Visible Mold Research Articles

Occurrence of Mycotoxins in Grass and Whole-Crop Cereal Silages—A Farm Survey

Mycotoxin incidence in forage may heavily affect the amount of toxins consumed by cattle. However, many studies have focused on mycotoxin occurrence in cereals and there are less studies of forages, particularly of grass silages. For determining the occurrence of mycotoxins in farm silages under Northern European conditions in Finland, 37 grass silage and 6 whole-crop cereal silage batches were analysed separately for surface, core and, if present, visibly mouldy spots. Mycotoxins were found in 92% of the samples. All mouldy samples contained mycotoxins. Beauvericin was the most common mycotoxin in grass silages and roquefortine C in whole-crop cereal silages. In mouldy samples, beauvericin, mycophenolic acid and roquefortine C were the most common mycotoxins in the grass silage and mycophenolic acid in the whole-crop cereal silage. Aflatoxins were not found in any of the samples. On average, all samples contained more than one type of mycotoxin. Concentrations of mycotoxins varied considerably from very low to very high values. The results of this survey indicate that silage-fed ruminants can be exposed to a broad range of mycotoxins. The absence of visible moulds does not always indicate mycotoxin-free feed. All moulded samples contained mycotoxins and some at very high concentrations, and they contained more different types of mycotoxins than samples without visible mould. Thus, feeding mouldy feeds to animals should be avoided.

Development of safe storage guidelines for prairie-grown flaxseed

Safe storage guidelines are essential to ensure that harvested commodities maintain the highest levels of quality during the varying environmental conditions through storage. These guidelines serve as effective tools for farmers to schedule appropriate post-harvest operations to prevent quality and quantity losses. The objective of this study was to develop safe storage guidelines for flax by investigating the effect of storage variables (storage temperature, moisture content, and storage period) on the seed deterioration parameters of flaxseed. The seed deterioration parameters include, germination, free fatty acid value (FAV), visible mould, protein content and moisture content (MC). To this end, flaxseeds were conditioned to 7, 8, 9, and 13% moisture content and stored at 10, 20, and 30 °C for a period of 16 weeks. Storage variables depicted statistically significant (P = 0.05) effect on the germination rate and FAV. Visible mould was apparent in the 4th and 3rd weeks for flaxseed with high moisture content (13%) stored at 20 and 30 °C. The protein content of flaxseed stored at different relative humidity conditions did not depict any statistically significant changes over the entire storage period but the significant changes were observed over the various temperature ranges. It was concluded that safe storage of flaxseed can be ensured at 10 and 20 °C for more than 16 weeks if the moisture contents are maintained at 7, 8, and 9%. Under rare scenarios, if the crop is to be stored at a high moisture content (∼13%) and at temperatures in excess of 20 °C, it must be dried to lower moisture levels to within 3 weeks of storage. When storing flaxseed for an extended period of time, it is recommended to keep the temperature below 20 °C to ensure high quality and to maintain seed viability.

Determination of Nutritional Quality and Aerobic Stability of Sorghum, Maize, and Sorghum-Maize Mixture Silages

