Spatial distribution of Lolium rigidum seedlings following seed dispersal by combine harvesters

This paper considers the relationships between the dispersal of seeds and the distribution pattern of an annual weed. A comparative study of seed dispersal by combine harvesters, with and without a straw chopper attached, was established using Lolium rigidum, a common weed in Mediterranean cereal crops. Seed dispersal distance was quantified and the relationships between dispersal and fine‐scale seedling distribution evaluated. Primary dispersal of L. rigidum seeds occurs in a very limited space around the parent plants, but the density of seed is low because most seeds do not fall from spikes spontaneously. In contrast, many seeds are spread by combine harvesters. In this study the maximum dispersal exceeded 18 m from established stands in cereal fields, although the modal distance was close to the origin. In addition, the action of the combine harvesters tended to accumulate L. rigidum seeds predominantly under the straw swath, with some lateral movement. This action could explain the fine‐scale banded pattern of L. rigidum in cereal fields. Although the treatment of straw by the standard and straw chopper combines differed, the resultant seed distribution showed few differences.     

Review of the current situation for Solanum elaeagnifolium in the Mediterranean Basin

Silverleaf nightshade (Solanum elaeagnifolium, Cav.) is one of the important invasive plant species in Mediterranean Basin countries. Over the last 60 years, this plant has gone from a few accidental introductions to near monospecific populations in many areas of the Mediterranean Basin (in particular Greece and Morocco). Recent findings from Lebanon show that the invasion is ongoing. Solanum elaeagnifolium has a negative impact on crops, causing up to 75% yield loss, as well as an indirect impact by harbouring plant pests and diseases. Solanum elaeagnifolium is toxic to livestock and has a negative affect on the quality of life for humans. Losses of potential resource or revenue caused by its invasion include: decreased forage quality on grazing lands; decreased cropping land and amenity values of public space; increased water loss; increased water conveyancing costs; and increased forest restoration costs. Available control techniques need to be strengthened to reduce the impact of S. elaeagnifolium and prevent its spread. More attention needs to be devoted to biological control, which could provide regional management of this invasive alien plant. Sustainable management of S. elaeagnifolium will require coordination, education and support across the affected countries. Governments must have the means to detect, manage and control S. elaeagnifolium.     

Epitrix flea beetles: new threats to potato production in Europe

Epitrix tuberis and E. cucumeris are major pests of potatoes in North America. E. tuberis causes the most serious damage because the larval feeding can cause superficial serpentine tunnelling on the surface of tubers as well as deeper pits. This damage can make crops unmarketable. By contrast, E. cucumeris mainly damages the foliage, and yield losses can occur when the adults reach high densities. In 2004, potato tuber damage characteristic of E. tuberis was seen in Portugal. In 2008, damage was more widespread and severe. E. cucumeris and a lesser known species, E. similaris, were recorded in affected fields. E. similaris has since been found across Galicia, Spain. E. similaris is thought to be the most likely cause of the tuber damage in Portugal, but it is possible that E. cucumeris or an as yet undetected Epitrix species is causing the damage. In 2010, a pest risk assessment for the Euro‐Mediterranean area identified the movement of adults and pupae with seed or ware potatoes and associated soil as being the highest‐risk pathways for the spread of Epitrix. In 2012, EU emergency measures were agreed to reduce the risk of further introductions and the rate of spread of these pests.     

Automated detection of the yellow-legged hornet (Vespa velutina) using an optical sensor with machine learning

BACKGROUND

The yellow-legged hornet (Vespa velutina) is native to Southeast Asia and is an invasive alien species of concern in many countries. More effective management of populations of V. velutina could be achieved through more widespread and intensive monitoring in the field, however current methods are labor intensive and costly. To address this issue, we have assessed the performance of an optical sensor combined with a machine learning model to classify V. velutina and native wasps/hornets and bees. Our aim is to use the results of the present work as a step towards the development of a monitoring solution for V. velutina in the field.

RESULTS

We recorded a total 935 flights from three bee species: Apis mellifera, Bombus terrestris and Osmia bicornis; and four wasp/hornet species: Polistes dominula, Vespula germanica, Vespa crabro and V. velutina. The machine learning model achieved an average accuracy for species classification of 80.1 ± 13.9% and 74.5 ± 7.0% for V. velutina. V. crabro had the highest level of misclassification, confused mainly with V. velutina and P. dominula. These results were obtained using a 14-value peak and valley feature derived from the wingbeat power spectral density.

