Fulltext search in archive

Myclobutanil is a chemical pesticide commonly used in the production of some vegetables and fruits like greenhouse peppers, grapes, and apples. The aim of this study was to investigate the genotoxic and cytotoxic effects of myclobutanil fungicide on the Allium cepa plant, the model organism. Randomly amplified polymorphic DNA and inter simple sequence repeat-PCR techniques were performed on the DNA of A. cepa exposed to the different myclobutanil doses and time periods. The nucleus anomalies and abnormal anaphases were investigated using a light microscope. PCR analyses showed that myclobutanil causes some DNA sequence changes on the onion genome depending on the increase in the fungicide dose and exposure time. It was determined that myclobutanil has a serious genotoxic effect, even in low doses like 25-50 ppm.

Sunflower downy mildew caused by Plasmopara halstedii (Farl.) Berl. et de Toni is a destructive and widespread disease. More than 50 races of P. halstedii have been recorded worldwide. In 2020, in the Russian Federation (Zernogradsky district, Rostov region), a globally new race 337 was identified for the first time. The pathogen was identified on the plants of a foreign sunflower hybrid bearing the resistance gene Pl₆. According to the five-digit racial nomenclature, its virulence profile was determined as 337 53. It is the first P. halstedii race recorded in the Russian Federation that simultaneously infects all differential lines of the 3^rd triplet, i.e., HA-R4, HA-R5 and HA-335. The sunflower lines RHA-274, 803-1, PSC8, RHA-419 and RHA-340 were resistant to it. All the collected isolates of the new race were susceptible to the fungicide mefenoxam.

Cryphalus asperatus (Coleoptera: Curculionidae, Scolytinae) is described as an exceptional but important secondary pest of Norway spruce seedlings. Of the 10 000 seedlings transported to one location in the Ore Mountains, Central Europe in 2020, in total 1 500 seedlings were killed by C. asperatus. The infestation and death of seedlings probably resulted in part from the substantial local increase in the local abundance of C. asperatus after the sanitation felling of many Ips typographus-infested and otherwise damaged trees; the felled trees provided many branches suitable for C. asperatus feeding. In addition, the seedlings were probably stressed by the multi-hour transportation (probably drought) from the forest nursery.

The double-spined bark beetle Ips duplicatus (Coleoptera: Curculionidae, Scolytinae) is an invasive forest pest having a broad range of coniferous hosts within Europe. We found this species to be also developing in the Serbian spruce Picea omorika. Ips duplicatus infested 14 (52%) of 27 P. omorika mature trees in an arboretum garden in northern Slovakia in Central Europe during the summer of 2019. Logs from the upper part of stems of P. omorika trees placed in eclectors in the laboratory, yielded a total of 179 individuals of three scolytine species, with prevalence of I. duplicatus. Our results show that I. duplicatus also colonized less likely host such as the Serbian spruce, causing threat to this ornamental tree and contributing to its mortality in urban habitats during hot and dry summer weather.

New techniques for Ceratitis capitata (Wiedemann, 1824) control are being studied and developed to replace traditional organophosphate pesticide applications. A mass trapping strategy offers promising medfly control within integrated pest management (IPM) programmes. Field assays were performed to study the efficacy of two mass trapping techniques based on PheroNorm^® and Ceratrap^® lures that were compared to a conventional approach to control the medfly in Tunisian apricot orchards. The results showed that both mass trapping techniques had a similar efficiency in reducing the C. capitata population. The degrees Brix in the fruits was a determinant issue since the initial apricot fruit damage was detected at 6.4%. At harvesting, the lowest fruit damage rate was recorded in the PheroNorm^® (4.25%) and Ceratrap^® (6.50%) treated orchards, compared with the conventional approach (10.75%). Therefore, the use of 50 PheroNorm^® and Ceratrap^® traps per ha density within an IPM approach may be very useful to control the C. capitata populations in apricot orchards.

The brown marmorated stink bug, Halyomorpha halys Stål, 1855 (Hemiptera: Heteroptera: Pentatomidae), is recorded from Slovakia for the first time based on a 5^th instar larva collected in the town of Štúrovo, Slovakia. The current distribution, economic importance and biology of the species are briefly reviewed. During the visit to Štúrovo, a mass occurrence of adults and larvae of the southern green stink bug, Nezara viridula (Linnaeus, 1758) (Pentatomidae), so far captured in Slovakia in 2014 only as a single specimen, was also observed. This observation confirms the presence of N. viridula as an established species in southern Slovakia. Both species are important pests to a large number of crops (vegetables, fruit trees, decorative plants, etc.) and can cause considerable economic losses.

