Detection and Quantification of Airborne Conidia of Fusarium circinatum, the Causal Agent of Pine Pitch Canker, from Two California Sites by Using a Real-Time PCR Approach Combined with a Simple Spore Trapping Method

Pinus radiata (Monterey pine), a tree native to coastal California and Mexico, is widely planted worldwide for timber production. A major threat to Monterey pine plantations is the fungal disease pine pitch canker, caused by Fusarium circinatum (Hypocreales). We present a novel trapping approach using filter paper in combination with a rapid molecular method to detect the presence of inoculum in the air. The assay is also useful for diagnosing the presence of the pathogen on plants. The test is based on the F. circinatum specific primer pair CIRC1A-CIRC4A, which amplifies a 360-bp DNA fragment in the intergenic spacer region of the nuclear ribosomal operon. Real-time PCR was used to calculate the number of fungal spores present in each reaction mixture by comparing the threshold cycle (Ct) of unknown spore samples to the Ct values of standards with known amounts of F. circinatum spores. The filter paper method allows prolonged and more sensitive spore sampling in the field compared to traditional traps using petri dishes filled with selective medium. A field test at two sites in coastal California infested with pine pitch canker was carried out during the summer and fall of 2002. Spore counts were in the range of ca. 1 × 10³ to ca. 7 × 10⁵/m², with the highest spore counts in the fall, suggesting a seasonal fluctuation.     

The role of olfactory stimuli in the location of weakened hosts by twig‐infesting Pityophthorus spp.

1. Senescing, shade‐suppressed, or broken branches of Monterey pine Pinus radiata are infested by twig beetles in the genus Pityophthorus (Coleoptera: Scolytidae). The studies reported here tested whether twig beetles can discriminate between healthy and pitch canker‐diseased branches, whether diseased branch tips produce more ethylene than undamaged controls, and whether ethylene and other volatiles, produced by the plant in response to tissue damage, are utilised by twig beetles in host location. 2. Significantly greater numbers of twig beetles were reared from pitch canker‐symptomatic than from pitch canker‐asymptomatic branches of Monterey pine collected in the field. 3. Needles of Monterey pine branches inoculated with the pitch canker fungal pathogen Fusarium circinatum produced significantly higher levels of ethylene than needles of control branches, and this was evident just prior to, and during, symptom expression. 4. In trapping studies in which pheromone production was prevented, there was no evidence of attraction of twig beetles to a source of ethylene alone, to cut host branches, or to cut branches treated with the ethylene‐releasing compound, ethephon. The results suggest that twig beetles identify weakened branches after landing.     

A genetically homogenous population of Fusarium circinatum causes pitch canker of Pinus radiata in the Basque Country, Spain

Pitch canker, caused by Fusarium circinatum, is a destructive disease of Pinus species and has recently been shown to represent a substantial threat to natural and commercial forests in northern Spain. The genetic diversity of F. circinatum in the Basque Country of Spain was assessed by characterising 96 isolates based on vegetative compatibility groups (VCGs), mating type assays, polymorphic DNA-markers and amplified fragment length polymorphism (AFLP) analyses. For this purpose, F. circinatum isolates were collected from diseased Pinus radiata as well as from insects associated with this host. Overall, a low level of diversity was detected in the population. The isolates represented only two VCGs and they were all of the same mating type. AFLP analyses revealed three genotypes and polymorphic DNA-markers specific for F.?circinatum showed nine genotypes. The most common genotypes represented 97% of all isolates for AFLP analysis and 68% of isolates for the polymorphic DNA-marker sets. Over all, this indicates that pitch canker in the Basque Country of Spain is caused by a clonally propagating population of F. circinatum, typical of a recently introduced pathogen.     

