The Teagasc Horticultural Development Unit (HDU) was established in 2005 as an integrated research and advisory unit. The HDU provides advice, training and research on horticultural related matters. The HDU is grouped into four enterprise teams with support from colleagues in the Teagasc colleges. Production of fruit and vegetables is a significant entity within the overall agricultural industry, making an important economic contribution in terms of supplying the domestic market, employment and foreign trade. The horticulture and potato sectors contributed approx €360m to farm output in 2008.

Recent Submissions

  • Exposure of Agaricus bisporus to Trichoderma aggressivum f. europaeum leads to growth inhibition and induction of an oxidative stress response

    Kosanovic, Dejana; Grogan, Helen; Kavanagh, Kevin; Irish Research Council; GOIPD/2018/115 (Elsevier BV, 2020-09)
    Green mould disease of mushroom, Agaricus bisporus,is caused by Trichodermaspecies and can result in substantial crop losses.Label free proteomic analysis of changes in the abundance of A. bisporusproteins following exposure to T. aggressivumsupernatantin vitroindicated increased abundance of proteins associated with an oxidative stress response (zinc ion binding (+6.6 fold); peroxidase activity (5.3-fold); carboxylic ester hydrolase (+2.4 fold); dipeptidase (+3.2 fold); [2Fe-2S] cluster assembly (+3.3 fold)). Proteins that decreased in relative abundance were associated with growth: structural constituent of ribosome, translation (-12 fold), deadenylation-dependent decapping of nuclear-transcribed mRNA (-3.4 fold), and small GTPase mediated signal transduction (-2.6 fold). In vivoanalysis revealed that 10-4 T. aggressivuminoculum decreased the mushroom yield by 29% to 56% and 10-3 T. aggressivuminoculum decreased the mushroom yield by 68% to 100%. Proteins that increased in abundance in A. bisporusin vivofollowing exposure to T. aggressivumindicated an oxidative stress response and included proteins with pyruvate kinase activity (+2.6 fold) and hydrolase activity (+2.1 fold)). The results indicate that exposure of A. bisporusmycelium to T. aggressivum in vitroand in vivoresulted in an oxidative stress response and reduction in growth.
  • A comparative study on seed physiology and germination requirements for 15 species of Eucalyptus

    Afroze, Farhana; Douglas, Gerry C.; Grogan, Helen; Department of Agriculture, Food and the Marine; 15/S/759 (Springer Science and Business Media LLC, 2021-09-23)
    Seed physiology of 15 Eucalyptus species of interest for cut foliage plantations was unknown and therefore evaluated. The viability and vigour of seeds and germination potential of 15 Eucalyptus species was determined by using a tetrazolium (TZ) staining test, and the results were compared to a germination test. In a separate experiment, seeds of each lot were subjected to either 0 or 4-week cold stratification at 4 ± 1 °C to investigate their potential stratification requirement. After stratification, seeds were then allowed to germinate at 22 ± 1 °C with 16 h lighting per day for 36 days. Seed viability and vigour were checked by evaluating % root, cotyledon and first true leaves emergence, and the speed of emergence, in the germination test. The germination percentages varied with the species. Seed stratification with the interaction of seed species lots significantly affected both viability and vigour. The seed viability of the different species ranged from 9 to 100% and 2 to 100%, for the TZ test and germination test, respectively, with a high correlation (R2 = 0.89) between the two. Physiology tests revealed that cold stratification of seed was not required for the 15 species to maximise their germination potential and growth in Irish and British climate.
  • Prunus laurocerasus - A crop walkers guide to pests and diseases

    Horticulture Development Department; Grogan, Helen; McGuinness, Brian; Whelton, Andy; Baars, Jan-Robert; Department of Agriculture, Food and the Marine; 15S759 (Teagasc, 2021)
    The large glossy leaves of Prunus laurocerasus are affected by a variety of problems including pests, diseases and nutrition. The most common issue is commonly referred to as ‘shothole’ due to the nature of the disease symptoms and its’ resemblance to shotgun damage. The causal agents of ‘shothole disease’ vary considerably and this will affect how you approach your disease management strategy.
  • Fertiliser characteristics of stored spent mushroom substrate as a sustainable source of nutrients and organic matter for tillage, grassland and agricultural soils