In June 2018, the presence of one adult specimen and one egg cluster of the North-American oak lace bug Corythucha arcuata were recorded near the village of Mužla, close to the Danube River, in southern Slovakia. They were found on leaves of Quercus cerris growing in a mixed stand. In August 2018, other specimens (nymphs and adults) were observed on Quercus robur leaves, near Čičarovce, in eastern Slovakia. This is the first record of C. arcuata in our country. The oak lace bug probably reached us while invading from Hungary, where heavy infestation is reported from several parts of the country.

Damage by the blueberry gall midge Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) was found on different cultivars of highbush Vaccinium corymbosum L. at different localities of Lithuania. D. oxycoccana is a serious insect pest of blueberries in North America. In 1996, unusual damage on blueberries was observed in Europe. This is the first report of the blueberry gall midge occurrence in blueberry plantations in Lithuania.

After the first record of the banded greenhouse thrips, Hercinothrips femoralis (Reuter, 1891) in Slovakia in 2008, a peculiar occurrence in an extreme subalpine environment of Podbanské (High Tatra Mts.), Slovakia, during the summer of the same year was observed. Since this species of exotic thrips is known to be almost sedentary, the mode of dispersal was hypothesized to be related to passive transport via weather currents. According to our observations of unintentional dispersal a test was conducted to research a previously unidentified introduction pathway of this species. Our preliminary results show that passive transport by humans plays a crucial role in the dispersal of H. femoralis.

Key scale insects that have long been considered as having high economic importance in Tunisia and for which several research studies and pest management programs have been undertaken include the mealybug species Planococcus ficus (Signoret) and Planococcus citri Risso, the soft scale Saissetia oleae (Olivier) and the armoured scale Parlatoria ziziphi (Lucas). The host plants, bio-ecological aspects, auxiliary fauna of each of the aforementioned species as well as the related economic losses and pest management strategies adopted are explored and discussed. Among these species, P. ficus is considered herein as the most economically important in Tunisia. Still, the present contribution constitutes the first review article on key scale insects infesting plants in the South Mediterranean Maghreb area.

Damage caused by the Goji berry gall mite, Aceria kuko (Kishida, 1927) was observed on the leaves of Lycium chinense Miller (Solanaceae) in Brno in August 2016 and on L. barbarum L. in Popovice in September 2016. Aceria kuko is a pest of Asian origin which is common in China and occurs only sporadically on Goji berry plants in the European Union. This is the first observation of the Goji berry gall mite occurrence in the Czech Republic.

Botrytis cinerea, the causal agent of grey mould, is a predominant agent causing extensive postharvest and quality losses of apples in Tunisia and worldwide. Efforts to manage this disease have met with limited success. For this reason, the use of microorganism preparations to control fungal diseases as an alternative to fungicides became an urgent need. From a total of 60 epiphytic yeasts, 10 were assessed in vitro against B. cinerea and selected isolates showing antagonism were evaluated for their ability to suppress the grey mould in vivo. On Petri plates, the most promising strains (three strains of Aureobasidium pullulans, one Cryptococcus flavescens, and one Citeromyces matritensis) showed a zone of inhibition against the pathogen fungus not exceeding 10 mm. In vivo, these isolates showed a remarkable antifungal activity since they significantly reduced disease severity on apples from 63% to 95% compared to the control. In conclusion, the work has demonstrated that the three strains, L7 of Aureobasidium pullulans, L2 of Citeromyces matritensis, and L10 of Cryptococcus flavescens, were highly effective and can be used as potential biocontrol agents in controlling the post-harvest decay of apples caused by B. cinerea.

Prociphilus (Meliarhizophagus) fraxinifolii (Riley, 1879) (Hemiptera: Eriosomatidae) is an alien species in Europe that has been spreading quickly there. This paper presents the origin and current occurrence, classification, description, identification, and biology of this species. It also discusses the harmfulness and threats, especially the impact on host- plants and ecosystem, invasion rate and facilitating factors.

The first record of vanda thrips (Dichromothrips corbetti [Priesner, 1936], Thysanoptera, Thripidae) in Slovakia is presented. An economically important pest with heavy infestations on flowers of Phalaenopsis orchids was recorded as introduced most probably from North African plantations. Potential infiltration of this exotic species into Central European glasshouses refers to the globalisation of trade in biological commodities.

