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B De Schutter

Publications and source records attributed to B De Schutter.

4 recordsLinked to original sources
PubMed2002

The influence of fungicides on the growth of Trichoderma asperellum.

Numbers of strains of Trichoderma asperellum are known as biological control agents of certain root pathogens of tomato (Lycopersicon esculentum). The restricted use of fungicides is sometimes useful in combination with these biological control agents. Therefore some experiments were conducted to evaluate the growth of T. asperellum in the presence of fungicides as Previcur (active substance propamocarb) and Sumico (with the active substance carbendazim and diethofencarb). The influence of these fungicides was first examined in laboratory conditions. The fungus was brought on a potato dextrose agar where the fungicides Previcur, Sumico and carbendazim were added in a concentration of 0.1x, 1x and 10x the recommended dose. The growth of T. asperellum was totally inhibited by the three Sumico and carbendazim concentrations. T. asperellum knew a small but significant decrease of growth when the 10x dose of Previcur was added. Afterwards the influence of these fungicides on the fungus was tested in field conditions in the greenhouse. The fungus was applied to the roots of the tomato plant, which was grown on a rockwool medium. Previcur and Sumico were submitted to the plants using the normal procedure. The results of the tests showed that in field conditions there was no effect of the fungicide treatment on the presence of the fungus, although the laboratory tests showed the opposite for Sumico. To explain this contradiction two other experiments were conducted to follow the migration of the Sumico after treatment. A residue analysis showed that the highest concentration of Sumico was detected in the rockwool medium, and some residues were found in the drain water and the stems. Even with a 100x recommended dose of Sumico the fungus was still present the day after the treatment.

Benzimidazoles↗
PubMed2002

Suppression of Pythium spp. by Trichoderma spp. during germination of tomato seeds in soilless growing media.

In the Flemish horticulture Pythium spp. is an important pathogen of tomato plants (Lycopersicon esculenthum) in soilless growing media. Therefore some experiments were conducted to evaluate the possibility of decreasing the damage caused by Pythium spp. by Trichoderma spp. In a tray with several growing media, a suspension of Trichoderma conidia (10(6)/ml growing medium) was applied two weeks before sowing. On some objects, a compost extract (Biostimulus) was added. The growing media used in the experiment were rockwool, recycled rockwool and recycled coconut fibre. After sowing, the trays were covered with perlite. Three isolates of Trichoderma spp.: T. asperellum (Biofungus), T. harzianum (Tri 003) and Trichoderma sp. (KHK) and two isolates of Pythium spp.: P. ultimum (MUCL) en P. aphanidermatum (HRI, UK) were used. Propamocarb was used as a chemical standard. The use of coconut fibre growing medium resulted in a higher percentage (36%) of germination than the rockwool media when only Pythium spp. was used. The presence of the spontaneous developing microflora in the coconut fibre medium gave probably also a suppression of Pythium spp. For that reason the results of the suppression by Trichoderma spp. are not easy to explain and very variable on the different objects. Pythium ultimum was more suppressed than P. aphanidermatum on all the growing media and the application of all the Trichoderma isolates increased the germination percentage of tomato seeds. T. asperellum (Biofungus) gave on rockwool also a good result for the suppression of P. aphanidermatum (increasing of germination with 48%). This effect was comparable with the propamocarb treatment (48%). T. harzianum (Tri 003) gave a small suppression (22%) and Trichoderma sp. (KHK) gave almost no suppression of P. aphanidermatum (7%). When less Trichoderma conidia were applied the germination percentage decreased. The adding of a compost extract (Biostimulus) had no influence on the results. This experiment shows that application of Trichoderma conidia in the presence of Pythium spp. increases the germination percentage of tomato seeds, sowed in the used soilless growing media.

Belgium↗
PubMed2001

Colonisation of soilless growing media for tomato by Trichoderma harzianum.

An experiment was conducted to evaluate the distribution of T. harzianum in soilless media used in greenhouse growing systems for tomatoes. Growing media based on rockwool and based on coconut fibre were included. The fungus was applied to the roots of the plant by means of a conidial suspension. The upper plant parts were removed from the coconut fibre an the rockwool slab after 10 and 15 weeks respectively. Both the coconut fibre and the rockwool slab were divided into fragments with a width of 10 cm. The coconut fibre medium fragments were again divided in an upper and a lower part. For every fragment the CFU/g was determined by two different methods. In the first method a known volume of growing medium was brought into suspension using a blender and diluted. Appropriate dilutions were plated on a selective medium. In the second method a known volume of growing medium was spread directly upon a selective medium in petri dishes. All dishes were incubated at room temperature and colonies were counted. Results showed that in the case of the coconut fibre growing medium T. harzianum was isolated in every fragment of the substrate. Highest densities were measured at the site of inoculation. In the lower part of the fragments less CFU/g were counted than in the upper part. In the case of the rockwool growing medium, there were several fragments in which no T. harzianum was isolated. The dilution technique demonstrated to be most useful in cases of high density. The direct spreading-method is best applied when low densities are expected. These observations demonstrate that the growing medium based upon coconut fibre is more appropriate for colonisation by T. harzianum. However, densities are higher at the site of inoculation in both tested growing media.

Biomass↗