The current study aimed to determine the nutritional quality and aerobic stability of sorghum, maize, and their mixture silages without any additives. Sorghum and maize were harvested at dough stage from a local farm in Tekirdağ. Fresh plant materials were chopped to a length of 2-3 cm and packed into polythene bags, and vacuumed. A total of 12 vacuum-packed silos (4 replications in each treatment) were prepared with sorghum (S), maize (M), and a mixture of sorghum-maize (SM) forage (w:w, 50:50 according to dry matter) and stored at room temperature for 60 days. The chemical and microbiological composition of silages with the rate of aerobic deterioration upon aerobic exposure were evaluated. Based on the pH and ammonia nitrogen concentration, all silages could be classified as good quality. The water-soluble carbohydrate level of the SM group increased due to mixing S and M forages, leading to improved lactic acid content. The NDF and ADF values of silages varied between 520.52-588.32 and 234.98-309.01 g kg-1, and the differences between silages were significant (P<0.01). The Hemicellulose/Cellulose ratio of S, M, and SM silages were found 0.94, 1.49, and 1.18, respectively. The lactobacilli and yeast content of silages were significant and varied between 5.18-7.41 and 5.18-7.29 log cfu g-1, and the highest and lowest values were observed in SM and S silages, respectively (P<0.01). No visible mold was detected in all silages after 5 days of aerobic exposure (P>0.05). The pH, CO2, and yeast numbers were varied in groups between 4.88-6.74, 55.71-119.33 g kg-1, and 8.40-9.01 log cfu g-1. It was concluded that it is possible to improve the nutritional and fermentation characteristics of sorghum and maize silage by ensiling their mixture. However, it is highly recommended that silage additives should be used to guarantee and strengthen the fermentation and aerobic stability of silage mostly made by a mixture of these two energetic forage crops.

Prevalence of Asthma and Its Associating Environmental Factors among 6-12-Year-Old Schoolchildren in a Metropolitan Environment-A Cross-Sectional, Questionnaire-Based Study.

We aimed to evaluate the prevalence of asthma and its associating environmental factors within a 6–12-year-old population. A cross-sectional, questionnaire-based study was conducted in primary schools located in the capital of Hungary; 3836 eligible parent-reported questionnaires were evaluated. Besides the International Study of Asthma and Allergies in Childhood (ISAAC) phase three core questions for asthma, the survey also assessed various potential risk factors. We introduced the umbrella term cumulative asthma as the union of physician-diagnosed asthma and current wheezing to estimate the lifetime prevalence of asthma. Current wheezing and physician-diagnosed asthma showed a frequency of 9.5% and 6.3%, respectively. They contributed to a cumulative asthma prevalence of 12.6% among the sampled population, with a girl-boy percentage of 37.4% to 62.6%. Air-pollution and weedy areas were associated with greater risk for asthma, while a suburban residence showed lesser odds. Indoor smoking, visible mold, and keeping a dog were defined as risk factors for asthma, while the presence of plants in the bedroom and pet rodents were associated with lower odds ratios. The consumption of fast food, beverages containing additives and margarine were significantly higher in asthmatics, while we found frequent sport activity and cereal intake associated with lower odds ratios for asthma. In this urban environment, we identified an increased asthma prevalence compared to some previously published studies, but the cross-sectional design and the different methodology did not permit us to draw timeframe-dependent conclusions.

Sensory quality and shelf-life of locally produced British butters compared to large-scale, industrially produced butters

PurposeThe purpose of this pilot-scale study was to compare the quality of traditionally manufactured butters from local, small British producers with the quality of butters that are produced industrially.Design/methodology/approachButter samples were obtained after supervised site inspections of three traditional-butter manufacturers and one large-scale butter producer. The samples were subject to initial microbiological, chemical and sensory testing, followed by a refrigerated shelf-life study over 24 weeks.FindingsTraditional butters matched or exceeded the sensory quality of industrial butters, but spoilage microorganisms tended to grow faster on traditional butters. This seemed to be related to poorer water droplet dispersion in the manufacture of some of the traditionally made butters. Visible mould appeared on two of the traditional butters after eight weeks, but this occurred well after the nominal “best before” date.Originality/valueProlonged lockdowns due to the current coronavirus disease (COVID-19) pandemic pose a threat to the food supply chain, and food produced by local manufacturers may become increasingly important. However, are foods produced by local small-scale manufacturers of a quality comparable to that produced using large-scale production facilities? To the best of the authors' knowledge, there is no comparative study of the quality and shelf-life of traditionally-produced and industrially-produced butters. The current work presents such a comparison together with an outline of how the process of traditional butter-making differs from commercial production in Britain.