Using reverse transcription polymerase chain reaction, 160 sweet and sour cherry trees from a germplasm collection, orchards, and wild trees in the Czech Republic were screened for the presence of Cherry necrotic rusty mottle virus (CNRMV) and Cherry green ring mottle virus (CGRMV). The viruses were detected exclusively in sweet cherry trees in the germplasm collection, with CNRMV determined in two trees and CGRMV in four trees. Using next-generation sequencing, nearly complete genomic sequences (complete ORFs) were obtained for one CNRMV and three CGRMV isolates. Their relatedness to GenBank sequences of isolates from different countries together with negative results from screening outside of the germplasm collection suggests that the viruses had been imported with accessions.

Ditylenchus weischeri was recently reported in the provinces of Manitoba and Saskatchewan, Canada. Populations of D. weischeri from creeping thistle (Cirsium arvense L.) in Manitoba and D. dipsaci from garlic (Allium cepa L.) in Ontario were examined for their potential to grow on callused carrot (Daucus carota subsp. sativus) disks, alfalfa (Medi- cago sativa L.) and creeping thistle callus tissues, and pure cultures of eight fungal species, Botrytis cinerea, Fusarium solani, Rhizoctonia solani, Verticillium dahliae, Sclerotinia sclerotiorum, Cladosporium cucumerinum, Colletotrichum gloeosporioides, and Chaetomium spp. Ditylenchus weischeri and D. dipsaci could not be reared on any of the fungal isolates nor in the callus tissues of creeping thistle. In contrast to D. weischeri, D. dipsaci was successfully reared on the alfalfa callus tissue. On the callused carrot disks, with no media, an increase of 54 and 244 times the initial density of 80 nematodes was obtained for D. weischeri and D. dipsaci, respectively. Monoxenic rearing was performed using callused carrot disks to provide sufficient D. weischeri inoculum for the microplot study. The effect of D. weischeri on yellow pea varieties Agassiz and Bronco was determined in a microplot trial using initial densities of 0, 100, 200, 400, 800, 1600, and 3200 nematodes/plant. While it had no impact on pea grain yield, D. weischeri slightly reduced plant height, aboveground biomass, and pod length at the population densities of 1600 and 3200 nematodes/plant. The final population densities at harvest were not significantly different from the initial densities indicating the pea varieties were poor hosts to D. weischeri. The results of the present study indicate that D. weischeri is unlikely to be a pest of yellow pea for weather conditions of the Canadian Prairies.

Winter oilseed rape is the second most frequently grown crop in the Czech Republic. Clubroot, caused by Plasmodiophora brassicae (Wor.), was previously a problem in production of vegetable. The disease has been spreading on winter rape (Brassica napus L.) over the past four years. Infected stands were reported throughout the country in autumn 2011. The pathogen is probably widely spread in the whole country, its incidence depends on suitable weather conditions. Every field with clubroot is considered as contaminated for many years. The amounts of inoculum and its distribution are not sufficient yet, but this is just the initial stage of colonisation. There is a similar situation resembling experiences from other countries (Canada, Germany) where clubroot has gradually expanded in the last 15 years.

The tulip tree aphid, Illinoia liriodendri, is reported in Slovakia for the first time. Colonies of I. liriodendri were found on tulip trees, Liriodendron tulipifera, in two locations of south-western Slovakia in 2014 and 2015. Colonies of nymphs and viviparous females fed on the underside of leaves with no significant symptoms of damage to tulip trees. In this short study, the first report of the aphid from Slovakia is presented and original illustrations with results of morphometric analysis of alate viviparous females are provided.

Commercialisation of Biotech/GM (Biotech) crops started in 1995. Not only field crops, but also horticultural transgenic crops are under development and are beginning to be commercialised. Genetic engineering has the potential to revolutionise fruit tree breeding. The development of transgenic fruit cultivars is in progress. Over the past 20 years an international public sector research team has collaborated in the development of HoneySweet plum which is highly resistant to Plum pox virus (PPV) the most devastating disease of plums and other stone fruits. HoneySweet was deregulated in the USA in 2010. HoneySweet (aka C5) has been evaluated for eleven years (2002-2012) in a regulated field trial in the CzechRepublic for the resistance to PPV, Prune dwarf virus (PDV), and Apple chlorotic leaf spot virus (ACLSV), all of them being serious diseases of plum. Even under the high and permanent infection pressure produced through grafting, PPV has only been detected in HoneySweet trees in several leaves and fruits situated close to the point of inoculum grafting. The lack of infection spread in HoneySweet demonstrates its high level of PPV resistance. Co-infections of PPV with PDV and/or ACLSV had practically no influence on the quantity and quality of HoneySweet fruit which are large, sweet, and of a high eating quality. In many respects, they are superior to the fruits of the well-known cultivar Stanley. Many fruit growers and fruit tree nurseries in the CzechRepublic are supportive of the deregulation of HoneySweet plum to help improve the plum production and control the spread of PPV.

