Anoplophora species in Europe: infestations and management processes1

By the end of summer 2005, four sites of infestation by Anoplophora glabripennis (Coleoptera, Cerambycidae) had been detected in three European countries: Austria in 2001, at Braunau am Inn; France in 2003, at Gien, and in 2004, at Sainte‐Anne‐sur‐Brivet; and Germany in 2004, at Neukirchen am Inn. Two sites of infestation by Anoplophora chinensis have been detected in two European countries: Italy in 2000, at Parabiago, and France in 2003, at Soyons. The history of the A. glabripennis and A. chinensis discoveries is presented, as well as the respective management responses (monitoring and destruction of the infested trees). By the end of summer 2005, the eradication was not yet fully achieved in any of the four A. glabripennis‐infested sites. In contrast, no new A. chinensis‐infested trees had been found at Soyons, France, since 2003. At Parabiago, Italy, monitoring is taking place: the A. chinensis infestation affects 16 municipalities over more than 60 km². By summer 2005, destruction on a large scale of the infested trees had not yet taken place, but tree‐cutting of more than 1000 trees had been planned for winter 2005‐06. Given the current substantial extent of the A. chinensis infestation near Milan, and the density of the established A. chinensis populations, there is a high probability that the status of the pest in Italy will soon be raised from ‘introduced’ to ‘invasive’.     

Inoculum potential and host range of Polymyxa betae and beet necrotic yellow vein furovirus1

The inoculum potential of Polymyxa betae and BNYVV was studied from 52 random samples of Belgian soils and 10 samples from other European countries, by culture of bait plants in tubes under controlled conditions on serial dilutions of the soils in sterile sand. P. betae was detected in all samples within the range of 0.01 to 27.1 infection units per g of soil. BNYVV was detected by ELISA on root extracts of bait plants grown on three Belgian soil samples. All the tested samples from rhizomania-infested areas in France, FRG, the Netherlands, Switzerland and Austria, were found to be infested by BNYVV by this technique. For BNYVV survey, the plant bait technique appears more reliable than the analysis of rootlets collected in the field and observation of external symptoms in case of low BNYVV infestations or non-expression because of unfavourable environmental conditions. P. betae isolates from various origins heavily infected Beta spp. but only moderately spinach. Chenopodium album was slightly infected by 2 of the 7 isolates, C. murale by 4 of them.     

The demarcation of Globodera rostochiensis and Globodera pallida infestations in fields for seed potatoes, using a Monte Carlo approach

A Monte Carlo approach was utilized to calculate the size of the demarcation unit, necessary to cover infestations with Globodera rostochiensis and Globodera pallida (PCN), detected with the new EU-sampling method. Results from 90 sampled fields were used to obtain frequency distributions of the central population density (CPD), the length and width gradients of infestation foci and the distance between 'primary' and 'secondary' foci within one field section in the direction of cultivation. With a simulation model written in R, a free software environment for statistical computing, the dimensions of the demarcation unit were calculated, based on the dimensions of the sampling unit, the position of the 'primary' infestation within the sampling unit and the size of the infestation focus. It is concluded that a demarcation of 90% of possible foci positions and dimension, analogous to the specified detection probability of the EU sampling method, provides sufficient security to demarcate any infestation. With the preferred sampling unit of 11 m width and 300 m length (1/3 ha sampled), used in The Netherlands, only 0.61% of the cyst numbers will be situated outside the demarcated unit. These cyst numbers compare to 0.17% of total amount of cysts in the EU infestation model: 1 focus with a CPD of 100 cysts kg⁻¹ and three foci with CPDs of 50 cysts kg⁻¹. The required demarcation area has a width of 36 m and a (maximum) length of 402 m and covers an unit of 1.5 ha. The methodology described can be applied to all proposed sampling methods and sampling unit dimensions.     

Survey on the distribution of the Horse Chestnut ScalePulvinaria regalisCanard (Hom., Coccidae) in Germany in the years 1996 to 1998