Modelling mould growth in domestic environments using relative humidity and temperature

Damp and high levels of relative humidity (RH), typically above 70–80%, are known to provide mould-favourable conditions. Exposure to indoor mould contamination has been associated with an increased risk of developing and/or exacerbating a range of allergic and non-allergic diseases. The VTT model is a mathematical model of indoor mould growth that was developed based on surface readings of RH and temperature on wood in a controlled laboratory chamber. The model provides a mould index based on the environmental readings. We test the generalisability of this laboratory-based model to less-controlled domestic environments across different values of model parameters. Mould indices were generated using objective measurements of RH and temperature in the air, taken from sensors in a domestic setting every 3–5 min over 1 year in the living room and bedroom across 219 homes. Mould indices were assessed against self-reports from occupants regarding the presence of visible mould growth and mouldy odour in the home. Logistic regression provided evidence for relationships between mould indices and occupant responses. Mould indices were most successful at predicting occupant responses when the model parameters encouraged higher vulnerability to mould growth compared with the original VTT model. A lower critical RH level, above which mould grows, a higher sensitivity, and larger increases in the mould index all consistently increased performance. Using moment-to-moment time-series data for temperature and RH, the model and its developments could help inform smart monitoring or control of RH, for example to counter risks associated with reduced ventilation in energy efficient homes.

Household determinants of biocontaminant exposures in Canadian homes

Exposure to biocontaminants, such as dust mites, animal dander, bacteria, and mold, is associated with a range of health effects. This study identified household characteristics associated with indoor biocontaminant loadings in four Canadian cities. Floor dust was collected in 290 Canadian homes in Edmonton, Halifax, Montreal, and Windsor. The dust samples were analyzed for house dust mite allergens (Der f 1 and Der p 1), cat allergen (Fel d 1), cockroach allergen (Bla g 1), beta‐(1,3)‐D‐glucan, and endotoxin. Household information was obtained through questionnaires and home inspections. We performed univariate and multivariate analyses to identify household determinants of biocontaminant loadings and mold odor presence. We observed large regional variations for all biocontaminants, except for cockroach allergen. The ranges of the contaminants measured in loadings and concentrations were similar to that of previous Canadian studies. Household characteristics including presence of carpeting, low floor cleaning frequency, older home age, presence of pets, and indoor relative humidity above 45% were positively associated with the presence of multiple indoor biocontaminants. High floor cleaning frequency and use of dehumidifiers were negatively associated with the presence of multiple indoor biocontaminants. Mold odor was positively associated with older home age, past water damage, and visible mold growth.

Analytical study on Fungal Cellulase Produced by Penicillium Expansum grown on Malus Domestica (Apple Fruits)

The rise in world industrialization and the cost of importing enzyme by local industries have led to arise in the search for novel and native enzyme producing microorganisms. Cellulase is an enzyme that catalyzes the breaking down of carbon chains in cellulose and hemicellulose, this research therefore aimed at studying fungal cellulase produced by Penicillium expansum grown on malus domestica (apple fruits). Fresh apple fruit was allowed to deteriorate under laboratory condition until there was visible mould growth. The mould with desired features of the organism of interest was subcultured by direct plating on PDA plates to which 10 % streptomycin has been added to prevent bacterial contaminants. The plates were incubated at 28±2 0C for 7 days until a visible mass of blue mycelia appear. The isolate was further subcultured onto freshly prepared media until pure culture was obtained. Characterization and identification of isolate were done using macroscopy and microscopy techniques. The isolate was re-inoculated into healthy apple fruits and the fruits were incubated at temperature of 28±2 oC for 8 days. Cellulolytic activity was examined every day throughout the incubation period. Crude enzyme was extracted each day using standard methods. Carboxyl methyl cellulose was used as standard for the crude cellulase activity assay after extraction from the infected apple fruits using Dinitrosalicylic acid (DNSA). Culture parameters like pH and temperature were also optimized to determine their effect on cellulolytic activity of the fungus. Cellulase activity was defined as the amount of glucose produced in μmol/mg/min under the assay condition. The highest cellulase activity of 86.84±0.52 μmol/mg/min was observed on day 6 of incubation at 28±2 oC and at pH 7. In conclusion, it is evident from this research that P. expansum isolated could be used as potential novel organism for industrial production of cellulase under optimized fermentation conditions.

