A. H. Moubasher

Studies on the fungus flora of three grains in Egypt.

In wheat, corn and sorghum grains twenty-six genera and seventy-seven species including sixteen ofAspergillus and twenty-one ofPenicillium were identified. In grain samples adjusted to various moisture levels (up to 18.8 % on a dry-weight basis) and stored for 4 months at 8†, 20† and 30† C seed-borne fungi were monthly identified and counted, and the germinability of the grains was tested. In the control samples (moisture content 7.1–8.2 %) temperature had no effect on the fungal counts and on the precentage germination. With the rise of temperature and moisture content the fungal counts markedly increased and the germinability declined. The list of fungi dominant in one or more of the experiments, included eight species ofAspergillus, six ofPenicillium, two ofFusarium and one each ofAlternaria andCurvularia. The order of dominance of these fungi varied according to the type of grain, the length of storage and the treatment.A. niger was the dominant organism in the control samples of the three grains. It could grow successfully at high moisture contents but above 15 %, it was usually overgrown by other fungi. In wheatP. citrinum andA. sydowii, in cornP. citrinum andA. terreus, and in sorghumA. terreus andA. niger were the dominant fungi at moisture contents above 15 % after four months storage at 30† C. When stored at 8† CPenicillium species tended to predominate over other fungi in grains with high moisture contents. In surface-sterilized grains adjusted to 15 % moisture content, inoculated with six dominant fungi separately and incubated at 30† C,A. niger, P. citrinum andP. variabile caused severe deterioration in the three grains;A. ochraceus in wheat only andF. moniliforme in wheat and corn;C. spicifer was slightly injurious to the three grains.

Studies on mycoflora of salt marshes in Egypt. i. sugar fungi

Thirty-four genera and 92 species, in addition to two varieties of Aspergillus nidulans, were isolated from 74 soil samples collected from different localities of salt marshes in Egypt. Aspergillus (17 species in addition to 2 varieties of A. nidulans) and Penicillium (17 species) were of high occurrence, from which A. niger, A. fumigatus, A. terreus and P. notatum were dominant. Five genera were of moderate occurrence and these were Cladosporium, Fusarium, Alternaria, Mucor and Rhizopus. Nine genera were of low occurrence, namely, Drechslera, ?Trimmatostroma, Paecilomyces, Stachybotrys, Cephalosporium, Humicola, Botryotrichum, ? Geolegnia and Scopulariopsis. Statistical analyses reveal that soil samples poor in total fungi were significantly higher in total soluble salts, Na and K content than samples with numerous fungi. The difference in organic matter content between poor and rich samples was non-significant.In newly reclaimed fields along the borders of salt marshes, Fusarium was the most numerous fungal genera from soil followed by Aspergillus whereas Cladosporium was completely absent.Comparison between the present results and those of the other studies showed that there is no fungal flora characteristic of salt marshes.

Toxigenic fungi isolated from Roquefort cheese.

To evaluate the potential for mycotoxin production by fungi contaminating blue-veined cheese, as well as by the ripening fungus,Penicillium roqueforti, the fungal flora of six of local and imported brands was determined. A total of 19 fungi were isolated from the six brands tested. Fourteen of the isolates were toxic to chicken embryos. The toxigenic fungi produced the following mycotoxins:Aspergillus fumigatus, kojic acid;A. versicolor, sterigmatocystin;Penicillium roqueforti, penicillic acid and unidentified toxic metabolites.

Keratinophilic fungi and other moulds associated with air-dust particles from Egypt

One-hundred and eleven species and three species varieties belonging to 39 genera were collected from 50 dust samples on the five media used at 28°C. Using the hair-baiting technique with horse hair, 10 species ofChrysosporium were isolated:C. asperatum, C. state ofArthroderma tuberculatum, C. indicum, C. inops, C. keratinophilum, C. merdarium, C. pannorum, C. queenslandicum, C. tropicum andC. xerophilum. True dermatophytes were isolated:Trichophyton verrucosum andTrichophyton sp. Also, numerous fungi tolerating high levels of cycloheximide were encountered, such as members ofAcremonium, Aspergillus andPenicillium.On plates of glucose or cellulose Czapek-Dox agar (free from sucrose) the most frequent fungi were:Alternaria alternata, Aspergillus flavus, A. flavus var.columnaris, A. fumigatus, A. niger, A. ochraceus, A. sydowii, A. terreus, Chaetomium globosum, Cladosporium herbarum, Emericella nidulans, Fusarium oxysporum, Mucor hiemalis, Penicillium chrysogenum, P. oxalicum, Scopulariopsis brevicaulis andUlocladium atrum.On plates of 50% sucrose or 10 and 20% NaCl-Czapeks agar, some interesting species were frequently encountered:Eurotium amstelodami, E. chevalieri, E. halophilicum, E. montevidensis, E. repens, E. rubrum andScopulariopsis halophilica. The isolated, fungi have been tested for osmophilicity and halophilicity, they showed different rates of growth on sucrose and sodium chloride-Czapeks medium of various osmotic potential.