In the present study, the distribution of the Horse Chestnut Scale insectPulvinaria regalis Canard in Germany in the years 1996 to 1998 and tendencies in the variation of infestation levels during the past three years were investigated by a survey. A questionnaire was sent to the offices for green areas and environmental affairs of 121 cities in Germany with a population exceeding 75.000 citizens. Additional observations by the authors were also taken into consideration. A comparison to data from 1995 was conducted. In the year 1998, this arboricultural pest occurred in 34 cities (15 in 1995) and could be found in the areas of the Rhineland and the Ruhr-Valley, from Bonn in the south up to Münster (Westphalia) in the north and from Aachen in the west to Hagen and Dortmund in the east.P. regalis could also be detected in Offenbach and Frankfurt a. M., It also occurred southward along the rivers Rhine and Neckar in the cities of Mainz, Ludwigshafen, Freiburg and Stuttgart. The most southern point whereP. regalis was detected in July 1998 was Zürich in Switzerland. The first occurrence of the 19 new observed infestations withP. regalis took place in six instances before 1995, eight in 1995, three in 1996, and one each in 1997 and 1998. The investigations about tendencies in the variation of infestation levels revealed a decrease in scale numbers only in the cities where Horse Chestnut Scales have been observed first in Germany. On the other hand, almost every place located further away from these infestation sites showed a population increase ofP. regalis. Constant infestation levels over the past three years could be found in only two cities. In most cases lime, maple and horse chestnut trees were the host plants of this scale insect.     

Survey on the distribution of the Horse Chestnut ScalePulvinaria regalisCanard (Hom., Coccidae) in Germany in the years 1996 to 1998

In the present study, the distribution of the Horse Chestnut Scale insectPulvinaria regalis Canard in Germany in the years 1996 to 1998 and tendencies in the variation of infestation levels during the past three years were investigated by a survey. A questionnaire was sent to the offices for green areas and environmental affairs of 121 cities in Germany with a population exceeding 75.000 citizens. Additional observations by the authors were also taken into consideration. A comparison to data from 1995 was conducted. In the year 1998, this arboricultural pest occurred in 34 cities (15 in 1995) and could be found in the areas of the Rhineland and the Ruhr-Valley, from Bonn in the south up to Münster (Westphalia) in the north and from Aachen in the west to Hagen and Dortmund in the east.P. regalis could also be detected in Offenbach and Frankfurt a. M., It also occurred southward along the rivers Rhine and Neckar in the cities of Mainz, Ludwigshafen, Freiburg and Stuttgart. The most southern point whereP. regalis was detected in July 1998 was Zürich in Switzerland. The first occurrence of the 19 new observed infestations withP. regalis took place in six instances before 1995, eight in 1995, three in 1996, and one each in 1997 and 1998. The investigations about tendencies in the variation of infestation levels revealed a decrease in scale numbers only in the cities where Horse Chestnut Scales have been observed first in Germany. On the other hand, almost every place located further away from these infestation sites showed a population increase ofP. regalis. Constant infestation levels over the past three years could be found in only two cities. In most cases lime, maple and horse chestnut trees were the host plants of this scale insect.     

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.     

Spread modelling: a suitable tool to explore the role of human-mediated dispersal in the range expansion of the yellow-legged hornet in Europe

Abstract

Invasive species can spread locally on their own and can be introduced at long distance by humans. Here, we show how a spread model can be used to explore the role of humans in the range expansion of the invasive yellow-legged hornet, Vespa velutina nigrithorax, in Europe with a special focus on some islands. In 2017, the hornet distribution in France, southern Belgium, south-eastern Germany and northern Spain could largely be explained by the insect’s own dispersal while the occurrence in Portugal, Italy, the Netherlands and Great Britain likely results from human-mediated dispersal. However, in the following years, it could spread to Portugal, Italy and Great Britain also by its own means. The yellow-legged hornet has likely reached the Channel Islands by its own flight but it could hardly reach the Mediterranean islands. Hence, the infestation in Majorca likely results from an accidental introduction. When simulating human-mediated dispersal in the Mediterranean islands, the hornet density would remain relatively low anyhow. Assessing the means of dispersal is important in terms of pest management as the target is either to reduce the spread rate and the population density, or to reduce the risk of entry.     

Breeding for resistance: breeding for resistance to Plum pox virus in Italy

Plum pox virus (PPV) resistance in apricot and peach in Italy has been researched in several Italian institutions, including the Institutes for Fruit Tree Culture and Plant Pathology in Rome, which are assessing resistance, and the Universities of Bari, Bologna and Milan, examining breeding techniques, both by cross-breeding and genetic transformation approaches. A reliable protocol for resistance assessment has been set up, in which biological indexing, ELISA and PCR techniques are used. No source of resistance has yet been found in peach. Hybridization with Prunus davidiana could be investigated given the promising results obtained within the INRA programme in France. Almost 6000 apricot seedlings from controlled crosses between resistant parents have been investigated in search of possible molecular markers, but no positive results have been obtained so far, probably due the fact that resistance to both D and M strains is sought. The transformation of cultivars has proven difficult in apricot where the regeneration step is particularly critical, while in peach a reliable regeneration protocol still remains to be set up.     