Contribution of Visible Surface Mold to Airborne Fungal Concentration as Assessed by Digital Image Quantification.

The rapid monitoring of total fungi, including air and surface fungal profiling, is an important issue. Here, we applied air and surface sampling, combined with digital image quantification of surface mold spots, to evaluate the contribution of surface fungi to airborne fungal concentrations. Cladosporium, Penicillium, Aspergillus, and yeast often appeared in the air or on wall surfaces during sampling. The indoor/outdoor concentration ratios (I/O ratios) demonstrated that the airborne concentrations of commonly found fungal genera outdoors were higher than those indoors (median I/O ratio = 0.65–0.91), excluding those of Penicillium and yeast. Additionally, the surface density (fungal concentration/area) of individual fungi showed no significant correlation with the airborne concentration, excluding that of Geotrichum. However, if a higher surface ratio (>0.00031) of mold spots appeared in the total area of an indoor environment, then the concentrations of Aspergillus and Geotrichum in the air increased significantly. Our results demonstrated that the airborne concentration of indoor fungi is significantly correlated with the outdoor concentration. A higher density of surface fungi does not necessarily contribute to a high fungal concentration in the air. In contrast to fungal density, quantification of the surface fungal area is recommended to assess the risk of surface fungi propelling into the air.

Maize as a nightmare: Food safety and toxicity in rural Kenya

This article discusses how Kenyan farmers engage with potentially toxigenic mould growing on the maize they produce, buy, process, consume and feed their animals. Aflatoxins, a group of mycotoxins produced by strains of Aspergillus flavus, can severely harm the livers of humans and animals, causing cancer, liver failure and death. Detection of the invisible, tasteless, and odourless toxins is only possible through expensive scientific testing, largely absent in rural Kenya. Yet local conceptions of aflatoxin focus on the visible mould in everyday food production and consumption practices. This includes constant inspection and separating mouldy kernels and grains during drying and storing to prevent the potentially present mould from spreading and to ensure food safety. This article investigates how practices like separating grains from maize kernels and inspecting the dried maize before grinding show how food is handled under constant, yet flawed, engagement with potential toxicity.

Cross-sectional associations of indoor environmental parameters and socioeconomic indicators with bedroom dampness schoolchildren-related exposures in Porto homes

Considering the time spent in enclosed environments, children are particularly vulnerable to indoor dampness-related indicators exposure. Seventy-six homes from 8 to 10 years old children were used to investigate the prevalence of home dampness-related indicators and their relationship with indoor environmental parameters and socioeconomic indicators, in Porto-Portugal. Few studies have included a walkthrough inspection and environmental parameters measurements in children's bedrooms. Results indicate that mean CO2 levels were significantly higher in bedrooms with visible mould growth (1093 vs. 757 ppm, p = 0.006) and in bedrooms with tendency for formation of condensations (978 vs. 752 ppm, p = 0.025). Mean relative humidity levels were also significantly higher in bedrooms with visible mould growth (61 vs. 53 %, p = 0.012). A positive correlation was found between the occupation density and the mould spot extent in the room (ρ = −0.658, p < 0.001). Recent buildings have tendency for having less water traces indoor; and parents with lower school levels (0–9 years) have higher tendency for having condensation on windows. This research makes a contribute to the literature on exposure to indoor pollutants.

