Can Pest Management and Cultivar Affect Phytoptus avellanae Infestations on Hazelnut?

The big bud mite Phytoptus avellanae is a resurgent pest of hazelnut, Corylus avellana, causing substantial yields reductions in many productive areas. Mites colonise and develop within healthy buds which become swollen, with subsequent alteration to the plant's development. To date, there has been limited knowledge on how the cultivar and pest management strategies affect infestations. This study explored these aspects through two ad hoc experiments carried out in central Italy. In the first experiment, the susceptibility of 11 cultivars with different geographic origins was tested in a germplasm hazelnut collection. The second experiment assessed the infestation level in orchards with integrated pest management (IPM) and organic pest management strategies and in a renaturalised environment (a former agricultural area now converted in a natural park). The results showed that the most and the least susceptible cultivars were Tonda Gentile and Nocchione, respectively. No significant differences were found between IPM and organic management, but they were both different to the renaturalised environment. The outcomes of this research can serve as a valuable reference and can be applied to all current or potential hazelnut cultivation areas characterised by the same environmental conditions.

Genomic and Pathogenic Characterization of Akanthomyces muscarius Isolated from Living Mite Infesting Hazelnut Big Buds.

The capability of entomopathogenic fungi to live as plant endophytes is well established. However, their presence in undiscovered environmental niches represents the beginning of a new challenging research journey. Recently, Akanthomyces muscarius (Ascomycota, Cordycipitaceae) (Petch) Spatafora, Kepler & B. Shrestha was isolated from hazelnut buds infested by the big bud mite pest Phytoptus avellanae Nalepa, which makes the buds swollen, reddish, and unable to further develop. Gall formation is known to be regulated by a consortium of microbes and mites, and to better understand the possible role of A. muscarius within the infested gall, its whole genome sequence was obtained using a hybrid approach of Illumina and Nanopore reads. The functional and comparative genomics analysis provided within this study may help answer questions related to the ecology and the entomopathogenicity of this fungus.

A bud's life: Metabarcoding analysis to characterise hazelnut big buds microbiome biodiversity.

Despite Corylus avellana L. being an economically important shrub species known for its resilience to adverse environmental conditions, it constantly faces attacks from a plethora of biotic entities. Among these, the mite pest Phytoptus avellanae is gaining importance, causing economic losses every year. This mite colonises the new generative and vegetative buds, leading them to become swollen and reddish, and drastically reducing hazelnut production. The biology behind gall formation is still poorly understood. This study provides a qualitative and quantitative description of the microbiome in both healthy and infested buds of two economically important hazelnut cultivars through metabarcoding of fungal ITS and bacterial 16 S. Potentially pathogenic genera such as Fusarium and Pseudomonas were predominant in the infested buds, along with the obligate intracellular bacterial genus Wolbachia. Akanthomyces muscarius was instead isolated from culture-based methods only from the infested buds. These findings could improve the understanding of gall ecology, supporting the management of mite populations, and they could also serve as a milestone for further studies on low-impact, monitoring-driven, and genetically targeted control strategies.

Life tables in entomology: A discussion on tables' parameters and the importance of raw data.

Life tables are one of the most common tools to describe the biology of insect species and their response to environmental conditions. Although the benefits of life tables are beyond question, we raise some doubts about the completeness of the information reported in life tables. To substantiate these doubts, we consider a case study (Corcyra cephalonica) for which the raw dataset is available. The data suggest that the Gaussian approximation of the development times which is implied by the average and standard error usually reported in life tables does not describe reliably the actual distribution of the data which can be misleading and hide interesting biological aspects. Furthermore, it can be risky when life table data are used to build models to predict the demographic changes of the population. The present study highlights this aspect by comparing the impulse response generated by the raw data and by its Gaussian approximation based on the mean and the standard error. The conclusions of this paper highlight: i) the importance of adding more information to life tables and, ii) the role of raw data to ensure the completeness of this kind of studies. Given the importance of raw data, we also point out the need for further developments of a standard in the community for sharing and analysing data of life tables experiments.