CONCLUSION

This study demonstrates that the wingbeat recordings from a flying insect sensor can be used with machine learning methods to differentiate V. velutina from six other Hymenoptera species in the laboratory and this knowledge could be used to help develop a tool for use in integrated invasive alien species management programs. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Emergence of tomato leaf curl New Delhi virus in Italy: estimation of incidence and genetic diversity

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) identified for the first time in 1995 in Asia, from where it spread into several countries of the Mediterranean basin. ToLCNDV was found in Spain in 2012, and subsequently in Tunisia and Italy. The first outbreak in Italy occurred at the end of 2015 in Trapani province (Sicily) on zucchini squashes. Then in 2016, ToLCNDV was found in infected zucchini plants in Campania, Lazio and Sardinia regions, and in 2017 in Calabria. This study addressed the dispersion and genetic diversity of ToLCNDV isolates in Italy. A total of 1400 plants were analysed. Phylogenetic analysis showed low variability among the Italian isolates, probably as a consequence of the recent introduction and rapid spread of this virus in Italy. Two statistically significant clusters were reported: one grouping only Italian isolates and the other grouping Italian, Spanish, Tunisian and Moroccan isolates. Furthermore, the highest incidence of ToLCNDV was observed in Sicily, although the disease also appears to be critical in other Italian regions. In this work, a high efficiency of ToLCNDV mechanical transmission into Cucurbita pepo, Cucumis melo inodorus and Cucumis melo cantalupensis has been demonstrated. The rapid spread of ToLCNDV in the Mediterranean basin represents a threat for horticultural production, thus it is very important to develop suitable crop management practices, applying genetic resistance strategies and more restrictive phytosanitary measures.     

Species spectra,distribution and host range of cucurbit powdery mildews in the Czech Republic,and in some other European and Middle Eastern countries

The occurrence and geographic distribution of powdery mildew on cucurbits was studied in the Czech Republic, Austria, France, Germany, Great Britain, Italy, Slovakia, Slovenia, Spain, Switzerland, the Netherlands, as well as in Turkey and Israel, during the period 1995–2000. In total, 599 leaf samples with powdery mildew symptoms were collected from cucurbits from 166 locations within the Czech Republic; an additional 69 samples were collected from 42 locations elsewhere. Two powdery mildews (Golovinomyces cichoracearum and Podosphaera xanthii) were identified. The host range included the cultivated cucurbits (Cucumis melo, C. sativus, Cucurbita pepo, C. maxima, and Citrullus lanatus) and several other species. P. xanthii was the only powdery mildew pathogen found in Spain, Israel, and Turkey. P. xanthii and G. cichoracearum were detected in the other surveyed countries, occurring in both mixed infections and separately. In the more northerly latitudes and higher elevations, G. cichoracearum is more often the single species. G. cichoracearum was the dominant powdery mildew species in the Czech Republic (detected in 98.8% of the locations there); P. xanthii was found as the lone species in 1.2% of locations. At 28.4% of locations, G. cichoracearum was found with P. xanthii as mixed infections. The hyperparasitic fungus Ampelomyces quisqualis was found in 30% of the samples from the Czech Republic and was also recorded in Austria, Italy, Slovenia, Switzerland, and Great Britain.     

Invasiveness of agronomic weed species in wheat in Western Australia

Weed seeds are introduced to agronomic systems naturally or through human-mediated seed dispersal, and introduced seeds have a high chance of being resistant to selective, in-crop herbicides. However, colonisation (invasion) rates for a weed species are usually much lower than rates of seed dispersal. The current research investigated colonisation of a winter annual wheat cropping system in Western Australia by a range of winter or summer annual weed species. The weed seeds were sown (at 100 seeds/m²) directly before seeding the crop in 2016 and allowed to grow in the following 3 years of wheat. Selective herbicides were not applied, to simulate growth of weed populations if the initial seed had been resistant to herbicide. Bromus diandrus, Hordeum leporinum, Rumex hypogaeus, Sonchus oleraceus, Polygonum aviculare, Lolium rigidum, Citrullus amarus and Tribulus terrestris colonised the crop, while Dactyloctenium radulans, Chloris truncata and Salsola australis failed to establish over 3 years. The most successful weed was B. diandrus, with a plant density of 1,170/m² by the third year and seed production of 67,740/m². The high density of B. diandrus reduced wheat density by 76% in the third year and reduced average yield by 36%. Lolium rigidum reduced average yield by 11%, and the other weed species did not affect crop yield. Further research is required on the invasiveness of these species in other regions, but it is clear that the spread of B. diandrus to new areas or the introduction of resistant B. diandrus seeds via contaminated grain should be avoided.     