Home dampness/mold(D/M) improvement in children's residences over the past decade in China-a comparison of repeated surveys in 2010 and 2019

There is mounting evidence that exposure to household dampness/mold (D/M) is the cause of respiratory, allergic diseases for children. While few research focuses on the effects caused by building environment changes, from a longitudinal investigation perspective, especially for China experiencing a rapid development in recent years. This study aimed to explore the changes of D/M in Chinese homes over the past 10 years and identify the impacts of climate, building energy efficiency and residents' behaviors. The cross-sectional surveys were repeatedly conducted in children’ residences in 2010 (Period I) and 2019 (Period II), among Taiyuan, Urumqi in northern China, and Nanjing, Shanghai, Wuhan, Changsha, Chongqing in southern China. Finally, 23465 children in Period I and 34720 children in Period II were involved, with no changes of residences since birth. The results showed that the proportions for reported D/M indicators were significantly reduced in Period II: e.g., 93.8% and 84.1% residents respectively answered no visible mold spots and damp stains in current residences, compared to only 78.3% and 62.2% in Period I. Southern homes accounted for high proportions for D/M indicator occurrences; warm-humid climate, annual higher precipitation and lower sunshine hours, etc., exacerbated the indoor D/M exposure risks. While residents' behaviors like ventilation, airing quilt/beddings, regular cleaning ameliorated the reported D/M significantly. The findings, from a temporal and spacious dimension perspective, advance our understanding of indoor D/M changes, precisely improvement in children’ homes over the past 10 years, benefiting to promote indoor air quality standards in China.

Sleep deprivation in two Saskatchewan First Nation communities: a public health consideration

ObjectivesSleep deprivation is a common problem in Canada and is associated with many health problems. More than a quarter of Canadians get fewer than the recommended sleep hours (<7 h). This paper examines the prevalence and risk factors for sleep deprivation in two First Nation communities in Saskatchewan, Canada. MethodsThe baseline cross-sectional survey was completed between 2018 and 2019 in collaboration with the two Cree First Nation communities in Saskatchewan, Canada. There were five hundred and eighty-eight participants participated in the survey from two communities. A Multivariate logistic regression model was used for analysis. ResultsThe prevalence of sleep deprivation (<7 h of sleep) was 25.4%. The multivariate logistics regression revealed that middle and older age groups, visible mold in the house, and being male with nighttime insomnia symptoms were significantly associated with a higher risk of sleep deprivation among study participants in the study. ConclusionsIn these two First Nation communities, a higher proportion of the participants reported having sleep deprivation. This was a unique study, which evolved from ongoing research collaboration with two First Nation communities in Saskatchewan, Canada. Findings will be helpful in the management of patients with sleep deprivation in these communities; as well as for co-creating policy with the communities and future research priorities.

Two Patients Colonised with Absidia Corymbifera in an Intensive Care Unit Likely Secondary to an Abnormally Plumbed Renal Dialysis Point

Background Two adult patients within our adult intensive care unit grew Absidia corymbifera from clinical samples 24 hours apart. Both patients were colonised with the organism although one patient with a serious underlying condition did receive antifungal therapy. Due to the serious nature of Mucormycosis an infection control investigation was undertaken to identify and address any underlying sources with the aim of preventing further cases. Methods Visual inspection of the patient's environment was undertaken for investigation of water ingress or visible mould. Other investigations included air sampling and sampling of bed linen and shared equipment between patients. Results On review of one of the patient bedrooms an area of recent water ingress was identified. This was a plumbed in dialysis point which on further exploration had an abnormal plumbing collection to a sluice. As a result, there had been reflux of bed pan pulp into the wall space. Air sampling was negative. Swabs of linen were also negative and an ultrasound machine which was the only shared piece of equipment was also excluded. There was no construction work in the vicinity and checks on the patient's room ventilation parameters were satisfactory Conclusions It is likely the source of Absidia corymbifera was water ingress from an abnormally plumbed dialysis point in one of the patient bedrooms. Damp bed pan pulp supports the growth of fungi and if not removed within 72 hours will support fungal proliferation. Mould accumulating in a wall due to a slow water leak is thought to have played a role in cases of Mucor in the published literature. Fungal spores are released in bursts and travel far and wide which would explain colonisation in another patient in the unit at the same time. Following removal of the pulp and remedial plumbing no further cases were noted.