Monterey Bay Phytoplankton. II. Resting Spore Cycles in Coastal Diatom Populations

The purpose of this study is to examine the role of "restingspores" in natural population cycles of temperature, neriticdiatoms. Resting spores are a conspicuous element of centricdiatom populations in most neritic and some deep-water environmentsof the world oceans. Until recently the spores have been accepted,almost axiomatically, as surviving as a seasonal benthic stagewhich reinoculate the water column at the onset of favorablegrowth conditions. Data to support this hypothesis, however,is limited and contradictory. In my study, I am examining theoccurrence of resting spores in relation to vegetative cellcycles and oceanographic conditions in Monterey Bay, California,a nearshore upwelling-dominated system. I have utilized samplesfrom the water column, from settling-tubes, and from sedimentcores to document the cycles. Resting spore cycles were observed for many neritic species,and spore cycles for abundant species were considered in detail.Resting spore formation was associated with low nitrate concentrationsin surface waters. After spore formation in the water columnspores were found in settling-tubes and in sediment samples.Spore formation was a frequent event and spores were often presentin the water column and in the sediments. Observations of spore cycles in the present study were consistentwith the prevailing idea that resting spores function as benthicresting stages in coastal populations. The pelagic retentionand/or dispersal in coastal circulation cells, however, alsoappeared to be highly likely. The study has demonstrated thepotential for resting spores to function as survival stagesin Monterey Bay and in other regions with similar hydrographicconditions. The present evidence regarding the role of restingspores suggests that resting spores may have a wide range offunctions, and a more inclusive (or alternate) resting sporehypothesis is suggested.     

Sequence characterized amplified polymorphic markers for the pitch canker pathogen,Fusarium circinatum

Fusarium circinatum is the causal agent of pitch canker disease of pines. This pathogen is thought to have originated in Central America and currently poses a serious threat to commercial pine plantations in many areas of the world. In this study, polymorphic molecular markers were developed for F. circinatum using the internal short sequence repeats‐polymerase chain reaction (ISSR‐PCR) technique. Nine sequence characterized amplified polymorphic markers were developed. Thirty‐two putative alleles were observed among 103 F. circinatum isolates from different geographical areas using the nine polymorphic markers. These sequence characterized amplified polymorphic markers can be used as genetic tools in populations studies of F. circinatum.     

Fungal spores prevalent in the aerosol of the city of Caxias do Sul, Rio Grande do Sul, Brazil, over a 2-year period (2001–2002)

This study was carried out over a 2-year period (2001 and 2002) with the aim of identifying the fungal population in the aerosol of the Southern city of Caxias do Sul, RS, Brazil. Sampling was performed using Hirstȁ9s non-viable volumetric method. Our results show the presence of a large number of fungal spore types, a total of 41. Three groups were predominant: Deuteromycotina, Ascomycotina and Basidiomycotina. In 2001, Deuteromycotina taxa represented 44.61% of the total annual spore counts, with the largest concentration occurring in the fall (58,637 spores); in 2002, it represented 40.03% of the total annual spore counts, and the largest concentration was obtained in the summer (68,317 spores). Ascomycotina was present at the same level (24.5%) in both years of sampling, and the highest concentrations were found out in the summer (2001: 42,183 spores; 2002: 29,461 spores). Basidiomycotina represented 22.37% of the total annual spore counts in 2001, and 20.41% in 2002, with the largest concentrations found in the summer (2001: 35,988 spores; 2002: 30,212 spores). The most frequent fungi found during the study period were Cladosporium, Coprinus, Leptosphaeria, Aspergillus/Penicillium and Ganoderma. Permanent aerobiological monitoring would be necessary to detect associated environmental variations.     