Are the ladybugs Cryptolaemus montrouzieri and Exochomus quadripustulatus (Coleoptera: Coccinellidae) candidate predators of Toumeyella parvicornis (Hemiptera: Coccidae)?

BACKGROUND: Toumeyella parvicornis is an alien pest of recent introduction in Italy that infests stone pines (Pinus pinea L.), its main host plant in Europe. Infestations are currently controlled through endotherapic treatments, but the high costs and the long-term inefficacy highlight the need for alternative control strategies applicable in natural systems as well. An analysis of the effectiveness of autochthonous and naturalized predators is the first step to achieve this goal. This work focused on two candidate predators, Exochomus quadripustulatus and Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), that may potentially control T. parvicornis. The analysis was carried out under laboratory-controlled and semi-field conditions. RESULTS: Laboratory tests were carried out to assess: (i) the predation rate of the ladybugs over different densities of pest preimaginal stages, and (ii) the effect of the presence of heterospecific and conspecific predators on the attractiveness of prey colonies. Semi-field experimentations were carried out by wrapping infested stone pine twigs with net sleeves and applying one of three treatments: (i) Exochomus quadripustulatus, (ii) Cryptolaemus montrouzieri, and (iii) control containing only the pest population. Both the ladybugs were attracted by T. parvicornis, offered as prey. Exochomus quadripustulatus was more attracted to conspecific and heterospecific ladybugs than Cryptolaemus montrouzieri and responded to prey more quickly. CONCLUSIONS: The results obtained could be useful for planning further experimentations to explore the potential use of these predators in biological control programs that may be applied in infested areas. Besides the use in an urban context, where pesticide use is strongly limited, the release of natural enemies may help safeguard stone pine forests. © 2024 Society of Chemical Industry.

Toumeyella parvicornis versus endotherapic abamectin: three techniques, 1 year after.

BACKGROUND: Toumeyella parvicornis is an invasive soft scale insect native to North America that is rapidly spreading in Italy and France, provoking severe infestations on Pinus pinea L. To date, the control of this pest is entrusted to three endotherapic techniques whose short-term efficacy is partially known. No information on long-term efficacy is currently available, although fundamental. This work aims to report on the long-term effect that abamectin-based insecticides, injected with the three different techniques, have on adult female populations. RESULTS: The study was carried out in an infested P. pinea forest in the area of Rome, Italy. Results showed that the tested methods had a similar long-term effect, and only in one case there were differences with the untreated control. Multiresidue analysis reported a zero level of abamectin in plant tissues 14 months apart from injection, except for one treatment where pesticide concentration was just above the limit of quantification. CONCLUSIONS: This study represents the first long-term evaluation about endotherapic control strategy against T. parvicornis. In fact, the pest may quickly bring the death and fall of the stone pines, representing a concerning risk for citizens, however, control actions to manage it are still partially known and deserve more in-depth investigations. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Using Species Distribution Models (SDMs) to Estimate the Suitability of European Mediterranean Non-Native Area for the Establishment of Toumeyella Parvicornis (Hemiptera: Coccidae).

The pine tortoise scale, Toumeyella parvicornis, is an insect native to the Nearctic region that is able to infest several Pinus species. It can cause weakening, defoliation and, at high infestation levels, tree death. After its first report in Italy in 2015, the pest spread rapidly over the surrounding areas and was reported in France in 2021. Due to the threat that this pest poses to pine trees, the suitability of European Mediterranean basin areas for T. parvicornis at different spatial scales was estimated by constructing species distribution models (SDMs) using bioclimatic variables. Our results showed that several coastal areas of the Mediterranean basin area could be suitable for T. parvicornis. Based on performance assessment, all the SDMs tested provided a good representation of the suitability of European Mediterranean non-native area for T. parvicornis at different spatial scales. In particular, most of the areas with a medium or high level of suitability corresponded to the geographical range of distribution of different Pinus spp. in Europe. Predicting the suitability of European Mediterranean areas for T. parvicornis provides a fundamental tool for early detection and management of the spread of this pest in Europe.

Effects of Biochar on the Growth and Development of Tomato Seedlings and on the Response of Tomato Plants to the Infection of Systemic Viral Agents.