    Velusami, B.; Jordan, S.N.; Curran, T.; Grogan, Helen; Teagasc Walsh Scholarship Programme (Teagasc, 2021-05-12)
    Spent mushroom substrate (SMS) is an organic manure that can be used with advantage in agriculture. Under European Union (EU) (Good Agricultural Practice for Protection of Waters) Regulations, SMS cannot be applied to land over the winter months and must be stored on concrete surfaces, either covered or uncovered, to prevent nutrient-rich runoff seeping into groundwater. Spent mushroom substrate at four storage facilities, two covered and two uncovered, was analysed for physical and chemical characteristics after storage for up to 12 mo. Significant differences (P<0.05) were identified for all parameters across the four sites, except for pH, but there were no consistent differences that correlated with uncovered or covered storage conditions. The content of nitrogen (N) and manganese (Mn) was significantly lower in uncovered SMS, while the content of iron (Fe) and copper (Cu) was significantly higher. The chemical nitrogen-phospous-potassium (NPK) fertiliser equivalent value of SMS, when applied at a rate of 10 t/ha, was between €105 and €191 per hectare. Nitrogen-phospous-potassium concentrations per kg wet weight were all higher in SMS that was stored under cover, meaning higher chemical fertiliser savings are possible. The high pH of stored SMS (7.8–8.1) means it could be used with good effect on acid soils instead of ground limestone. The low bulk density of SMS (0.545–0.593 g/cm3) makes it an ideal amendment to soils to improve soil structure and quality. There is some variability in the nutrient content of SMS from different sources, so it is advisable to get the material analysed when including in nutrient management plans.
  • Tackling mushroom disease control in an environmentally conscious world

    Grogan, Helen (2021)
    The mushroom industry, like all of agriculture worldwide, is facing the impact of climate change as well as consumers’ desires to address it though modifying what they purchase so as to be as environmentally friendly as possible. At the 2021 ISMS Congress, Dr. Helen Grogan presented the state of the changing climate and opportunities for Integrated Pest Management in the mushroom industry.
  • First Report of Shot Hole Disease on Cherry Laurel (Prunus laurocerasus) Caused by Micrococcus aloeverae in Ireland

    Smith, L.; Gibriel, H. A. Y.; Brennan, C.; del Pino de Elias, M.; Twamley, A.; Doohan, F.; Grogan, Helen; Feechan, A.; Department of Agriculture, Food and the Marine; 15/S/759 (American Phytopathological Society, 2020-08-13)
    First Report of Shot Hole disease on Cherry Laurel (Prunus laurocerasus) Caused by Micrococcus aloeverae in Ireland
  • Exposure of Agaricus bisporus to Trichoderma aggressivum f. europaeum leads to growth inhibition and induction of an oxidative stress response

    Kosanovic, Dejana; Grogan, Helen; Kavanagh, Kevin; Science Foundation Ireland; Irish Research Council; 12/RI/2346.; GOIPD/2018/115 (Elsevier, 2020-07-23)
    Green mould disease of mushroom, Agaricus bisporus,is caused by Trichodermaspecies and can result in substantial crop losses.Label free proteomic analysis of changes in the abundance of A. bisporusproteins following exposure to T. aggressivumsupernatantin vitroindicated increased abundance of proteins associated with an oxidative stress response (zinc ion binding (+6.6 fold); peroxidase activity (5.3-fold); carboxylic ester hydrolase (+2.4 fold); dipeptidase (+3.2 fold); [2Fe-2S] cluster assembly (+3.3 fold)). Proteins that decreased in relative abundance were associated with growth: structural constituent of ribosome, translation (-12 fold), deadenylation-dependent decapping of nuclear-transcribed mRNA (-3.4 fold), and small GTPase mediated signal transduction (-2.6 fold). In vivoanalysis revealed that 10-4 T. aggressivuminoculum decreased the mushroom yield by 29% to 56% and 10-3 T. aggressivuminoculum decreased the mushroom yield by 68% to 100%. Proteins that increased in abundance in A. bisporusin vivofollowing exposure to T. aggressivumindicated an oxidative stress response and included proteins with pyruvate kinase activity (+2.6 fold) and hydrolase activity (+2.1 fold)). The results indicate that exposure of A. bisporusmycelium to T. aggressivum in vitroand in vivoresulted in an oxidative stress response and reduction in growth.
  • Is urban growing of fruit and vegetables associated with better diet quality and what mediates this relationship? Evidence from a cross-sectional survey