A new aggressive strain of Verticillium albo-atrum in Verticillium resistant cultivars of tomato in the Netherlands

In 1991 serious losses caused byVerticillium wilt were found on two holdings in the Westland glasshouse district in the Netherlands in which theVerticillium resistant tomato cultivars Calypso and Criterium were grown in soilless systems. Isolates from diseased plants were identified asVerticillium albo-atrum.In inoculation experimentsVerticillium resistant tomato cultivars were seriously affected by the new isolates but not by a control isolate. Moneydor, a susceptible cultivar without the Ve gene, was the most seriously diseased by all isolates. The isolates from theVerticillium resistant tomato cultivars were less virulent on the susceptible cultivar than the control isolate.     

Public awareness: a useful tool for the early detection and a successful eradication of the longhorned beetles Anoplophora chinensis and A. glabripennis

Anoplophora chinensis and A. glabripennis, two longhorned beetles, are natives of Asia and are considered some of the most dangerous woodborers worldwide. Their infestations often go undetected for several years, allowing both species to colonize new areas undisturbed and reach population levels which are difficult to eradicate. In Italy, A. chinensis was first detected in 2001 near Milan, and in over a decade the Lombardy Plant Protection Service (PPS) has developed enough experience to contain this xylophagous pest. Thanks to these efforts, the Lombardy PPS staff realized that public awareness is pivotal for a successful and effective eradication program. Since the beginning of the infestation, the Lombardy Region has mounted a notable campaign of information through communication media designed to inform residents of the problem. The tools used have yielded interesting results.     

Resistance testing and the effectiveness of difenacoum against Norway rats (Rattus norvegicus) in a tyrosine139cysteine focus of anticoagulant resistance,Westphalia, Germany

BACKGROUND: Anticoagulant resistance in Norway rats at foci in Belgium, Denmark, France, Germany, the Netherlands and the United Kingdom is genetically characterised by the same single nucleotide polymorphism (SNP) and consequent amino acid exchange from tyrosine to cysteine at location 139 of the vkorc1 gene (i.e. tyrosine139cysteine or Y139C). The purpose of this study was to assess the degree of resistance among rats at two infested farm sites in the Y139C focus in Westphalia, Germany, using blood clotting response (BCR) tests, and to determine the practical efficacy of applications of a commercial 50 ppm difenacoum bait (Neokil^?) against them. RESULTS: BCR tests showed that the difenacoum resistance factor (RF) among the Y139C rats was about 2.5. DNA analysis for the Y139C mutation revealed that it was present among rats at the two sites with a prevalence of 75 and 93%. Applications of difenacoum bait at the two sites achieved 86.8 and 59.9% control. The different outcomes did not appear to be due to differences either in the degree and prevalence of resistance or in the quantities of poisoned bait consumed. CONCLUSION: The study showed that, although the RF for difenacoum among rats carrying the Y139C SNP was apparently low, an acceptable level of control of resistant Norway rat infestations was not achieved using difenacoum. Continued use of anticoagulants against rats that are resistant to them will exacerbate resistance problems in terms of both increased severity and prevalence. These conclusions are likely to apply elsewhere in Europe where the Y139C SNP occurs. Copyright © 2012 Society of Chemical Industry     

Is terrestrial plant import from East Asia into countries in the EPPO region a potential pathway for new emerging invasive alien plants?

Pathway analysis represents an effective means of identifying emerging invasive alien species. For plants, a significant number of invasions have been caused by plant species originally voluntary introduced as ornamentals. The pathway analysis for terrestrial ornamental plants imported from East Asia has been undertaken to provide information on the imports and to identify emerging terrestrial invasive alien plants. Data for terrestrial ornamental plants imported from East Asia into Austria, France, Italy, the Netherlands and Turkey was assembled at the genus level. Thousands of species of plants for planting are imported from East Asia in very large volumes. However, despite the fact that the data could only been analyzed at the genus level, it is considered that only a very limited number of taxa would become invasive. The potentially invasive alien species are already widely available in European nurseries and are principally produced within the European Union.     