Biochar is a rich carbon product obtained by pyrolysis of biomass under a limited supply of oxygen. It is composed mainly of aromatic molecules, but its agronomic value is hard to evaluate and difficult to predict due to its great variable characteristics depending on the type of starting biomass and the conditions of pyrolysis. Anyway, it could be used as soil amendment because it increases the soil fertility of acidic soils, increases the agricultural productivity, and seems to provide protection against some foliar and soilborne diseases. In this study, the effects of biochar, obtained from olive pruning, have been evaluated on tomato seedlings growth and on their response to systemic agents' infection alone or added with beneficial microorganisms (Bacillus spp. and Trichoderma spp.). First, experimental data showed that biochar seems to promote the development of the tomato seedlings, especially at concentrations ranging from 1 to 20% (w/w with peat) without showing any antimicrobial effects on the beneficial soil bacteria at the tomato rhizosphere level and even improving their growth. Thus, those concentrations were used in growing tomato plants experimentally infected with tomato spotted wilt virus (TSWV) and potato spindle tuber viroid (PSTVd). The biochar effect was estimated by evaluating three parameters, namely, symptom expression, number of infected plants, and pathogen quantification, using RT-qPCR technique and -ΔΔCt analysis. Biochar at 10-15% and when added with Trichoderma spp. showed that it reduces the replication of PSTVd and the expression of symptoms even if it was not able to block the start of infection. The results obtained on TSWV-infected plants suggested that biochar could contribute to reducing both infection rate and virus replication. For systemic viral agents, such as PSTVd and TSWV, there are no curative control methods, and therefore, the use of prevention means, as can be assumed the use biochar, for example, in the nursery specialized in horticultural crops, can be of great help. These results can be an encouraging starting point to introduce complex biochar formulates among the sustainable managing strategies of plant systemic diseases.

Endotherapic treatment to control Toumeyella parvicornis Cockerell infestations on Pinus pinea L.

BACKGROUND: The pine tortoise scale, Toumeyella parvicornis (Cockerell, 1897), is a damaging insect pest native to North America. Its accidental introduction into Europe, where it was first reported in central-southern Italy, is leading to severe infestations among stone pine trees, Pinus pinea L. causing severe infestations and generating a major risk to the health and safety of the citizens as well. This preliminary study aimed at finding an effective low-impact control strategy against Toumeyella parvicornis. We evaluated the effect of endotherapic abamectin injected into infested stone pines in the Parco Archeologico di Ostia Antica (Rome). RESULTS: Results showed that endotherapic abamectin significantly reduced the pine tortoise adult female populations and had a persistence into plants of approximately 60 days. The first trace of abamectin on the plant's crown was detected 1 month after the treatment. Moreover, the survey highlighted a higher presence of the pest on the twigs of the plants than on needles. CONCLUSIONS: These findings offer an important tool in fighting the damaging activity of this phytophagous, especially in an urban context where interventions with treatments are strictly regulated by national laws. Endotherapy, in fact, would reduce the dispersion of active ingredients by drift, an aspect that could represent a valid alternative to manage plants in public areas. Given the actual lack of scientific information about other control solutions, abamectin endotherapic treatments would be the more effective strategy currently applicable. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The fungal community associated with the ambrosia beetle Xylosandrus compactus invading the mediterranean maquis in central Italy reveals high biodiversity and suggests environmental acquisitions.

In summer 2016 a severe infestation of the alien ambrosia beetle Xylosandrus compactus was recorded from the Mediterranean maquis in the Circeo National Park in Central Italy. Trees and shrubs were infested and displayed wilting and necrosis of terminal branches caused by the combined impact of the insect and associated pathogenic fungi. A preliminary screening carried out on captured adults resulted in the isolation of a discrete number of fungal taxa with different life strategies, ranging from true mutualist (e.g. Ambrosiella xylebori) to plant pathogens (Fusarium spp.). In the present study, high-throughput sequencing was applied to determine the total diversity and functionality of the fungal community associated with X. compactus adults collected in the galleries of three Mediterranean woody hosts, Quercus ilex, Laurus nobilis, and Ceratonia siliqua. The effect of season and host in determining the composition of the associated fungal community was investigated. A total of 206 OTUs composed the fungal community associated with X. compactus. Eighteen OTUs were shared among the three hosts, including A. xylebori and members of the Fusarium solani complex. All but two were previously associated with beetles. Sixty-nine out of 206 OTUs were resolved to species level, identifying 60 different fungal species, 22 of which already reported in the literature as associated with beetles or other insects. Functional guild assigned most of the fungal species to saprotrophs and plant pathogens. Effects of seasonality and host on fungal community assemblage were highlighted suggesting the acquisition by the insect of new fungal taxa during the invasion process. The consequences of enriched fungal community on the risk of the insurgence of novel threatful insect-fungus association are discussed considering direct and indirect effects on the invaded habitat.