Spore dispersal of a resupinate ectomycorrhizal fungus, Tomentella sublilacina, via soil food webs

Patterns of fungal spore dispersal affect gene flow, population structure and fungal community structure. Many Basidiomycota produce resupinate (crust-like) basidiocarps buried in the soil. Although spores are actively discharged, they often do not appear to be well positioned for aerial dispersal. We investigated the potential spore dispersal mechanisms of one exemplar of this growth form, Tomentella sublilacina. It is a widespread ectomycorrhizal fungus that sporulates in the soil organic horizon, can establish from the spore bank shortly after disturbance, but also can be a dominant species in mature forest stands. We investigated whether its spores could be dispersed via spore-based food webs. We examined external surfaces, gut contents and feces from arthropod fungivores (mites, springtails, millipedes, beetles, fly larvae) and arthropod and vertebrate predators (centipedes, salamanders) from on and around T. sublilacina sporocarps. Spore densities were high in the guts of many individuals from all fungivore groups. Centipede gut contents, centipede feces and salamander feces contained undigested invertebrate exoskeletons and many apparently intact spores. DAPI staining of spores from feces of fungivores indicated that 7-73% of spores contained intact nuclei, whereas spores from predators had lower percentages of intact nuclei. The spiny spores often were lodged on invertebrate exoskeletons. To test the viability of spores that had passed through invertebrate guts we used fecal droppings of the millipede Harpaphe haydeniana to successfully inoculate seedlings of Pinus muricata (Bishop pine). These results indicate the potential for T. sublilacina spore dispersal via invertebrates and their predators in soil food webs and might help to explain the widespread distribution of this species. It is likely that this is a general mechanism of dispersal for fungi producing resupinate sporocarps, indicating a need to develop a fuller understanding of the linkages of soil food webs and spore dispersal.     

GENETIC VARIABILITY WITHIN A POPULATION AND BETWEEN DIPLOID/HAPLOID TISSUE OF MACROCYSTIS PYRIFERA (PHAEOPHYCEAE)1

Multi-locus DNA fingerprints using an M13 probe were obtained for eight individuals of giant kelp Macrocystis pyrifera (L.) C. Ag. collected from Monterey Bay, California. For each individual, DNA was extracted from a diploid blade and from ca. 10⁹ haploid spores that were released from four to Jive sporophylls. Viable or swimming spores from one individual were pooled and referred to as a spore group. A total of 34 bands (4–19 kb) was detected in DNA fingerprints from the eight blades and eight spore groups, with individual blade or spore groups exhibiting 7–18 bands (mean = 12.6). One band (4.5 kb) was present in all 16 samples. Eight bands were detected in 11–14 of the 16 samples. Similarity indices were calculated for all pairwise comparisons of fingerprint bands among all possible combinations of blades and spore groups. Mean similarity indices for the eight blades (0.51, SE = 0.032) and spore groups (0.56, SE = 0.031) were significantly lower than for the eight comparisons of the blade and spore groups from a single individual (0.86, SE = 0.052). The data indicate that DNA fingerprints can be used to measure genetic variation within populations of M. pyrifera because variation of DNA fingerprints associated with meiotic products (spores) of a given individual is small relative to variation observed among individuals within the population. Additionally, fingerprint variation between diploid vegetative tissue and haploid meiotic products may be a measure of genetic change due to recombination or DNA turnover mechanisms.     

Performance of the Coriolis air sampler,a high-volume aerosol-collection system for quantification of airborne spores and pollen grains