    Mead, Bethan R.; Christiansen, Paul; Davies, Jessica A.C.; Falagán, Natalia; Kourmpetli, Sofia; Liu, Lingxuan; Walsh, Lael; Hardman, Charlotte A.; Global Food Security; Biotechnology and Biological Services Research Council; et al. (Elsevier, 2021-03-18)
    Urban agriculture (UA), the growing of fruits and vegetables in urban and peri-urban areas, may improve food security and access, public health and dietary quality on both a broad and personal scale. However, there is little research on the relationship between UA and diet, and potential mediating factors are also unclear. This study aimed to investigate if proximity to and engagement with UA is associated with better diet quality, and what accounts for this relationship. UK-based adults (N = 583, 69% Female) completed measures of proximity to and engagement with UA, perceived access to fruits and vegetables, health and ethical food choice motivations, connection with nature, psychological distress and dietary quality in an online survey. Participants were recruited from UA-related groups and the general public. Proposed relationships were analysed using a structural equation model. Greater proximity to and engagement with UA was associated with greater perceived access to fruits and vegetables, more health-related food choice motivations, more ethical-related food choice, feeling more connected with nature, and, surprisingly greater psychological distress. Furthermore, proximity to and engagement with UA was indirectly associated with better diet quality via health-, and ethical-related, food choice motivations. While the direct pathway between proximity to and engagement with UA and diet quality was not significant, UA is associated with better diet quality, partly via healthier and ethical food choice motivations. Upscaling UA may have benefits for dietary quality via these factors, and more research is needed to test causal relationships and understand these complex interactions.
  • Exposure of Agaricus bisporus to Trichoderma aggressivum f. europaeum leads to growth inhibition and induction of an oxidative stress response

    Kosanovic, Dejana; Grogan, Helen; Kavanagh, Kevin; Irish Research Council; Science Foundation Ireland; GOIPD/2018/115; 12/RI/2346 (Elsevier BV, 2020-09)
    Green mould disease of mushroom, Agaricus bisporus,is caused by Trichodermaspecies and can result in substantial crop losses.Label free proteomic analysis of changes in the abundance of A. bisporusproteins following exposure to T. aggressivumsupernatantin vitroindicated increased abundance of proteins associated with an oxidative stress response (zinc ion binding (+6.6 fold); peroxidase activity (5.3-fold); carboxylic ester hydrolase (+2.4 fold); dipeptidase (+3.2 fold); [2Fe-2S] cluster assembly (+3.3 fold)). Proteins that decreased in relative abundance were associated with growth: structural constituent of ribosome, translation (-12 fold), deadenylation-dependent decapping of nuclear-transcribed mRNA (-3.4 fold), and small GTPase mediated signal transduction (-2.6 fold). In vivoanalysis revealed that 10-4 T. aggressivuminoculum decreased the mushroom yield by 29% to 56% and 10-3 T. aggressivuminoculum decreased the mushroom yield by 68% to 100%. Proteins that increased in abundance in A. bisporusin vivofollowing exposure to T. aggressivumindicated an oxidative stress response and included proteins with pyruvate kinase activity (+2.6 fold) and hydrolase activity (+2.1 fold)). The results indicate that exposure of A. bisporusmycelium to T. aggressivum in vitroand in vivoresulted in an oxidative stress response and reduction in growth.
  • The Potential for Decision Support Tools to Improve the Management of Root-Feeding Fly Pests of Vegetables in Western Europe