Modelling Drosophila suzukii Adult Male Populations: A Physiologically Based Approach with Validation.

The Spotted Wing Drosophila (SWD), Drosophila suzukii (Matsumura), is a harmful insect pest for soft fruit cultivations. Even though its main hosts belong to the genera Prunus and Rubus, its high polyphagy and adaptability to new environments makes it a serious problem for farmers worldwide, who have reported several economic losses because of this pest. A wide series of proposals to control SWD are available and operate in line with the mechanisms of integrated pest management, demonstrating their high efficiency when applied at the opportune moment. This work aims to apply and validate a physiologically based model which summarises all the available information about D. suzukii biology, such as the relationship between environmental temperature and its development, fertility and mortality rates. The model provided, as a result, a description of a population of SWD females taking into consideration the multiple generations that occurred during the year. Simulations were then compared with field data collected in a three-year survey in two experimental fields located in the Sabina Romana area (Lazio, Italy). More specifically, D. suzukii males were monitored with traps in fields cultivated with mixed varieties of cherries and they were selected because of their clearer identification in comparison to females. Results showed a high level of reliability of simulations in representing the field data, highlighting at the same time that there is no discrepancy in simulating D. suzukii females in order to represent male populations.

Anteon hubeni a new species from Ecuador (Hymenoptera: Dryinidae).

BACKGROUND: Anteon is a speciose genus widespread in all zoogeographical regions, except Antarctica. NEW INFORMATION: A new species, Anteon hubeni sp. n., is described below from Ecuador, Pichincha Province. The new species is similar to Anteon oliveirai Olmi, known from Brazil, Minas Gerais. The main difference between these two species concerns the sculpture of the frons: in A. oliveirai, the frons shows two lateral keels around the orbits directed towards the antennal toruli, whereas in A. hubeni, these keels are not present. The key to the Neotropical species of Anteon is modified to include the new species.

Discovery of a new species of Embolemus Westwood (Hymenoptera: Embolemidae) from New Caledonia.

Embolemus villemantae sp. nov. (Hymenoptera: Embolemidae) is described from New Caledonia. The key to the males of the Australasian species of Embolemus is modified to include the new species.

Discovery of the transantarctic distribution of the genus Metanteon Olmi (Hymenoptera: Dryinidae), with description of a new species from New Caledonia.

Metanteon poirieri sp. nov. (Hymenoptera: Dryinidae: Anteoninae) is described from New Caledonia. The genus Metanteon Olmi, 1984, was known only from the southern region of Argentina and Chile. The unique species attributed previously to this genus is M. aerias (Walker, 1839), collected in Chile by Charles Darwin during his famous trip on the HMS Beagle. M. aerias is associated only with leafhoppers feeding on Southern Beeches (Nothofagus spp.), a genus of Nothofagaceae including species of trees and shrubs native to the southern Hemisphere in southern South America (Argentina, Chile) and Australasia (east and southeast Australia, New Zealand, New Guinea and New Caledonia). Like Nothofagus, Metanteon is a transantarctic organism.

Fungal community associated with adults of the chestnut gall wasp Dryocosmus kuriphilus after emergence from galls: Taxonomy and functional ecology.