Snoring and environmental exposure: results from the Swedish GA2LEN study

ObjectiveHabitual snoring is associated with fatigue, headaches and low work performance. This cross-sectional study aimed to investigate if snoring is affected by environmental factors such as home dampness and exposure...

Early age exposure to moisture and mould is related to FeNO at the age of 6years.

Exposure to indoor moisture damage and visible mold has been found to be associated with asthma and respiratory symptoms in several questionnaire-based studies by self-report. We aimed to define the prospective association between the early life exposure to residential moisture damage or mold and fractional exhaled nitric oxide (FeNO) and lung function parameters as objective markers for airway inflammation and asthma in 6-year-old children. Home inspections were performed in children's homes when infants were on average 5months old. At age 6years, data on FeNO (n=322) as well as lung function (n=216) measurements were collected. Logistic regression and generalized additive models were used for statistical analyses. Early age major moisture damage and moisture damage or mold in the child's main living areas were significantly associated with increased FeNO levels (>75th percentile) at the age of 6years (adjusted odds ratios, 95% confidence intervals, aOR (95% CI): 3.10 (1.35-7.07) and 3.16 (1.43-6.98), respectively. Effects were more pronounced in those who did not change residential address throughout the study period. For lung function, major structural damage within the whole home was associated with reduced FEV1 and FVC, but not with FEV1/FVC. No association with lung function was observed with early moisture damage or mold in the child's main living areas. These results underline the importance of prevention and remediation efforts of moisture and mold-damaged buildings in order to avoid harmful effects within the vulnerable phase of the infants and children's immunologic development.

Household mold exposure interacts with inflammation-related genetic variants on childhood asthma: a case\u2013control study

BackgroundA number of studies have examined the association between mold exposure and childhood asthma. However, the conclusions were inconsistent, which might be partly attributable to the lack of consideration of gene function, especially the key genes affecting the pathogenesis of childhood asthma. Research on the interactions between genes and mold exposure on childhood asthma is still very limited. We therefore examined whether there is an interaction between inflammation-related genes and mold exposure on childhood asthma.MethodsA case–control study with 645 asthmatic children and 910 non-asthmatic children aged 3–12 years old was conducted. Eight single nucleotide polymorphisms (SNPs) in inflammation-related genes were genotyped using MassARRAY assay. Mold exposure was defined as self-reported visible mold on the walls. Associations between visible mold exposure, SNPs and childhood asthma were evaluated using logistic regression models. In addition, crossover analyses were used to estimate the gene-environment interactions on childhood asthma on an additive scale.ResultsAfter excluding children without information on visible mold exposure or SNPs, 608 asthmatic and 839 non-asthmatic children were included in the analyses. Visible mold exposure was reported in 151 asthmatic (24.8%) and 119 non-asthmatic children (14.2%) (aOR 2.19, 95% CI 1.62–2.97). The rs7216389 SNP in gasdermin B gene (GSDMB) increased the risk of childhood asthma with each C to T substitution in a dose-dependent pattern (additive model, aOR 1.32, 95% CI 1.11–1.57). Children carrying the rs7216389 T allele and exposed to visible mold dramatically increased the risk of childhood asthma (aOR 3.21; 95% CI 1.77–5.99). The attributable proportion due to the interaction (AP: 0.47, 95% CI 0.03–0.90) and the relative excess risk due to the interaction (RERI: 1.49, 95% CI 0–2.99) were statistically significant.ConclusionsIn the present study, there was a significant additive interaction between visible mold exposure and rs7216389 SNP on childhood asthma. Future studies need to consider the gene-environment interactions when exploring the risk factors of childhood asthma.

