Czech Mycology 51(2-3): 157–170             Article published: 25th May, 1999 doi: 10.33585/cmy.51203

GHERBAWY Y. A. M. H., ABDELZAHER H. M. A.

Isolation of fungi from tomato rhizosphere and evaluation of the effect of some fungicides and biological agents on the production of cellulase enzymes by Nectria haematococca and Pythium ultimum var. ultimum.

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Abstract

Forty-five species and two species varieties belonging to twenty-six genera of fungi were isolated from 30 soil samples from the rhizosphere of tomato plants.The fungi most frequently isolated were Aspergillus jlavus, A.fumigatus, A. niger, A. terreus, Gibberella fujikuroi, Nectria haematococca and Rhizopus stolonifer. Ridomil and Vitavax-captan (10, 50 and 100ppm) had no significant effects on the activity of Cl and C enzymes of Nectria haematococca. C enzyme activity was slightly increased at 10 and 50ppm, but slightly decreased at 100ppm. Vitavax-captan (10, 50 and 100ppm) significantly decreased Cl enzyme activities of N. haematococca. C enzyme activity was slightly increased at 10 and 50ppm, but at 100 ppm it showed a slightly inhibitory effect. Ridomil caused a slight increase in the activity of C and Cl enzymes by Pythium ultimum var. ultimum at low and moderate doses but the highest dose of Ridomil caused a slight reduction. Vitavax-captan slightly increased the activity of C and Cl enzymes in P. ultimum var. ultimum. Normal and sterilised filtrates of Myrothecium verrucaria, Penicillium oxalicum and Trichoderma harzianum induceda small decrease in Cl enzyme activity of Nectria haematococca. The sterilised filtrates of the three fungi tested caused greater inhibition compared to the normal filtrate.The production of C enzyme was slightly increased with normal and sterilised filtrates of Penicillium oxalicum and Trichoderma harzianum, but was significantly increased by both types of filtrates of Myrothecium verrucaria. The two types of filtrate of all fungi tested did not significantly affect the activity of Cl and C enzymes by lithium ultimum var. ultimum. Production of extracellular protein by Nectria haematococca was not significantly affected by any dose of the tested fungi cides. It was slightly increased by the two types of filtrate of the three tested fungi but significantly increased by the normal filtrate of Myrothecium verrucaria. The normal filtrate of all the fungi tested enhanced extracellular protein production to a greater extent than the sterilised filtrate. Extracellular proteins of Pythium ultimum var. ultimum were slightly increased by all doses of Vitavax-captan and low doses only of Ridomil, also two types of filtrate of all tested fungi caused a slightly increasing effect.


Keywords:     Biologicalcontrol, root-rot, fungicides Nectria haematococca, Pythium ultimum var. ultimum

Full citation:

Gherbawy Y. A. M. H., Abdelzaher H. M. A. (1999): Isolation of fungi from tomato rhizosphere and evaluation of the effect of some fungicides and biological agents on the production of cellulase enzymes by Nectria haematococca and Pythium ultimum var. ultimum. – Czech Mycology 51(2-3): 157–170. copy to clipboard


doi: 10.33585/cmy.51203

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