The Coriolis δ air sampler manufactured by Bertin Technologies (France) is a continuous air sampler, dedicated to outdoor monitoring of airborne spores and pollen grains. This high-volume sampler is based on patented Coriolis technology delivering a liquid sample. The air is drawn into a conical vial in a whirling type motion using suction; particles are pulled against the wall by centrifugal force. Airborne particles are separated from the air and collected in a liquid medium. This innovative solution allows rapid analysis by several techniques including PCR assay and serological assay in order to measure the antigenicity/allergenicity of pollen grains and fungal spores. Also, traditional counting of pollen grains or taxa identification by optical microscopy can be done. A study has been carried out by the Health Protection Agency (HPA), Porton Down, UK, to measure the physical efficiency of the Coriolis air sampler. The physical efficiency of the sampler for collection of micro-organism-laden particles of various sizes has been compared with that of membrane filter samplers using the techniques described by ISO 14698-1. The Coriolis was operated simultaneously with membrane filter samplers in a controlled room where they were challenged with uniform-sized particles of different diameters containing bacterial spores. For the larger particle sizes, it was found that the physical efficiency of the Coriolis was 92% for 10-μm particles. The biological performance of the Coriolis in the collection of airborne fungal spores and pollen grains was evaluated in comparison with a Hirst spore trap (one-week tape-on-drum type sampler) which is one of the most frequently used traps in the measurement of outdoor pollen grain concentrations. The advantages and limitations of both technologies are discussed. The Coriolis was operated simultaneously with a Hirst spore trap in the sampling station of Réseau National de Surveillance Aérobiologique, France (RNSA); the pollen grain and fungal spore counts were analysed by optical microscopy. The pollen grain count m⁻³ collected was compared for both devices. The dispersion values were obtained and statistical analysis was carried out. This study shows that the Coriolis air sampler provided equivalent recovery of pollen grain and fungal spores compared with the volumetric trap standard method (not significantly different, W test, α = 0.05). Nowadays, the French-led project, acronym MONALISA, with financial support from the European Commission––Life-Environment (LIFE05 ENV/F/000068), is testing this innovative air sampler in order to measure the antigenicity/allergenicity of the main aeroallergen particles, i.e. Betula (birch), Poaceae (grasses), Parietaria (pellitory), Olea spp (olive tree), and Artemisia (mugwort) pollen grains, and Alternaria (fungal spores) to validate a new approach of monitoring instead of quantifying pollen grains by their morphology. The robustness and efficiency of the MONALISA system is being demonstrated at a national level throughout Europe in eight different countries with different bio-climatic and topography characteristics: France, UK, Finland, Poland, Spain, Portugal, Switzerland, and Italy.     

Quantitative association of bark beetles with pitch canker fungus and effects of verbenone on their semiochemical communication in Monterey pine forests in Northern Spain

The association between 11 species of bark beetles (Coleoptera: Scolytinae) and one weevil (Coleoptera: Entiminae) with the pitch canker fungus, Fusarium circinatum Nirenberg and O'Donnell, was determined by crushing beetles on selective medium and histone H3 gene sequencing. Pityophthorus pubescens (Marsham) (25.00%), Hylurgops palliatus (Gyllenhal) (11.96%), Ips sexdentatus (B?rner) (8.57%), Hypothenemus eruditus Westwood (7.89%), Hylastes attenuatus Erichson (7.40%), and Orthotomicus erosus (Wollaston) (2.73%) were found to carry the inoculum. In addition, the root weevil Brachyderes incanus L. (14.28%) had the second highest frequency of occurrence of the fungus. The responses of the insects to a range of verbenone doses were tested in field bioassays using funnel traps. Catches of P. pubescens, a species colonizing branch tips of live trees, were significantly reduced in a log-linear dose-dependent relationship. Catches of I. sexdentatus, an opportunistic species normally attacking fresh dead host material, were also gradually reduced with increasing verbenone dose. Catches of Tomicus piniperda L., O. erosus, Dryocoetes autographus (Ratzeburg), H. eruditus, Xyleborus dryographus (Ratzeburg), Hylastes ater (Paykull), Hylurgus ligniperda (F.), H. attenuatus, and B. incanus were not significantly affected by verbenone. The effects of verbenone were consistent with differences in host-age preference. Semiochemical disruption by verbenone in P. pubescens and I. sexdentatus could represent an integrated pest management strategy for the prevention of the spread of pitch canker disease between different stands. However, several species associated with F. circinatum were unaffected by verbenone, not supporting this compound for prevention of the establishment of potential vectors in Northern Spain.     