Silvertop is a serious disease of grasses, and severe infestations cause a great deal of damage every year (particularly to seed producers). Inflorescences of infected plants dry prematurely and are sterile. The genera Festuca, Poa, Agrostis, Trisetum, and Cynosurus are the most frequent hosts of this disease, which has newly been reported in a loloid-type intergeneric Festulolium hybrid. The disease was also observed in the genus Lolium, with only rare previous description. The suspicion that Fusarium poae is the causal agent of severe silvertop was confirmed, and the pathogen was morphologically described and confirmed by molecular analysis. The meadow plant bug (Leptopterna dolabrata) may be a vector transferring the pathogen to plants, although a direct pathogen transfer was not demonstrated. Grass colonisation by the pathogen therefore apparently occurs after plant tissues injury by sucking of the meadow plant bug.

Sugarcane plant samples affected by the disease pokkah boeng were collected from the major sugarcane producing areas in Iran. Fifty isolates of Fusarium verticillioides were recovered from diseased sugarcanes. Results of pathogenicity tests revealed that all isolates were pathogenic to sugarcane. Four hundred and eighty-five nitrate non-utilising mutants were generated from F. verticillioides isolates. Media used for nit mutant generation included potato dextrose agar, minimal medium and Czapeck agar amended with 1.8%, 2%, 2.5%, and 3% potassium chlorate. Nit mutants were divided into three phenotypic (nit1, nit3, and nitM) classes based on their growth on different nitrogen sources in the culture media. Among the isolates tested, 280, 115 and 90 nit1, nit3, and nit M were generated, respectively. Nit mutants were used to force the heterokaryon formation to determine the distribution of VCGs and their relation to pathogenicity and geographic origin. Forty-eight VCGs of F. verticillioides were isolated from sugarcane. Forty-six of the VCGs were represented by a single isolate, whereas the remaining two comprised two isolates. None of the VCGs was common.

The acute and chronic toxicity to honeybees, Apis mellifera of water guttation and dew collected from winter rape plants treated with the insecticide Nurelle D^® (a.i. chlorpyriphos + cypermethrin) was investigated. Caged bees were fed on sugar syrup containing water guttation and dew for 24 h (acute toxicity test) and for 10 days (chronic toxicity test). Bee mortality and food consumption were determined daily. A contact toxicity test was performed within 24 h on bees kept in Petri dishes (10 bees per dish) lined with filter paper saturated with the test solution. The acute Nurelle D^® contact and oral toxicity tests showed that the mortality of bees treated with water guttation and dew collected from the treated plants did not exceed 10%. A chronic toxicity test showed that adding contaminated water guttation and dew to the syrup caused an insignificant increase in bee mortality and reduced the syrup consumption significantly. The chlorpyriphos residue found in contaminated water guttation and dew were below the limit of detection (0.8 µg/kg) and the cypermethrin residue was below the detection levels.

An outline of past achievements in plant pathology in the CR and main recent problems of Czech plant pathologists are given. A description of the present state in plant pathology in the CR is preceded by data on the structure of CR, on its agriculture, research and development. The outstanding feature of the Czech agriculture is large-scale production. However, the CR still lags behind the EU in yields per hectare. Compared with the EU member states, the CR devotes less money (less then 0.7% of GDP) to research and development (R&D). The trend of state subsidies to R&D in the agriculture sector in current prices is stagnant. It represents an actual decline in the fixed prices. In the Czech Republic, approximately six hundreds persons are professionally engaged in plant health. It represents 6 professionals per 100 hundreds citizens in the CR. Around 160 persons deal with the research and/or teaching of plant pathology. Public service in the field of plant health (advisory work, extension or outreach activities) is one of the weak links in the system of plant health care in the CR. The reason is the lack of commitment for this field of plant health care activity together with absence of sufficient financial support. Minimum requirements for education should be set on advisors and provider of services in the field of plant health at the EU level. In the CR, there exists still some gap in scientific expertise of nematology and integrated pest management. The Czech Lands are proud of the role of some Bohemian and Moravian scientists who have been prominent in the development of plant pathology and related disciplines. These include: AUGUSTUS CARL JOSEPH CORDA and FRANTIŠEK BUBÁK in mycology, GREGOR JOHANN MENDEL in genetics, FRANTIŠEK KRÁL in bacteriology, BOHUMIL NĚMEC and EDUARD BAUDYŠ in plant pathology.