Evaluation of lactose oxidase as enzymatic antifungal control for Penicillium spoilage in yogurt

In this study, we investigated the antifungal activity of lactose oxidase (LO) as a potential biopreservative in dairy products. Our study objectives were to screen antifungal activity of LO against common mold strains, to detect the minimum inhibitory level of LO against the same strains, and to understand how LO affects the pH and lactic acid bacteria (LAB) counts in set yogurt. Five mold strains (Penicillium chrysogenum, Penicillium citrinum,Penicillium commune,Penicillium decumbens,and Penicillium roqueforti) were used throughout study. These strains were previously isolated from dairy manufacturing plants. Throughout the study, yogurts were stored at 21 ± 2°C for 14 d. Antifungal activity of LO was screened using 2 enzyme levels (1.2 and 12 g/L LO) against selected strains on the surface of a miniature laboratory set-yogurt model. For all tested strains, no visible mold growth was detected on the surface of yogurts covered with LO compared with control yogurt without LO. The minimum inhibitory level of LO against each strain was further investigated using 4 enzyme levels (0.12, 0.48, 0.84, and 1.2 g/L LO) on the miniature laboratory set-yogurt model. We detected 0.84 g/L LO as the minimum level inhibiting visible hyphal growth across strains. The minimum inhibitory level of LO varied for each individual strain. To study the effect of LO on the pH of yogurt, miniature laboratory set-yogurt models were covered with different enzyme levels (0.12, 0.48, 0.84, 1.2, and 12 g/L LO). At d 14, a difference was detected comparing pH values of treatments to control with no LO. Commercial low-fat set yogurt was used to study the effect of LO on LAB survival when yogurt surface was covered with 0.84 g/L LO under the same experimental conditions. Control with no LO was included. At d 14, 3 levels of catalase were added (0, 0.01, and 0.1%) to each treatment. To enumerate LAB, homogenized samples were plated on de Man, Rogosa, and Sharpe agar and incubated. Yogurts with 0.84 g/L LO had lower LAB counts compared with control yogurts, and catalase level did not have a significant effect on LAB counts. Our results demonstrated potential antifungal efficacy of LO against common spoilage organisms in dairy products with residual lactose and relatively low pH. Manufacturers should establish efficacy of LO against mold strains of interest and determine the effects of LO on organoleptic properties and LAB survival in set yogurt.

The monitoring of wall moisture in a property retrofitted with Internal Wall Insulation

The purpose of this study was to measure the long-term moisture build-up in the walls of a house which had been retrofitted with Internal Wall Insulation. This was done by embedding moisture sensors in the walls and then monitoring values over an eight-year period. The results showed that the wall moisture of embedded wood piece sensors had increased to a value of 18–20 % over 8 years. In a comparable wall, which had been treated with water repellent brick cream, the build-up of moisture was significantly reduced to 9–10 % over the same period. This wall was examined after the 8-year period and no visible mould was evident.

Field Ecology and Food Suitability of Tarsonemus spp. (Acari: Tarsonemidae).

Tarsonemus bakeri Ewing (Acari: Tarsonemidae) is a species of mite commonly associated with citrus in many countries including the United States. A short report in 1942 suggested this species is phytophagous, but it has not been reported as a pest in citrus or any other crop since then. A single survey of 78 orchards in three growing regions in California demonstrated that Tarsonemus spp. mites were only associated with leaf samples that had visible sooty mold. A seasonal population study in one citrus orchard showed that all life stages of Tarsonemus spp. were present year-round on leaves and fruit, with the population on fruit reaching a peak in December (59.7 ± 15.2 mites per fruit). Results from a food suitability study showed that the population declined sharply on both plastic and leaf substrate when the mites were not provided a supplementary food source. When supplementary food was provided in the form of Alternaria, honeydew, molasses, or combinations of these, mites survived and multiplied throughout the 29-d study, irrespective of the substrate. Tarsonemus bakeri were found on excised, decaying leaves collected from an orchard. These studies verify that Tarsonemus spp. are associated only with sooty mold in citrus orchards. T. bakeri populations cannot sustain themselves on leaf tissue alone, indicating that they are nondamaging to citrus and therefore need not be considered a phytosanitary concern by importing countries.