests and biocontrol agents may represent a valid help to improve integratedpest management strategies. Indeed, foraging kairomones exploited bycarnivorous arthropods have been successfully tested as field lures to attractcarnivores in damaged agricultural habitats. However, practical applications offoraging kairomones seem to be restricted by major concerns including carnivorousarthropod habituation, carnivorous arthropod time-wasting on victim-free crops,exploitation of host-borne cues by hyperparasitoids and lack of foraging kairomones specificity due totri-trophic interactions sharing a given habitat that use identical chemicalsignals, thus confounding species-specific biological control agents (Kaplan,2012). Further research on new applications of physical and chemical signalsexploited by carnivorous arthropods is urgently required. Physical andolfactory cues can be used to experience mass-reared predators and parasitoids,via sensitization or associative learning practices (Giunti et al., 2016). This could help toovercome critical steps in mass rearing of biocontrol organisms and improvebeneficial performances of carnivorous arthropods in the field. In view of the growing scientificinterest on the effects of Global Changes factors on the relationship betweenplant-pest-environment, in this issue a collection of papers focused on thistopic are presented. Beyond awareness of the deleterious impact of GlobalChange, factor which should lead humanity to a wiser use Earth’s resources, we believethat only the in-depth comprehension of mechanisms adopted by crop species toendurance under stress (Landi et al.,2012; 2013; 2014; 2015; Pardossi et al.,2015; Penella et al., 2016; Tattini et al.,2014) associated with new eco-friendly methods to control crop pests anddiseases may represent a way to contrast the effect of Global Change meanwhilewe are attempting to increase crop productivity for supporting the needs of anincreasingly crowded planet

Insecticidal Activity of Plant Secondary Metabolites

Dear Colleagues, Plant secondary metabolites display a plethora of biological functions, among which the biochemical defense against insects and other organisms is one of the most important ones. For this purpose, they synthesize alkaloids, terpenoids, and phenolics which act as allelochemicals through highly diverse modes of action leading to major changes on the arthropods’ physiology and behavior. Thus, they represent a complementary and alternative strategy to manage populations of pests and vectors. In this framework, the present Special Issue welcomes original research articles and reviews shedding light on recent advancements about the use of plant secondary metabolites and related formulations against arthropod targets of health and agricultural importance. This Special Issue welcomes contributions on the following topics: - Phytochemical analysis and biological evaluation of plant-borne secondary metabolites; - Lethal and sub-lethal effects of plant-borne insecticides and acaricides; - Repellent effects of plant-borne secondary metabolites on insects and mites; - Modes of action of green insecticides, acaricides, and repellents; - Toxicity of green insecticides and acaricides on non-target species, including aquatic organisms; - Structure–activity relationships characterizing green insecticides and acaricides; - Synergistic and antagonistic studies focusing on green insecticides and acaricides; - Development of insecticidal and acaricidal formulations with extended shelf-life and prolonged bioactivity in the field. Prof. Dr. Filippo Maggi Dr. Giovanni Benelli Guest Editor

Emerging Insect-Borne Diseases of Agricultural, Medical and Veterinary Importance

Current migrations, due to several causes, but mainly consequence of climate changes, are causing several problems in Southern Europe. Some migrations are evident and attract attention immediately; others are silent, but still important, like several ones involving agriculture and livestock. In the future, a number of products employed in pest control may lose their efficacy. Pesticide resistance should be considered an increasing problem, and more environmental-friendly control approaches against arthropod pests are urgently needed. Two examples from the South of Italy clearly explain the kind of arising alerts and the complex network involving abiotic and biotic causes. The first case is the growing number of blue-tongue disease outbreaks, vectored by Culicoides sp. The second case is the alarm concerning the olive trees epidemic disease in Apulia, due to the bacterium Xylella fastidiosa. The development of new pest control methods is required in order to minimize negative effects of currently marketed synthetic pesticides. In this scenario, natural product research can afford solutions as part of an integrated pest control system. Preliminary results concerning the use of neem, Azadirachta indica, in control of insect vectors are discussed

How aggressive interactions with biomimetic agents optimize reproductive performances in mass-reared males of the Mediterranean fruit fly

Mass-rearing procedures of insect species, often used in biological control and Sterile Insect Technique, can reduce the insects competitiveness in foraging, dispersal, and mating. The evocation of certain behaviours responsible to induce specific neuroendocrine products may restore or improve the competitiveness of mass-reared individuals. Herein, we used a mass-reared strain of Ceratitis capitata as model organism. C. capitata is a polyphagous pest exhibiting territorial displays that are closely related to its reproductive performance. We tested if the behaviour of C. capitata males could be altered by hybrid aggressive interactions with a conspecific-mimicking robotic fly, leading to more competitive individuals in subsequent mating events. Aggressive interactions with the robotic fly had a notable effect on subsequent courtship and mating sequences of males that performed longer courtship displays compared to naïve individuals. Furthermore, previous interactions with the robotic fly produced a higher mating success of males. Reproductive performances of C. capitata males may be improved by specific octopaminergic neurones activated during previous aggressive interactions with the robotic fly. This study adds fundamental knowledge on the potential role of specific neuro-behavioural processes in the ecology of tephritid species and paves the way to innovative biotechnological control methods based on robotics and bionics

Eco-friendly contro strategies against the asian tiger mosquito, Aedes albopictus (Diptera: Culicidae): repellency and toxic activity of plant essential oils and extracts.

The economic and health problems related to the Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae), are due to its ectoparasitic behaviour and to the transmission of many diseases, particularly arbovirus and parasites. The difficulty to control the larval instars of A. albopictus, the reduced effectiveness and high environmental impact of adulticide treatments, highlight that the most effective solution to protect against A. albopictus is the use of repellent products for personal use such as DEET (N, N-diethyl-3-methylbenzamide). This compound showed a high repellent power in time but also some disadvantages including toxic effects on humans, especially on children and elderly. On this purpose, natural substances acting as repellent, such as plant essential oils and extracts, are considered very promising. Here we reported a critical review of our researches on repellence exerted by six different essential oils. The most effective essential oil was C. sativum. Furthermore, we discussed our research work conducted on ten essential oils tested as alternative larvicidal compounds. Following the dedicated WHO method, we proved that R. chalepensis EO was the most effective larvicidal among ten tested essential oils. Moreover, as regards to plant extracts, here we conducted bioassays to evaluate if the methanolic neem cake extract and its fractions of increasing polarity exhibit good mortality rates against A. albopictus larvae. We believe that the chance to use natural products such as essential oils and neem cake extracts, effective at lower doses when compared to synthetic products currently marketed, could be an advantageous alternative to build newer and safer mosquito control tools

Editors' Introduction

The chronicles of the Covid 19 days and forced lockdown, have often shown us the many difficulties that schools, hospitals, nursing homes, and prisons encountered when they found themselves managing the pandemic emergency with the normality of existence, but the difficulties particularly came to the surface when the ordinary situation was already compromised by atavistic problems. This was particularly true for prison institutions, which news stories at the time of the first wave of covid denounced as being on the verge of collapse, with inmates in revolt. This was because of the complexity of managing vigilance and control along with the increasingly pressing requests on behalf of inmates, for more information and contacts with the outside world; requests which the pandemic not only slowed down in fulfilling but made even more extreme and insisten