The diversity of the fungal community associated with adults of Dryocosmus kuriphilus following emergence was examined using HTS analysis. Ascomycota dominated the fungal core-biome community. The functional guilds of the 90 taxa forming the core-biome were assessed, demonstrating three main groups: saprotrophs, plant pathogens and entomopathogens. Twenty-nine OTUs out of 90 were resolved to species level identifying 26 different fungal species. Among these species, many were cosmopolitan or previously recorded in Europe. Ten taxa were previously recorded on chestnut, including some recognized plant pathogens associated with foliage and green tissues such as Epicoccum nigrum, Gnomoniopsis castanea, Colletotrichum acutatum, Stromatoseptoria castaneicola, Ramularia endophylla. Beauveria bassiana; within the core microbiome, Fusarium larvarum represented the most abundant entomopathogenic species. Some of these species are known to impact directly or indirectly the vitality of the insects in the galls. The chestnut blight pathogen, Cryphonectria parasitica, was never found associated with D. kuriphilus. Based on the present study, an active role for D. kuriphilus as a vector of chestnut fungal endophyte/pathogens cannot be demonstrated but neither ruled out.

An updated checklist of the extant Western Palaearctic Dryininae (Hymenoptera, Dryinidae).

A checklist of 20 extant species of Dryininae (Hymenoptera, Dryinidae) from the Western Palaearctic subregion is presented.

A new species of the genus Dryinus Latreille (Hymenoptera, Dryinidae) from the USA.

A new species of Dryinus Latreille, 1804, is described from Georgia (USA). D. georgianus sp. nov. is morphologically similar to D. mexicanus (Perkins, 1907) and D. splendidus Guglielmino and Olmi, 2013, but is distinguished by the lateral ocelli not touching the occipital carina (in the other two species, the lateral ocelli touch the occipital carina). The key to the females of the Nearctic species of Dryinus group 1 is modified to include the new taxon.

Gonatopusjaliscanus sp. n., a new Pincer wasp from Jalisco, Mexico (Hymenoptera, Dryinidae).

A new species of Gonatopus Ljungh, 1810, G.jaliscanus sp. n., from Jalisco, Mexico, is described and illustrated. In the Neotropical region, G.jaliscanus is similar to G.forestalis Olmi, 1998, but it is distinguished by the black mesosoma (except prothorax, mesoscutum, and mesoscutellum that are yellow), and the metapostnotum being granulated and not rugose; in G.forestalis the mesosoma is completely black and the metapostnotum is granulated and strongly rugose. In the Nearctic region, the new species is morphologically similar to G.curriei Krombein, 1962, but it is distinguished by the dull and granulated metapostonotum; in G.curriei the metapostnotum is shiny and unsculptured. The new species belongs to Gonatopus group 7. The keys to the females of the Nearctic and Neotropical species of this group are modified to include the new taxon.

A new species of the genus Deinodryinus Perkins (Hymenoptera, Dryinidae) from the USA.

A new species of Deinodryinus Perkins, 1907, is described from the USA, Texas: D.bimaculatus sp. n. Morphologically the new species is similar to D.masneri (Olmi, 1984), but it is distinguished by the head lacking a frontal line and the forewing crossed by two dark transverse bands; in D.masneri the head shows a conspicuous frontal line and the forewing is hyaline and without dark transverse bands.

Does Gnomoniopsis castanea contribute to the natural biological control of chestnut gall wasp?

Gnomoniopsis castanea has been reported as the causal agent of necrosis of chestnut wasp (Dryocosmus kuriphilus) galls. The fungus is frequently observed on galls in chestnut stands infested by the insect in Italy. In the present study the impact of gall necrosis and the dynamic of its development have been studied in mature and young Castanea sativa stands in Central Italy during spring and early summer, before the D. kuriphilus adult flies. Results suggest that gall necrosis develops from resident endophytic inoculum of G. castanea. During the 2 y of monitoring, no differences were found in incidence and severity of the disease. Gall necrosis increased exponentially during the season, reaching 75,4% of galls totally necrotized in the investigated site in mid July. Gall necrosis was shown to have a severe impact on D. kuriphilus vitality, mostly impacting the adults inside the galls. Gall necrosis by G. castanea appears to efficiently control gall wasp in chestnut stands, although the high virulence of the fungus to chestnut fruits precludes its use as biocontrol agent in biological control strategies.