Adaptive Potential of Maritime Pine (Pinus pinaster) Populations to the Emerging Pitch Canker Pathogen,Fusarium circinatum

There is a concern on how emerging pests and diseases will affect the distribution range and adaptability of their host species, especially due to different conditions derived from climate change and growing globalization. Fusarium circinatum, which causes pitch canker disease in Pinus species, is an exotic pathogen of recent introduction in Spain that threatens its maritime pine (P. pinaster) stands. To predict the impact this disease will have on the species, we examine host resistance traits and their genetic architecture. Resistance phenotyping was done in a clonal provenance/progeny trial, using three-year-old cuttings artificially inoculated with the pathogen and maintained under controlled environmental conditions. A total number of 670 ramets were assessed, distributed in 10 populations, with a total of 47 families, 2 to 5 half-sibs per family, and 3–7 ramets per clone. High genetic variation was found at the three hierarchical levels studied: population, family and clone, being both additive and non-additive effects important. Narrow-sense and broad-sense heritability estimates were relatively high, with respective values of 0.43–0.58 and 0.51–0.8, depending on the resistance traits measured (lesion length, lesion length rate, time to wilting, and survival). These values suggest the species'' high capacity of evolutionary response to the F. circinatum pathogen. A population originated in Northern Spain was the most resistant, while another from Morocco was the most susceptible. The total number of plants that did not show lesion development or presented a small lesion (length<30 mm) was 224 out of 670, indicating a high proportion of resistant trees in the offspring within the analyzed populations. We found large differences among populations and considerable genetic variation within populations, which should allow, through natural or artificial selection, the successful adaptation of maritime pine to pitch canker disease.     

Sources of Variability in the Measurement of Fungal Spore Yields

Variability in the production of fungal spores and in the measurement of spore yields was investigated in four species of fungi: Colletotrichum gloeosporioides, Colletotrichum coccodes, Colletotrichum phomoides, and Acremonium strictum. When the fungi were grown on solid medium in microplates and spore yields were measured by counting the subsamples with a hemacytometer, the variability among hemacytometer squares was always the largest source of variation, accounting for 51 to 91% of the total variation. Variability among replicate cultures and results of repeat experiments were generally also significant. The effect of square-to-square variability on the precision of spore yield measurement was minimized by counting a moderate number (ca. 30) of squares per culture. Culture-to-culture variability limited the practical precision of spore production measurements to a 95% confidence interval of approximately the mean ± 25%. We provide guidelines for determining the number of replicate cultures required to attain this or other degrees of precision. Particle counter-derived spore counts and counts based on spore weights were much less variable than were hemacytometer counts, but they did not improve spore production estimates very much because of culture-to-culture variability. Results obtained by both of these methods differed from those obtained with a hemacytometer; particle counter measurements required a correction for spore pairs, while the relationship between spore weights and spore counts changed as the cultures aged.     

Study of airborne fungal spores in Madrid, Spain

The concentration of fungal spores in the atmosphere of Madrid was recorded and analyzed for the year 2003. Airborne spores were sampled continuously with a Hirst-type spore trap located on the roof of a building of the School of Pharmacy, at about 8 m above ground level. Correlation between the mean daily spore concentrations and meteorological variables were explored by means of Spearman’s correlation analyses. Seventy spore types were identified, of which the most numerous were Cladosporium, Aspergillaceae (conidia), Coprinus, Agaricales (basidiospores), Ustilago (teliospores) and Pleospora (ascospores). These six types of spores represented more than 70% of the total. Cladosporium represented 41% of the total fungal spores, while Ustilago spores, the concentrations of which in May and June exceeded 47% of the monthly total spore count, constituted the second most important group. Spores reached their highest concentrations in the spring months, and in the autumn, mainly in October. A␣positive significant correlation was found between airborne spore counts and temperature and relative humidity. The results provide a picture of the spectrum of airborne fungal spores present in the atmosphere of Madrid and of the `peak' periods of their presence. Future studies will provide more detailed information on the seasonal dynamics of the spores most frequently found in the air as well as on the extent to which atmospheric conditions influence their release, dispersion and sedimentation processes.     