Multilocus sequence typing reveals the presence of three distinct flavescence dorée phytoplasma genetic clusters in Croatian vineyards

Flavescence dorée phytoplasma (FDp) is a quarantine pathogen associated with a severe and epidemic grapevine yellows disease representing a great threat for grapevine cultivation in Europe. An increase in disease spread prompted efforts to identify FDp strains in Croatia. Over 800 samples of grapevine together with presumed reservoir plants and almost 400 samples of Scaphoideus titanus and other potential vectors were collected countrywide and analysed. FDp isolates were characterized by multilocus sequence typing (MLST) of map, secY and uvrB-degV genes in order to determine genetic diversity and structure of FDp populations, and to trace transmission pathways. FD-related phytoplasmas were found in Croatia for the first time in alder, the invasive tree species Ailanthus altissima and leafhopper Phlogotettix cyclops. Phylogenetic analysis revealed the presence of three mapFD strain clusters: mapFD1, mapFD2 and mapFD3, and for the first time in Croatia a case of Palatinate grapevine yellows strain A (PGY-A). In total, 7 different map, 10 secY and 11 uvrB-degV genotypes were detected. The identification of 15 comprehensive FDp genotypes based on MLST suggests separate routes for disease introduction and propagation origins in Croatia. Moreover, high genetic variability of Croatian isolates indicates a complex ecological cycle of FDp involving various hosts.     

Spread of proso millet (Panicum miliaceum L.) in Ontario, Canada. I. Rate of spread and crop susceptibility

The infestations of two biotypes of Panicum miliaceum L. were monitored over a 5-year period (1981–1985) as they occurred in two townships in southwestern Ontario, Canada. On average, 16·5% of the cultivated fields in Hullett township were infested with the black-seeded biotype while 12·9% of the fields in North Norwich township were infested with the golden-seeded biotype. Neither population showed clear signs of increasing. The two biotypes were similar in their ability to persist as adult infestations. The black-seeded biotype showed a greater potential for colonizing uninfested fields. The crops grown in this region showed different susceptibilities to infestation by P. miliaceum. Corn (maize) fields were susceptible while most grain fields were resistant to infestation. White beans were susceptible to infestation by the black-seeded biotype. Wheat and oat crops were more resistant to infestation by the golden-seeded biotype than to those of the black-seeded biotype.     

Integrated management of Thrips tabaci (Thysanoptera: Thripidae) on onion in north‐western Italy: basic approaches for supervised control

BACKGROUND: Thrips tabaci Lindeman (Thysanoptera: Thripidae) is a major pest on onion, Allium cepa L., worldwide. In 2010, research was conducted in a commercial onion field in north‐western Italy in order (i) to evaluate the efficacy of different insecticides and of the SAR activator acibenzolar‐S‐methyl, (ii) to correlate thrips infestation levels with bulb size and weight at harvest and (iii) to implement a reliable thrips sampling method. Efficacy of the three active ingredients spinosad, lambda‐cyhalothrin and acibenzolar‐S‐methyl on local thrips populations were also evaluated in laboratory bioassays. RESULTS: During field surveys, the highest and the lowest thrips infestations were observed in plots treated with lambda‐cyhalothrin and with spinosad and acibenzolar‐S‐methyl respectively. The effectiveness of spinosad was also confirmed in laboratory bioassays. At harvest, bulb size and weight did not significantly differ between treatments. A high correlation with visual inspection made plant beating a suitable sampling method for routine practice, enabling a good estimate of thrips infestation. CONCLUSION: Damage caused by thrips is often not severe enough to warrant the frequent pesticide applications the crops receive in north‐western Italy. The use of spinosad and acibenzolar‐S‐methyl is suggested as an alternative to conventional insecticides for the preservation of natural enemies. Copyright © 2011 Society of Chemical Industry     

Zucchini yellow mosaic virus; two outbreaks in the Netherlands and seed transmissibility

In 1983 and 1987/88 two limited outbreaks of zucchini yellow mosaic virus in cucumber and zucchini squash occurred in the Westland glasshouse district in the Netherlands, mainly in glasshouses. The disease could be eradicated and has not recurred so far. In both cases a relatively mild but still highly pathogenic strain of the virus was involved. Diseased plants of zucchini yielded severely distorted or no fruits and it was difficult to obtain seeds from infected plants. Two out of 4196 seedlings grown in isolation from seed from inoculated zucchini plants showed symptoms and contained the virus, indicating that the virus can be transmitted via seed but at very low rate. This explains the erratic incidence and international distribution of the virus.     

Response of UK winter wheat cultivars to <Emphasis Type="Italic">Soil-borne cereal mosaic</Emphasis> and <Emphasis Type="Italic">Wheat spindle streak mosaic viruses</Emphasis> across Europe.