Patterns of disease and host resistance in spatially structured systems

We use data from species of the anther-smut fungi and the host plants Lychnis alpina and Silene dioica to show that spatial structuring at different scales can influence patterns of disease and host resistance. Patterns of disease and host resistance were surveyed in an archipelago subject to land-uplift where populations of S. dioica constitute an age-structured metapopulation, and in three contrasting areas within the mainland range of L. alpina, where population distributions range from continuous, through patchy but spatially connected to highly isolated demes. In S. dioica, disease levels depend on the age, size and density of local patches and populations. Disease is most predictably found in larger dense host patches and populations of intermediate age, and more frequently goes extinct in small old populations. The rate of local disease spread is affected by the level of host resistance; S. dioica populations showing an increase in disease over time are more susceptible than populations where the disease has remained at low levels. Among-population variation in resistance is driven by founding events and populations remain differentiated due to limited gene flow between islands. As observed in the L. alpina system, when populations are more connected, a greater fraction of populations have disease present. Results from a simulation model argue that, while increased dispersal in connected systems can increase disease spread, it may also favour selection of host resistance which ultimately reduces disease levels within populations. This could explain the observed lower disease prevalence in L. alpina in regions where populations are more continuous.     

Plane decline in European and Mediterranean countries: associated pests and their interactions

Surveys on the spread of the main pests of plane ( Platanus spp.) and on their influence on the decline of this genus in recent years have been carried out in various European countries. Of the primary pests which have been detected, Ceratocystis fimbriata f.sp. platani , agent of canker stain, has spread through several of the northern Mediterranean countries, causing death of trees; Gnomonia platani , agent of anthracnose, has spread mainly in the north-central Mediterranean areas; Microsphaera platani , agent of powdery mildew, has spread throughout almost all Mediterranean countries; so also has the insect Corythucha ciliata , which causes yellowing of the foliage. On trees declining under the interaction of these pests, secondary pests, agents of bark necrosis and, above all, of wood decay, are often detected. Ganoderma spp. are the main wood-decaying pathogen and can cause lethal root rots, especially if favoured by various kinds of stress. The trends and interaction of these pests in northern Italy are considered and control measures are discussed.     

Eradication and control of invasive alien plants in the Mediterranean Basin: towards better coordination to enhance existing initiatives

The European and Mediterranean Plant Protection Organization (EPPO), in the framework of its activities in the Mediterranean Basin, launched a questionnaire to gather information on eradication actions and control actions for invasive alien plants. Thirty‐four (34) eradication actions were reported, 16 occurring in Spain, 7 in Italy, 7 in France, 1 in Portugal, 1 in Malta, and 2 on the southern rim of the Mediterranean, with 1 in Israel and 1 in Tunisia. Twenty‐two (22) species were targeted, and the habitats where such actions were undertaken most frequently were coastal dunes, sandy shores and aquatic ecosystems. Most of the species that have been the object of an eradication action were known invasive species recorded in the EPPO lists, such as Ailanthus altissima, Buddleia davidii, Carpobrotus spp., Eichhornia crassipes, Ludwigia peploides, Pennisetum setaceum, Pistia stratiotes, Solanum elaeagnifolium and Sicyos angulatus. Other eradicated species have a limited distribution in the EPPO region and may represent emerging invasive plants, such as Ambrosia confertifolia, Cylindropuntia rosea, Leersia oryzoides, Leptochloa fusca subsp. uninervia and Marsilea drummondii. Control actions concerning 90 species were also reported. A large number of eradication actions, as well as management actions, are therefore happening in Mediterranean countries. At present countries appear to operate with complete autonomy, without consulting neighbouring countries or other stakeholders within the country. There is therefore a need for coordination of new eradication actions.     

Spread of the yellow‐legged hornet Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae) across Northern Spain

The yellow‐legged hornet Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae) is an Asian native species which has now established in parts of Europe. Since its detection in France in 2005 it has spread quickly across the country and also spread to the Iberian Peninsula. This paper compiles the most recent data about its spread and distribution on the Spanish mainland. The efficacy of using Véto‐Pharma© traps as a control method is also discussed.     

