• 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.
    • 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.
    • 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
    • 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
    • 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.
    • 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.
    • 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.