    Collier, Rosemary; Mazzi, Dominique; Folkedal Schjøll, Annette; Schorpp, Quentin; Thöming, Gunda; Johansen, Tor J.; Meadow, Richard; Meyling, Nicolai V.; Cortesero, Anne-Marie; Vogler, Ute; et al. (MDPI AG, 2020-06-13)
    Several important vegetable crops grown outdoors in temperate climates in Europe can be damaged by the root-feeding larvae of Diptera (Delia radicum, Delia floralis, Chamaepsila rosae, Delia platura, Delia florilega, Delia antiqua). Knowledge of pest insect phenology is a key component of any Integrated Pest Management (IPM) strategy, and this review considers the methods used to monitor and forecast the occurrence of root-feeding flies as a basis for decision-making by growers and the ways that such information can be applied. It has highlighted some current management approaches where such information is very useful for decision support, for example, the management of C. rosae with insecticidal sprays and the management of all of these pests using crop covers. There are other approaches, particularly those that need to be applied at sowing or transplanting, where knowledge of pest phenology and abundance is less necessary. Going forward, it is likely that the number of insecticidal control options available to European vegetable growers will diminish and they will need to move from a strategy which often involves using a single ‘silver bullet’ to a combination of approaches/tools with partial effects (applied within an IPM framework). For the less-effective, combined methods, accurate information about pest phenology and abundance and reliable decision support are likely to be extremely important.
  • First Report of Shot Hole Disease on Cherry Laurel (Prunus laurocerasus) Caused by Micrococcus aloeverae in Ireland

    Smith, L.; Gibriel, H. A. Y.; Brennan, C.; del Pino de Elias, M.; Twamley, A.; Doohan, F.; Grogan, Helen; Feechan, A.; Department of Agriculture, Food and the Marine; 15/S/759 (Scientific Societies, 2020-08-13)
    First Report of Shot Hole Disease on Cherry Laurel (Prunus laurocerasus) Caused by Micrococcus aloeverae in Ireland
  • Is urban growing of fruit and vegetables associated with better diet quality and what mediates this relationship? Evidence from a cross-sectional survey.

    Mead, Bethan; Christiansen, Paul; Davies, Jessica; Falagán, Natalia; Kourmpetli, Sofia; Liu, Lingxuan; Walsh, Lael; Hardman, Charlotte; Global Food Security's ‘Resilience of the UK Food System Programme’; BBSRC; et al. (Elsevier, 2021-03-18)
    Urban agriculture (UA), the growing of fruits and vegetables in urban and peri-urban areas, may improve food security and access, public health and dietary quality on both a broad and personal scale. However, there is little research on the relationship between UA and diet, and potential mediating factors are also unclear. This study aimed to investigate if proximity to and engagement with UA is associated with better diet quality, and what accounts for this relationship. UK-based adults (N = 583, 69% Female) completed measures of proximity to and engagement with UA, perceived access to fruits and vegetables, health and ethical food choice motivations, connection with nature, psychological distress and dietary quality in an online survey. Participants were recruited from UA-related groups and the general public. Proposed relationships were analysed using a structural equation model. Greater proximity to and engagement with UA was associated with greater perceived access to fruits and vegetables, more health-related food choice motivations, more ethical-related food choice, feeling more connected with nature, and, surprisingly greater psychological distress. Furthermore, proximity to and engagement with UA was indirectly associated with better diet quality via health-, and ethical-related, food choice motivations. While the direct pathway between proximity to and engagement with UA and diet quality was not significant, UA is associated with better diet quality, partly via healthier and ethical food choice motivations. Upscaling UA may have benefits for dietary quality via these factors, and more research is needed to test causal relationships and understand these complex interactions.
  • The effect of Pulsed Electric Field as a pre-treatment step in Ultrasound Assisted Extraction of phenolic compounds from fresh rosemary and thyme by-products, Innovative Food Science and Emerging Technologies