Anthropogenic fire and bark thickness in coastal and island pine populations from Alta and Baja California

Aim  Native American fire use influenced bark thickness of coastal and island Monterey pine ( Pinus radiata D. Don) and bishop pine ( Pinus muricata D. Don) populations.
Methods  Basal bark thickness and d.b.h. were measured in two common-garden pine plantations that included all five native Monterey pine populations and nine of 10 native bishop pine populations. One-factor analysis of covariance was used to determine if significant differences in bark thickness existed between island and coastal populations.
Results  Bark thickness was measured on 228 Monterey and 42 bishop pines. Bark thickness in coastal and island Monterey pine populations was significantly different. Bark thickness in coastal and island bishop pine populations was not significantly different.
Main conclusions  Basal bark was thick in populations where there was a history of Native American burning. Basal bark was thin in two island populations where Native Americans have been absent or distant from the pine populations. While other influences no doubt affect the evolution of lower-bole bark thickness, it appears that frequent anthropogenic fires may be a powerful selection force.     

Diagnostics in allergic diseases by correlating pollen/fungal spore counts with patient scores of symptoms

Pollen/fungal spore counts have been performed since 1977 in Copenhagen and since 1979 in Copenhagen, Viborg, Nykobing Falster and Nykobing Mors. Four Burkard Seven Day Recording Volumetric Spore Traps were used. Fungal spore counts were performed in the same period using a BIAP Slit Sampler (placed in the Copenhagen area). The study was carried out by the Danish Asthma-Allergy Association's interdisciplinary Aerobiology Group. In 1979 at the Allergy Clinic, Copenhagen County Hospital at Lyngby, data from the pollen/fungal spore counts were compared with daily scores of 95 patients' symptoms and medicine-index. Seventy-eight patients were scored in the entire period where symptoms occurred. For diagnostic purposes of allergy to pollen and fungal spores, previous patient history and symptom scores correlated to the pollen/fungal spore counts showed similarity and to some extent supplementary corrections to the diagnosis based on previous patient history, skin tests, laboratory tests, and provocation tests.     

Genetic dissection of fusiform rust and pitch canker disease traits in loblolly pine

Loblolly pine (Pinus taeda L.) exhibits genetic resistance to fusiform rust disease (incited by the biotrophic fungus, Cronartium quercuum f. sp. fusiforme) and pitch canker disease (incited by the necrotrophic fungus, Fusarium circinatum). In this study, a total of 14,015 loblolly pine cuttings from 1,065 clones were screened in controlled greenhouse conditions to identify phenotypes of clones, families, and parents that guide a genetic dissection of disease traits associated with pitch canker and fusiform rust. A total of 23,373 phenotypic data points were collected for lesion length (pitch canker) and gall score, gall length, and gall width (fusiform rust). We verified heritable fusiform rust and pitch canker traits and calculated parental, clonal, and full-sib family rankings for both diseases. Genetic correlations revealed that traits associated with fusiform rust are genetically distinct from one another, and that the genetic mechanisms underlying pitch canker and fusiform rust resistance are independent. The disease phenotyping described here is a critical step towards identifying specific loci and alleles associated with fusiform rust and pitch canker resistance.     

In vitro formation of resting spores by the insect pathogenic fungus Entomophaga maimaiga

Field-collected resting spores (azygospores) of the fungal pathogen of Lymantria dispar (gypsy moth), Entomophaga maimaiga, have been used to release this biological control agent in areas where this pathogen is not established. We have found that E. maimaiga can produce resting spores in vitro using Grace's insect tissue culture medium (95%) plus fetal bovine serum (5%). The majority of spores become mature between 7 and 21 days after cultures are initiated. Spore production varies by fungal isolate; of 38 isolates tested, 10 produced no resting spores while 7 produced >1000 resting spores/ml. Resting spore production was not affected when isolates were mixed. Glycerol (used for fungal storage), trehalose, and selected amino acids each inhibited resting spore formation. Fetal bovine serum was required for spore production but the presence of >5% yielded lower resting spore densities. A large surface area:volume ratio (12.5 cm(2):ml versus 4.2 cm(2):ml) was required for abundant formation of resting spores. At present, resting spores have only been produced in small volumes with a maximum of 3 x 10(4) resting spores/ml.     