Vegetative Compatibility Grouping of Fusarium oxysporum f. sp. gladioli from Saffron

Fusarium corm rot of saffron (Crocus sativus L.), incited by Fusarium oxysporum f. sp. gladioli, causes severe yield losses in Italy. Major symptoms during flowering (October–November) include yellowing and wilting of shoots, basal stem rot and corm rot. Sixty-four isolates of F. oxysporum f. sp. gladioli, obtained from infected saffron crops located in Italy (Abruzzi, Tuscany and Umbria) and in Spain, were characterized by pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing (nit) mutants were used to determine vegetative compatibility among the isolates of the pathogen with the aim of examining the genetic relatedness among populations from different locations. All the isolates belonged to vegetative compatibility group 0340. Since saffron shares susceptibility to F. oxysporum f. sp. gladioli with other ornamental plants of the Iridaceae (Crocus, Gladiolus, Iris and Ixia), it is likely that a clone of the pathogen (VCG 0340) was introduced with other hosts and is responsible for the disease outbreak observed on saffron in Italy. Alternatively, or additionally, the clone of F. oxysporum f. sp. gladioli causing disease on saffron in other countries may have spread to the saffron fields in Italy through the import and dispersal of infested propagation material.     

Frosty pod of cacao: a disease with a limited geographic range but unlimited potential for damage

ABSTRACT Moniliophthora roreri, the cause of frosty pod rot (FP), is a specialized fungal pathogen (family Marasmiaceae) that invades only actively growing pods of cacao, Theobroma cacao, and related species of Theobroma and Herrania. FP damages pods and the commercially important seeds that some of these species produce. M. roreri was confined to northwestern South America until the 1950s. Its appearance in Panama in 1956 signaled a change in its geographic distribution. Now, it is found in 11 countries in tropical America. The fungus is currently in an active dispersal phase, possibly due to an increase in human-mediated spread. FP is more destructive than black pod (Phytophthora spp.) and more dangerous and difficult to control than witches' broom, caused by Moniliophthora (Crinipellis) perniciosa. The aggressiveness of M. roreri, its capacity to survive different environmental conditions, its rapid natural dispersal, its propensity for man-mediated dispersal, and the susceptibility of most commercial cacao genotypes, all indicate that FP presents a substantial threat to cacao cultivation worldwide.     

四川省小麦条锈病流行区划及菌源传播路径分析

四川省是我国小麦条锈病菌Puccinia striiformis Westend f.sp.tritici Eriks的菌源地和常发区,近10年秋苗病害始见期提前、流行期加长、危害损失呈上升趋势.在实地调查基础上,利用GIS技术对全省132个小麦主产县(市、区)1987-2006年小麦条锈病发生情况进行系统分析.结果表明,四川省小麦条锈病流行区域可划分为川西北越夏区、川西南越夏及冬繁区、盆地冬繁区和川东南春季流行区.GIS软件分析发现病菌孢子在四川盆地内的传播路径为沿岷江、涪江、沱江和嘉陵江等4条河流自北向南、自西向东传播.     

TaqMan real-time PCR method for detection of <Emphasis Type="Italic">Discula destructiva</Emphasis> that causes dogwood anthracnose in Europe and North America

Dogwood anthracnose, caused by the asexual filamentous fungus Discula destructiva Redlin, is a disease of several Cornus L. species. First reported in the 1970s in the United States, the pathogen has devastated North American dogwood populations causing widespread loss that has greatly impacted forest ecosystems. In the early 2000s, the disease was discovered in Italy and Germany, spread probably through the ornamental nursery trade. The origin of D. destructiva in North America remains a mystery. To facilitate studies on its origin and dispersal, a fast and accurate method using real-time PCR was developed in this study to detect and quantify D. destructiva. The assay was validated with samples from the U.S., Italy, and Switzerland as well as phylogenetically closely related fungal species, and other fungi and oomycetes commonly found on Cornus. This method allows for fast and sensitive detection of D. destructiva in host tissue and should be useful in disease management and pest interception to prevent further spread of the pathogen.     

Goat horns: Platforms for viroid transmission to fruit trees?

Mechanical inoculations with contaminating tools and propagation of infected budwood were considered the main causes for the omnipresence of multiple viroid species among citrus and other Middle Eastern and Mediterranean fruit trees and grapevines. However, neither means could explain viroid infections of wild trees — scattered on terrains inaccessible to humans — nor the finding of similar viroids among graft-incompatible plants. Northern hybridization of RNA extracts made of scrapings from the surfaces of goat (Capra hircus) horns that were rubbed against etrog (Citrus medica) stems infected with a citrus viroids complex, revealed accumulation of considerable amounts ofCitrus exocortis viroids (CEVd) andHop stunt viroids (HSVd). Experimental transmission of both CEVd and HSVd was obtained by rubbing healthy citrus plants with goat horns that had been rubbed 24 h earlier on infected etrog stems. These results implicate goats as possible vectors of viroids. Transmissionvia goats could have facilitated the long-range spread of viroids among cultivated and wild plants andvice versa and also among graft-incompatible plants.     