    Tzima, Katerina; Brunton, Nigel P.; Lyng, James G.; Frontuto, Daniele; Rai, Dilip K.; Teagasc Walsh Fellowship Programme; 2016038 (Elsevier, 2021-02-22)
    Emerging extraction techniques, including pulsed electric field (PEF) and ultrasound (US), are attracting considerable interest in the recovery of bioactives. Though, limited work has focused on PEF application as pre-treatment for US assisted extraction to enhance the release of phenolics from herbs. Hence, the present study investigated the use of an optimized PEF pre-treatment to enhance the recovery of phenolics from fresh rosemary and thyme by-products in a subsequent US assisted extraction step. Total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) were assessed as an index of extraction efficacy. Qualitative and quantitative analyses were performed through liquid chromatography-mass spectrometry analyses to evaluate the influence of the methods on individual phenolic compounds and the formation of potential derivatives. The results indicated that in a number of cases PEF pre-treatment enhanced (p < 0.05) the recovery of phenolic compounds and antioxidant capacity compared to US individually.
  • Genetic regulation of compost and plant degradation mechanisms in Agaricus bisporus

    Dunne, Keith; O' Donoghue, Martin-Timothy; Grogan, Helen; Heneghan, Mary; IT Sligo; Department of Agriculture, Food and the Marine (2021-06-16)
    Agaricus bisporus (common button mushroom) is an economically significant mushroom with an annual global value in excess of $4.7 billion (Eastwood et al, 2015). When commercially grown, A. bisporus mushrooms are mostly picked from the first and second flush. This is due to the third flush resulting in reduced yields (Royse and Sanchez, 2008), which are also often more prone to disease. This occurs despite significant nutrients and nitrogen being available in the compost for A. bisporus to utilise. To further understand why this is occurring, microarray analysis was carried out on compost samples throughout a full commercial growth cycle, with the aim of identifying genes that may be responsible for this reduction in yield.
  • Proteomic investigation of interhyphal interactions between strains of Agaricus bisporus

    O’Connor, Eoin; Owens, Rebecca A.; Doyle, Sean; Amini, Aniça; Grogan, Helen; Fitzpatrick, David; Teagasc Walsh Fellowship Programme; Science Foundation Ireland; 10564231; SFI 12/RI/2346(3) (Elsevier BV, 2020-06)
    Hyphae of filamentous fungi undergo polar extension, bifurcation and hyphal fusion to form reticulating networks of mycelia. Hyphal fusion or anastomosis, a ubiquitous process among filamentous fungi, is a vital strategy for how fungi expand over their substrate and interact with or recognise self- and non-self hyphae of neighbouring mycelia in their environment. Morphological and genetic characterisation of anastomosis has been studied in many model fungal species, but little is known of the direct proteomic response of two interacting fungal isolates. Agaricus bisporus, the most widely cultivated edible mushroom crop worldwide, was used as an in vitro model to profile the proteomes of interacting cultures. The globally cultivated strain (A15) was paired with two distinct strains; a commercial hybrid strain and a wild isolate strain. Each co-culture presented a different interaction ranging from complete vegetative compatibility (self), lack of interactions, and antagonistic interactions. These incompatible strains are the focus of research into disease-resistance in commercial crops as the spread of intracellular pathogens, namely mycoviruses, is limited by the lack of interhyphal anastomosis. Unique proteomic responses were detected between all co-cultures. An array of cell wall modifying enzymes, plus fungal growth and morphogenesis proteins were found in significantly (P < 0.05) altered abundances. Nitrogen metabolism dominated in the intracellular proteome, with evidence of nitrogen starvation between competing, non-compatible cultures. Changes in key enzymes of A. bisporus morphogenesis were observed, particularly via increased abundance of glucanosyltransferase in competing interactions and certain chitinases in vegetative compatible interactions only. Carbohydrate-active enzyme arsenals are expanded in antagonistic interactions in A. bisporus. Pathways involved in carbohydrate metabolism and genetic information processing were higher in interacting cultures, most notably during self-recognition. New insights into the differential response of interacting strains of A. bisporus will enhance our understanding of potential barriers to viral transmission through vegetative incompatibility. Our results suggest that a differential proteomic response occurs between A. bisporus at strain-level and findings from this work may guide future proteomic investigation of fungal anastomosis.
  • Effectiveness of current hygiene practices on minimization of Listeria monocytogenes in different mushroom production‐related environments