Studies on air-borne fungi at Qena

Statistical analysis of the results revealed no relevant correlation between the wind velocity and the counts of air-borne fungal spores, estimated by the sedimentation plate method at two sites and levels 2 and 20 meters of sampling.

Selective effect of the systemic insecticide Phosphamidon on soil, root-surface and leaf-surface fungi

Results of the effect of Phosphamidon on soil, root- and leaf-surface fungi of Vigna sinensis var. azmerly were generally inconsistent. However, there were some consistent ones. Its effect on soil, root- and leaf-surface fungi persisted till after 40 days. In soil the total count was regularly increased after 20 days by the low and medium doses and after 40 days by the high dose. In the rhizosphere, Fusarium was almost consistently activated by the three doses after 5 days of treatment and by the low dose after 20 days. In the rhizoplane, the total count of fungi was lowered by the three doses after 40 days in the two sowings. Alternaria alternata was toxicated by the three doses after several experimental periods of the two sowings in the phyllosphere and phylloplane. When this insecticide was incorporated with the agar medium, it was of no significant effect on the total count of fungi at the low and medium doses but abnormally increased the total count at the high dose. In the liquid medium, the mycelia of the test fungi were not significantly affected except that of Penicillium corylophilum which was significantly retarded by the three doses and Rhizopus stolonifer which was significantly activated by the high dose.

Keratinophilic and other fungi isolated from combine harvester wheat and sorghum dusts and from the atmosphere of winnow sites in Egypt.

Three methods were used for the isolation of fungi in the present investigation: the dilution-plate method, hair-baiting technique with horse hairs and the “exposed plate” method. Sabourauds glucose agar at 28 °C was also used as isolation medium. 102 species and 2 species varieties belonging to 36 genera were collected from combine harvester wheat and sorghum dusts and from the atmosphere of hay or winnow sites.Chrysosporium was represented by 6 species:C. asperatum, C. indicum, C. keratinophilum, C. merdarium, C. pannorum andC. tropicum. Several filamentous fungi tolerating high levels of cycloheximide and other moulds were frequently encountered in the two types of dusts and in the two atmospheres, such as members ofAcremonium, Alternaria, Aspergillus, Cladosporium, Emericella, Eupenicillium, Fusarium, Paecilomyces, Penicillium, Piedraia, Rhizopus, Scopulariopsis and others.

Effect of benomyl on soil, root-surface and leaf-surface fungi

Summary Benomyl was almost regularly toxic to the total count of soil and root- and leaf-surface fungi, and the toxicity persisted till the end of the experiment. Most of the fungi were also toxicated at certain periods and doses. Altemaria alternata could noticeably resist the effect of Benomyl at most of the treatments and at some treatments its count was promoted. When incorporated with the agar medium, the counts of most of the soil fungi were drastically reduced by the three doses. Altemaria alternata could also survive the fungicide at the higher doses, while Rhizopus stolonifer was the only fungus whose count was significantly raised at the medium dose. In the liquid medium all test fungi were almost significantly retarded or completely eliminated by the three doses, except Cladosporium cladosporioides which was not significantly affected by any dose.

Effect of Treatment of Soil with Keratinaceous Material on Soil Fungi

In the early periods of soil storage, the total number of fungi almost regularly and significantly increased with the concentration of keratinaceous material (ground buffalo hooves) between 1% and 10%. A concentration of 20% was stimulative after 7 days and became toxic after 15 days and remained so through the end of the experiment. With increase in the storage period, the beneficial effect of all concentrations was lost and in the case of high concentrations (5–20%) toxic ammonia was produced.

Effect of dithane M-45 on cellulose-decomposing fungi in Egyptian soil

Abstract The fungicide Dithane M-45 when applied to the soil was regularly and significantly toxic to the total count of fungi at all doses used (4·48, 22·4 and 44·8 mg active ingredient per kg dry soil). The toxicity was regularly increased with dose and persisted till the end of the experiment (15 weeks). When Dithane M-45 was incorporated into the agar medium all test fungi were eliminated by the high dose (24·0 ppm). The low and medium doses were tolerated by some fungi. The decay of filter paper buried in the fungicide-treated soil was significantly reduced by the high dose after 1 and 3 weeks of incubation, while the decay of filter paper treated with this fungicide and buried in untreated soil was significantly retarded by the high dose only after all experimental periods of incubation (up to 15 weeks). The growth and sporulation of nine test fungi were eliminated by the three doses of Dithane M-45 except Chaetomium globosum, Fusarium moniliforme and Trichoderma viride which could grow restrictedly at the low dose only. Production of endo-1,4β- d -glucanase and mycelial dry weight were not significantly affected by the three doses in the case of Aspergillus niger, and by the low dose in the case of Alternaria alternata, Fusarium solani and Myrothecium verrucaria. In the case of other test fungi and other doses, endo-1,4β-glucanase production and mecelial dry weight were significantly inhibited.