Twenty-one UK winter wheat cultivars were grown over three seasons at sites with natural inoculum sources of Soil-borne cereal mosaic virus (SBCMV) and Wheat spindle streak mosaic virus (WSSMV) located in France, Italy and the UK. Plants were assessed visually for virus symptoms and leaf extracts were tested for the presence of each virus using enzyme-linked immunosorbent assays (ELISA). Cultivars showing little or no foliar symptoms and low levels of virus in leaf tissue were classified as resistant to each virus. All the trials were taken to harvest and agronomic data collected. At the most heavily infected sites, severe symptoms of SBCMV were observed in all UK cultivars except Aardvark, Charger, Claire, Cockpit, Hereward and Xi 19. The latter cultivars exhibited either light or no symptoms and little or no SBCMV infection in leaves. In fields with WSSMV, the virus failed to develop in Italy, but was detected in the leaves of all the susceptible control cultivars at a site in France. However, no UK cultivar tested positive for WSSMV. Multi-site analysis indicated that the presence of WSSMV did not increase the impact of SBCMV on the height, thousand-grain weight or yield of UK cultivars. The wheat cultivars on test gave a similar response to SBCMV across three European countries. Possible sources of SBCMV resistance are discussed.     

First report of Thrips setosus in Belgium

The Japanese flower thrips, Thrips setosus, is a polyphagous insect which in Europe has mainly been observed on hydrangeas (Hydrangea spp.). The first report of T. setosus in the EPPO region was in the Netherlands (2014). Since then it has been observed in four other countries inside the EPPO region: Germany (2015), the United Kingdom (2016), France (2016) and Croatia (2016). Its dispersal is most likely to be related to trade. Because of its polyphagous nature, there is a risk of spread to other economically important crops. Therefore, T. setosus was included in the national survey project ‘STATREGO’, during which the status of several invasive plant pests and diseases in Belgium was determined.     

The use of infrared spectroscopy and machine learning tools for detection of Meloidogyne infestations

Plant parasitic nematodes are generally soilborne pathogens that attack plants and cause economic losses in many crops. The infested plants show nonspecific symptoms or, often, are symptomless; therefore, diagnosis is performed by taking soil and root tissue samples. Here, we show that a combination of different infrared spectra analysis and machine learning algorithms can be used to detect plant parasitic nematode infestations before symptoms become visible, using leaves instead of roots and soil as samples. We found that tomato and guava plants infested with Meloidogyne enterorlobii produced different spectral patterns compared to uninfested plants. Using partial spectra from 1,450 to 900/cm as the "fingerprint region", principal component analyses indicated that after 5 (tomatoes) or 8 weeks (guava), plants with no visible symptoms of infestations were positively diagnosed. To improve the early detection response, we used machine learning modelling. A support vector machine (SVM) was used to obtain more robust, accurate models. The SVM model contained 34 support vectors, 17 for each level. The overall performance of the model was >97% and the total accuracy was significantly higher, demonstrating the absence of chance prediction. The best prediction of infestation was obtained at the second and fourth weeks for tomatoes and guavas, respectively, reducing the diagnostic time by half. The combined application of these techniques reduces the processing time from field to laboratory and shows enormous advantages by avoiding root and soil sampling.     

Occurrence of Mirafiori Lettuce Virus and Lettuce Big-vein Virus in Relation to Development of Big-vein Symptoms in Lettuce Crops

Big-vein disease (BV) of lettuce has been attributed to infection by Lettuce big-vein virus (LBVV), vectored by the soil fungus Olpidium brassicae. The finding of a second soil-borne virus in lettuce, Mirafiori lettuce virus (MiLV), led to a re-investigation of the role of LBVV in big-vein disease, with evidence emerging that both MiLV and LBVV are vectored by O. brassicae, and that MiLV, not LBVV, is the cause of BV (Lot et al. (2002), Phytopathology 92: 288–293). The two viruses have coat proteins of similar size but have different morphologies and are serologically unrelated. We tested individual lettuce plants in BV-prone fields and protected crops in France and Italy for the presence of the two viruses, using DAS-ELISA and antisera specific for each virus. Both MiLV and LBVV were found at high incidence, often together but sometimes separately. Symptoms were frequently found to be associated with MiLV alone or both viruses, but rarely LBVV alone. However, no absolute correlation emerged, because sometimes MiLV was present in the absence of symptoms, and vice versa. To clarify the situation, individual lettuce plants were examined over a period of time in two further surveys. In surveys of protected crops in France, plants with big-vein were always ELISA-positive for MiLV, or else symptomless plants positive for MiLV were later seen to develop big-vein symptoms. Presence or absence of LBVV appeared to have no effect on symptom development. In surveys of open fields in Italy, all combinations were found: presence of both viruses, apparent absence of both viruses, or presence of each one alone, in plants that developed BV. At the end of the observation period, nearly all plants had BV and contained both viruses.