    Pennone, Vincenzo; Dygico, Kenneth Lyonel; Coffey, Aidan; Gahan, Cormac G.M.; Grogan, Helen; McAuliffe, Olivia; Burgess, Catherine M.; Jordan, Kieran; Department of Agriculture, Food and the Marine; 14/F/881 (Wiley, 2020-05-20)
    Background: The commercial production of Agaricus bisporus is a three stage process: 1) production of compost, also called “substrate”; 2) production of casing soil; and 3) production of the mushrooms. Hygiene practices are undertaken at each stage: pasteurization of the substrate, hygiene practices applied during the production of casing soil, postharvest steam cookout, and disinfection at the mushroom production facilities. However, despite these measures, foodborne pathogens, including Listeria monocytogenes, are reported in the mushroom production environment. In this work, the presence of L. monocytogenes was evaluated before and after the application of hygiene practices at each stage of mushroom production with swabs, samples of substrate, casing, and spent mushroom growing substrates. Results: L. monocytogenes was not detected in any casing or substrate sample by enumeration according to BS EN ISO 11290-2:1998. Analysis of the substrate showed that L. monocytogenes was absent in 10 Phase II samples following pasteurization, but was then present in 40% of 10 Phase III samples. At the casing production facility, 31% of 59 samples were positive. Hygiene improvements were applied, and after four sampling occasions, 22% of 37 samples were positive, but no statistically significant difference was observed (p > .05). At mushroom production facilities, the steam cookout process inactivated L. monocytogenes in the spent growth substrate, but 13% of 15 floor swabs at Company 1 and 19% of 16 floor swabs at Company 2, taken after disinfection, were positive. Conclusion: These results showed the possibility of L. monocytogenes recontamination of Phase III substrate, cross-contamination at the casing production stage and possible survival after postharvest hygiene practices at the mushroom growing facilities. This information will support the development of targeted measures to minimize L. monocytogenes in the mushroom industry.
  • First evidence of retained sexual capacity and survival in the pyrethroid resistant Sitobion avenae (F.) (Hemiptera: Aphididae) SA3 super-clone following exposure to a pyrethroid at current field-rate

    Walsh, L.E.; Gaffney, Michael; Malloch, G.L.; Foster, S.P.; Williamson, M.S.; Mangan, R.; Purvis, G.; Department of Agriculture, Food and the Marine; Biotechnology and Biological Sciences Council of the United Kingdom; 14/s/879; et al. (Teagasc, 2019-04-17)
    The grain aphid Sitobion avenae is a prolific pest of cereal crops worldwide, controlled effectively with pyrethroid insecticides. However, the classic knock down resistance (kdr) mutation, L1014F on the S. avenae sodium channel gene, has been identified as the cause of the recently observed heterozygous (kdr-SR) resistance in the SA3 grain aphid super-clone. Results indicate that the kdr-SR SA3 clone can survive pyrethroid exposure above twice the normal field rate, continuing to reproduce thereafter. Additionally, the SA3 clone was found to be capable of producing sexual oviparous morphs, able to lay eggs following pyrethroid exposure. This demonstrates that possession of the L1014F mutation does not preclude the capacity to produce sexual morphs. This makes the adoption of an effective resistance management strategy imperative, within a wider integrated pest management (IPM) approach to control grain aphid.
  • Teagasc submission made in response to the Discussion document for the preparation of a National Policy Statement on the Bioeconomy

    Henchion, Maeve; Devaney, Laura; Caslin, Barry; Fenton, Owen; Fenelon, Mark; Finn, Sean; Finnan, John; Ní Fhlatharta, Nuala; Gaffney, Michael; Hayes, Maria; et al. (Teagasc, 2017-09-19)
    This document is Teagasc’s response to the “Discussion Document for the Preparation of a National Policy Statement on the Bioeconomy” issued by the Department of the Taoiseach’s Economic Division in July 2017. It recognises the potential significance of the bioeconomy to Ireland, offers some policy and strategic insights from other countries, and identifies Teagasc’s role in supporting the development of the bioeconomy in Ireland.
  • The ability of Listeria monocytogenes to form biofilm on surfaces relevant to the mushroom production environment