Determination of airborne fungal spores of Gaziantep (SE Turkey)

The aim of this study was to present the first airborne fungal spore research results of SE of Turkey. The presence and abundance of fungal spores were investigated with a Hirst-type volumetric spore trap (Lanzoni, VPSS 2000) for 2 years between the periods January 2010 and December 2011. A total of 211,521 spores and 47 fungal taxa belonging to Anamorphic Fungi, Phyla Ascomycota and Basidiomycota were recorded. Aspergillus/Penicillium spores type, unidentified spores, spores of Myxomycota and hyphal fragments were also recorded as groups. The relationship between fungal spore counts and several meteorological parameters was examined. Cladosporium was determined as the predominant genus (56.48 %); hyphal fragments (14.94 %), Ustilago (13.96 %) and Alternaria (5.79 %) were revealed as the common fungal aerosols of Gaziantep atmosphere. With this study, the first aeromycological survey of SE of Turkey has been conducted and new information on the field of aerobiology in Turkey has been introduced.     

Effects of weather conditions on selected airborne fungal spores in the southern part of the state of Enugu,Nigeria

A study of airborne fungal spore was carried out at nine locations in the southern part of the state of Enugu, Nigeria, from March 2005 to February 2006. The aim of the study was to ascertain the variations in selected fungal spore types at the sites owing to weather conditions. The variation in airborne fungal spores of 14 taxa was studied using modified Tauber pollen traps including Alternaria, Corynespora, Curvularia, Drechslera type, Endophragmiella, Botryodiplodia, Ganoderma, Gliomastrix, Nigrospora, Pithomyces, Spegazzinia, Sporidesmium, Tetraploa and Ustilago. The frequency of the spore types recorded showed considerable variation. The highest spore counts were recorded in July, June and October. The highest numbers of fungal spores were recorded during the rainy season (June–October) to early dry season (November–December). The peak of occurrence of most selected fungal spore types was July. The highest percentages of fungal spores were documented at the recording stations Mgbowo Junction, UNTH Ituku Ozalla and Oji River Express Junction. Spearman’s correlation analyses were performed for the monthly amounts of the fungal spore types and monthly meteorological factors. The numbers of Curvularia, Nigrospora and Sporidesmium was significantly correlated with relative humidity, while those of Endophragmiella, Pithomyces and Nigrospora were significantly correlated with temperature. A significant correlation was also found between the number of Nigrospora spores and light intensity and Sporidesmium spores and wind velocity. Relative humidity and temperature seem to be the most important weather conditions affecting the frequency of the selected spore types in the atmosphere.     

Airborne fungal spores in a sawmill environment in Palakkad District, Kerala, India

Concentration of airborne fungal spores inindoor and outdoor environments of a sawmill in Palakkad district of Kerala, India was studied with Burkard Personal Slide Sampler from January to December 1997. Total spore concentration in the indoor and outdoor showed a 3:2 ratio. Higher spore count was observed in indoor in January and in outdoor in October. Thirty three fungal spore types were identified from the indoor and twenty six from the outdoor. Aspergillus/Penicillium, Cladosporium, Nigrospora, Ganoderma, `other basidiospores' and ascospores were the dominant components of the airspora. Aspergillus/Penicillium, the most dominant spore type in the indoor contributed 51.19% and Cladosporium, the most dominant spore type in the outdoor contributed 44.75% of the total spores. The study revealed high prevalence of predominantly allergenic fungal spores in the sawmill environment.