Research, SafeCrop Projects

FORMULA:

Researcher: Dietrich Stephan, Isabella Linda Bisutti

Partner(s) and place of activities: BBA, Darmstadt , SAFECROP, San Michele all’Adige

Scientific responsible of the project: Yigal Elad

SUMMARY or LIST of activities planned in 2006:

Formulation of Pseudomonas fluorescens and Trichoderma harzianum

Three main subjects were planed within FORMULA. From January to July 2006 most of the research activities were concentrated on activity 1.

1. Stabilization of sensitive Micro-organisms
Within activity 1 formulations for the desiccation sensitive micro-organism Pseudomonas fluorescens will be developed and tested in various plant/pathogen test systems.
A freeze drying process was developed for the two P. fluorescens isolates Pf 153 and CHA0. For the optimisation of the process different freezing and drying temperatures and different protectants were compared. The viability, storability and efficacy of freshly produced and freeze dried cells were investigated. After optimisation of the freeze drying process no significant reduction of viability and efficacy was measured before and after freeze drying.
In further experiments the production of P. fluorescens in different liquid media and temperatures was investigated. The results show that the biomass production of both isolates can be enhanced by optimising the nutrient composition.
Additionally, the influence of the fermentation on the quality of freeze dried cells of strain Pf 153 was investigated. Within these experiments fermentation time, three different liquid media and different heat and pH treatments at the end of the exponential phase of Pf 153 were compared. The results indicate that the fermentation time, but neither the media nor the heat and pH treatments, are influencing the viability and efficacy of Pf 153 after freeze drying.
Up to now, no realistic technology on the formulation of Pseudomonades is published. Therefore, these results are original and important for the utilization of Pseudomonades as biocontrol agents.
First samples of the experimental product of Pf 153 and CHA0 are send to SafeCrop in S’Michele to be tested for control of powdery mildew on strawberries. In addition to the existing bioassay model-system ‘detached leaves of Vicia faba / Botrytis cinerea‘, the experimental product will be tested in Darmstadt against powdery mildew on cucumber. As soon as the results of the experimental products are promising, the fermentation and formulation at technical scale (300 l) will be checked.
In a further step first experiments on the environmental stability (e.g. UV) of P. fluorescens will be set up.

2. Formulations for soil application
These activities were planed for 2006 focussing on the control of Armilaria mellea in strawberries with Trichoderma atroviride. First experiments were set up in 2005 but because of the long incubation time we stopped these activities when Johanna Covi left the project. These activities will be resumed as soon as we can standardize the production of T. atroviride in a solid state fermenter. Therefore, it will be rescheduled to 2007.

3. Optimisation of sprayable formulations
These activities will start in September 2006. It was planned to begin these activities in May 2006 as soon as the solid state fermenter (SSF) is available. The SSF is necessary for the experimental design of optimising sprayable formulations of Trichoderma harzianum. Up to now, the SSF is not available, but the company ProPhyta promised that the fermenter will be installed in Darmstadt at the end of August 2006. In addition to the experiments with the SSF different solid media and growth conditions will be compared at smaller scale. Right now, we are working out the experimental design so that these experiments can start at the end of September 2006.
The scientific impact of these activities is to develop formulations for the registered Trichoderma harzianum strain T 39 with lower residual effects and a more reliable efficacy in comparison to the Trichodex product.

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