The current status of Tuta absoluta in Italy

The cultivation of tomato, and other Solanaceae, is of major importance for European agriculture. The revival of the Mediterranean diet is helping to bring back to the tables of European peoples many Solanaceae, and particularly tomato. The European and International demand for processed tomato products has sharply increased the interest given to this culture. Nevertheless tomato is a plant strongly infested by insect pests. This paper presents the state of the art concerning the spread of the invasive Gelechiidae moth, Tuta absoluta (Meyrick) in Italy, along with data on surveying strategies to monitor the insect at regional level.     

First data on the flight activity and distribution of the ambrosia beetle Xylosandrus compactus (Eichhoff) on carob trees in Sicily

The factors influencing the entry and the spread of the black twig borer, Xylosandrus compactus (Eichhoff), in the Mediterranean environment have not yet been characterized. Following its first report in Sicily (southern Italy) in 2016, and due to the high level of damage it causes on one of its host plants (Ceratonia siliqua L.), the flight activity of the pest was studied there. Monitoring was performed from spring 2017 to summer 2018 by exposing red cross‐shaped sticky traps combined with ethanol‐baited bottle traps. The three monitored sites were selected at different altitudes, representing the southern Mediterranean environment where the carob tree is widely present. The results showed that the pest populations are influenced by climatic factors. In particular, the first adults were caught when the maximum daily temperatures were stably higher than 20°C over several continuous days. Xylosandrus compactus occurred widely in the monitored territory and was continuously caught from spring to autumn. Furthermore, the traps used proved to be effective for intercepting the spring flight of the overwintering females. Moreover, the ability of the beetle to spread from a new infested area was also studied. It seems that the pest can spread more than 8 km from the last infested site of the previous flying season. It was not present above altitudes of 400 m in the conditions of the present study. This study represents the first step to better understand the behaviour of X. compactus in a newly colonized environment.     

Pest risk analysis of rice root-knot nematode (Meloidogyne graminicola) for the Italian territory

Meloidogyne graminicola is one of the most harmful organisms associated with rice cultivation throughout the world. Until recently, M. graminicola was present only in Asia, parts of the Americas, Madagascar and South Africa. In 2016, it was detected for the first time in mainland Europe (Northern Italy) and subsequently added to the EPPO Alert List. In this study, the risk posed by this nematode to rice in Italy was assessed using an internationally developed pest risk analysis scheme. In the risk assessment section, information about biology, pathways for entry, the likelihood of establishment, spread and negative impact of M. graminicola are reviewed. Internationally, its spread is more likely through the movement of infested host plants, soil or growing medium and non-host plant parts that may have growing medium attached, from areas where this nematode occurs. Migrant waterbirds, machinery and travellers were also considered as possible pathways for entry. The probability of establishment is very likely due to the suitable environmental conditions and the large range of host plant species present in Italy. This and the nematodes’ ability to survive for long periods in low oxygen environments make the control of M. graminicola very difficult.     

SSR assessment of Phytophthora infestans populations on tomato and potato in British gardens demonstrates high diversity but no evidence for host specialization

Phytophthora infestans populations can differ in composition as a result of host specialization on tomato and potato hosts. In Great Britain many amateur gardeners grow outdoor tomatoes but there is little or no commercial tomato production outdoors. This study analysed isolates of P. infestans from British gardens with 12 multiplexed simple sequence repeat markers that are used to monitor the disease on commercial potato crops. Samples of P. infestans from tomato hosts were collected in 3 years and from potato in 1 year from across Great Britain. Seven previously unreported clonal lineages were detected in garden populations and higher frequencies of unique clonal lineages (28–40%) were present compared with populations from British commercial potato crops reported elsewhere. Garden populations had a lower proportion (11–48% less) of the most common lineages (13_A2 and 6_A1) that together made up at least 86% of the commercial potato populations during the sampling period. Host species accounted for only 2·0% of molecular variance detected between garden potato‐ and tomato‐hosted samples. No significant difference in clonal lineage composition was found between host species in Great Britain and this could be due to the whole P. infestans population overwintering on potato. British garden populations on both hosts were much more diverse than those on commercial potato crops; this finding may be influenced by less frequent fungicide use by gardeners and a higher diversity of unsprayed susceptible potato cultivars, enabling metalaxyl‐sensitive and less aggressive genotypes to survive in gardens.