    Dygico, Lionel Kenneth; Gahan, Cormac G.M.; Grogan, Helen; Burgess, Catherine; Department of Agriculture, Food and the Marine; 14F881 (Elsevier, 2020-03-16)
    Due to its ubiquitous nature, Listeria monocytogenes is a threat to all fresh fruits and vegetables, including mushrooms, which are Ireland's largest horticultural crop. Although fresh cultivated mushrooms (Agaricus bisporus) have not been previously linked with listeriosis outbreaks, the pathogen still poses a threat to the industry, particularly due to its ability to form biofilms. This threat is highlighted by the multiple recalls of mushroom products caused by L. monocytogenes contamination and by previous studies demonstrating that L. monocytogenes is present in the mushroom production environment. In this study, the biofilm formation potential of L. monocytogenes strains isolated from the mushroom production environment was investigated on materials and at temperatures relevant to mushroom production. A preliminary assessment of biofilm formation of 73 mushroom industry isolates was undertaken using a crystal violet assay on polystyrene microtitre plates. The biofilm formation of a subset (n = 7) of these strains was then assessed on twelve different materials, including materials that are representative of the materials commonly found in the mushroom production environments, using the CDC biofilm reactor. Vertical scanning interferometry was used to determine the surface roughness of the chosen materials. All the strains tested using the CDC biofilm reactor were able to form biofilms on the different surfaces tested but material type was found to be a key determining factor on the levels of biofilm formed. Stainless steel, aluminium, rubber, polypropylene and polycarbonate were all able to support biofilm levels in the range of 4–4.9 log10 CFU/cm2, for seven different L. monocytogenes strains. Mushroom industry-specific materials, including growing nets and tarpaulins, were found to support biofilms levels between 4.7 and 6.7 log10 CFU/cm2. Concrete was found to be of concern as it supported 7.7 log10 CFU/cm2 of biofilm for the same strains; however, sealing the concrete resulted in an approximately 2-log reduction in biofilm levels. The surface roughness of the materials varied greatly between the materials (0.7–3.5 log10 Ra) and was found to have a positive correlation with biofilm formation (rs = 0.573) although marginally significant (P = 0.051). The results of this study indicate that L. monocytogenes can readily form biofilms on mushroom industry relevant surfaces, and additionally identifies surfaces of specific concern, where rigorous cleaning and disinfection is required.
  • First evidence of retained sexual capacity and survival in the pyrethroid resistant Sitobion avenae (F.) (Hemiptera: Aphididae) SA3 super-clone following exposure to a pyrethroid at current field-rate

    Walsh, L.E.; Gaffney, Michael; Malloch, G.L.; Foster, S.P.; Williamson, M.S.; Mangan, R.; Purvis, G.; Department of Agriculture, Food and the Marine; Biotechnology and Biological Sciences Council; Rural ̦ Environment Science ̦ Analytical Services Division of the Scottish Government; et al. (Teagasc, 2019-04-17)
    The grain aphid Sitobion avenae is a prolific pest of cereal crops worldwide, controlled effectively with pyrethroid insecticides. However, the classic knock down resistance (kdr) mutation, L1014F on the S. avenae sodium channel gene, has been identified as the cause of the recently observed heterozygous (kdr-SR) resistance in the SA3 grain aphid super-clone. Results indicate that the kdr-SR SA3 clone can survive pyrethroid exposure above twice the normal field rate, continuing to reproduce thereafter. Additionally, the SA3 clone was found to be capable of producing sexual oviparous morphs, able to lay eggs following pyrethroid exposure. This demonstrates that possession of the L1014F mutation does not preclude the capacity to produce sexual morphs. This makes the adoption of an effective resistance management strategy imperative, within a wider integrated pest management (IPM) approach to control grain aphid.

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