Tag Archives: Bacillus stearothermophilus

273-280 H. Lõiveke
Incidence of Fusarium spp. on several field crops in Estonia and their toxicity towards Bacillus stearothermophilus
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Incidence of Fusarium spp. on several field crops in Estonia and their toxicity towards Bacillus stearothermophilus

H. Lõiveke

Estonian Research Institute of Agriculture, Teaduse 13, EE75501 Saku, Harjumaa, Estonia;e-mail: heino.loiveke@eria.ee

Abstract:

The article provides an overview of the occurrence of Fusarium spp. on grain produced in Estonia from 1973–2004, the occurrence of Fusarium spp. in the common root rot complex of cereals in 1977–1985 and potato tubers with dry rot symptoms in the yield of 1996–2000. The dominating species on grain were (contaminated samples, %) F. avenaceum (Fr.) Sacc. – 28.0–30.3; F. poae (Pk.) Wr. – 7.4–9.5 F. semitectum Berk. et Rav. – 7.0–9.0; F. oxysporum (Schlecht) Snyd. et Hans. – 7.4-8.0; accompanied by F. ventricosum App. et Wr., F. sporotrichioides Sherb. var. minus Wr., F. verticillioides (Sacc.) Nirenberg, F. culmorum (W. G. Sm.) Sacc. and F. sambucinum Fuck. In the common root rot complex of barley, F. culmorum – 16.8; F. sambucinum – 2.5; F. avenaceum – 2.2; F. oxysporum – 1.7; and F. poae – 1.3 (contaminated samples, %) dominated. In potato with dry rot, F. culmorum – 26.7; F. solani (Mart.) Sacc. – 20.0; F. poae – 15.0; F. oxysporum – 13.3 and F. sulphureum Schlecht – 8.3 (contaminated tubers, %) dominated. The occurrence of toxic isolates both on grain and potato was established. Of Fusarium isolates recovered from grain (total 287) 5.6% were highly toxic, and 88.1% mildly or medium toxic to Bacillus stearothermophilus. Of 15 isolates found on potato, 1 was highly toxic and 9 were mildly to medium toxic. Fusarium spp. has been presented according to Gerlach & Nirenberg (1982).

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195–205 H. Lõiveke, E. Ilumäe and H. Laitamm
Microfungi in grain and grain feeds and their potential toxicity
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Microfungi in grain and grain feeds and their potential toxicity

H. Lõiveke¹, E. Ilumäe¹ and H. Laitamm²

¹Estonian Research Institute of Agriculture, Teaduse 13, Saku, 75501, Harjumaa, Estonia;
e-mail: heino.loiveke@mail.ee; ene.ilumae@mail.ee
²Agricultural Research Centre, Teaduse 4/6, Saku, 75501, Harjumaa, Estonia;
e-mail: helgi.laitamm@pmk.agri.ee

Abstract:

The aim of the research work was to study microfungi in grain (spring and winter wheat) and grain feeds of domestic origin and determine their composition with special attention on toxigenic and allergenic species.
The total number of fungi was estimated on wort agar or on the nutrient substratum of Czapek. The species and number of Fusarium were defined on the selective medium of Nash & Snyder. For a mycological survey of grain samples, the moist chamber method was used in the year of 1992. The fungi were determined by microscopy, using corresponding nominators (Raper et al., 1949; Raper et al., 1965; Arx, 1970; Bilai et al., 1988). The classification of Fusarium has been made according to Gerlach & Nirenberg (1982). The toxicity of isolated fungi was defined by means of a test organism, Bacillus stearothermophilus (Watson & Lindsay, 1982). Spring wheat of the years 1992, 1993, 1994 and winter wheat of the years 1992, 2002 and 2003, and spoilt grain feeds of the years 1997–2002 were investigated.
About half of the identified 63 fungi species are either potentially toxigenic or allergenic. In 1992–1994; on average Alternaria spp. occurred on 72% of spring wheat seeds and on 45% of winter wheat seeds, Cladosporium spp. on 20% and 8% of the seeds, Aspergillus spp. on 6% and 9% of the seeds, Verticillium spp. on 13% and 23% of the seeds, Fusarium spp. on 23% and 64% of the seeds, respectively. Penicillium spp. was represented very differently: in 1992 and 1994 on 10%, in 1993 on 80–90% of the seeds. The species known as toxicants were also from the genera Chaetomium, Cochliobolus, Gliocladium, Mortierella, Mucor, Rhizopus, Stachybotrys, and Trichothecium. In spoilt grain feeds the potential toxicants were represented from the genera Acremonium, Alternaria, Aspergillus, Cladosporium, Fusarium, Penicillium, Rhizopus, andTrichothecium. Allergenic species were represented by the genera Epicoccum, Penicillium, Aspergillus, and Ulocladium. The toxicity of fungi isolated from grain, on the basis of the growth inhibition zone of B. stearothermophilus, was 0–7 mm, whereas on fungi isolated from spoilt feeds it was 0–18 mm. The most toxic fungi werePenicillium cyclopium, Penicillium sp., Trichothecium roseum, Aspergillus terreus, Paecilomyces varioti, Rhizopus nigricans, and Acremonium sp.

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185–196 H. Lõiveke, H. Laitamm and R.-J. Sarand
Fusarium fungi as potential toxicants on cereals and grain feed grown in Estonia during 1973–2001
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Fusarium fungi as potential toxicants on cereals and grain feed grown in Estonia during 1973–2001

H. Lõiveke¹, H. Laitamm² and R.-J. Sarand²

¹Estonian Research Institute of Agriculture, Teaduse 4, Saku, 75501 Harjumaa, Estonia; e–mail: heino.loiveke@mail.ee
²Estonian Control Centre of Plant Production, Teaduse 4/6, Saku, 75501 Harjumaa, Estonia; e-mail: riho.sarand@tmkk.ee

Abstract:

This study was carried out to investigate the occurrence of the genus Fusarium Link ex Fr. on cereal grain grown in Estonia and grain feeds made of the named cereal grain. Within the period of 1973–1981, occurrence of genus Fusarium was identified in 1,065 grain seed samples, and, within 1997–2001, in 29 samples of grain feed.Fusarium sp. was identified in 67–100% of the studied wheat samples, and, depending on the year, infection was detected in 13–67% of the seeds. In the case of rye,Fusarium species were identified in 38–86% of the studied samples and infection was found in 8–23% of the seeds, with barley the figures were 45–97% and 14–46%; and oats 55–100% and 15–65%, respectively.
The study indicated that the infection spread more intensively when corn was lodged, as a result of rainy autumn and late harvest. 16 species and 4 varieties of Fusariumwere found on seeds. According to the survey (in 707 samples), the most common species were the following: F. avenaceum (Fr.) Sacc., F. poae (Pk.) Wr., F. oxysporum(Schlecht) Snyd. et Hans., F. ventricosum App. et Wr., F. sporotrichioides Sherb. var. minus Wr., F. verticillioides (Sacc.) Nirenberg and F. culmorum (W.G.Sm) Sacc. Mycotoxin producing species F. avenaceum, F. poae, F. sporotrichioides, F. oxysporum, F. verticilliodes, F. sambucinum Fuck., F. equiseti (Corda) Sacc. and F. culmorumwere detected in 50–60% of the studied samples.   As a result of the studies on domestic grain feed (29 samples) carried out within 1997–2001, Fusarium spp. was found in 51.7% of the samples, whereas Fusarium toxins were detected in seven samples out of nine. 31.3% of Fusarium isolates were highly toxic, and 37.5% were toxic on Bacillus stearothermophilus. One isolate of F. verticillioides, one of F. culmorum, F. tricinctum (Corda) Sacc. and two of F. sp. proved to be highly toxic.

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