Efficacy evaluation of microencapsulated new strains of Trichoderma and Bacillus from Cornell University for controlling powdery mildew on greenhouse cucumbers

Project Code: BPI07-180

Project Lead

Gordon Genge - ICUS Canada

Objective

To evaluate formulations for seed and soil treatments of cucumbers for control of powdery mildew via resistance inducing colonizing biocontrol microorganisms, to persue registration for the products as a joint review registration between the Pest Management Regulatory Agency and the Environmental Protection Agency; and to demonstrate to and receive feedback from growers on the tested products and application protocols

Summary of Results

Background

Powdery mildew is one of the most damaging diseases of greenhouse cucumber. The disease is established in Canada and occurrence is widespread yearly with high pest pressure. There are few biological fungicides registered in Canada for control of this disease in greenhouse cucumbers. The lack of control products, as compared to those available to foreign competitors, affects the productivity and profitability of greenhouse cucumber production, constrains rotation of fungicide groups, and increases the risk of pathogen resistance to registered fungicides. Recent research demonstrates some biocontrol agent species are opportunistic plant symbionts with biocontrol inducing changes in plant physiology which can enhance resistance to pathogens. Biocontrol and growth enhancement is now possible through seed and soil applications, where microbes interact with roots (growth enhancement) and the whole plant (inducing systemic resistance), and finally, as a further protective measure through foliar sprays using the same organisms to control residual disease.

In this project, Trichoderma and Bacillus strains from Cornell University were formulated into prototype biocontrol products, which were tested in research (Guelph, Cornell) trials.

Approaches

Trials were conducted at Cornell University and Guelph University in 2008. The trials involved applying blends of a range of Trichoderma and Bacillus strains, formulated as a dry powder, to seeds or planting mix. Formulations were prepared at Cornell University and seeds and soils were treated with each individual formulation separately and in combination.

Treatments were compared with untreated controls: Plant growth (heights and fresh weights) were measured, and the incidence/severity of powdery mildew was assessed.

Results

Both Trichoderma strain F11Bab and B. subtilis strain TC1448, when applied either as a seed or a soil treatment, reduced the incidence and severity of powdery mildew between 15% and 70% on foliage. The degree of induced resistance depended on the cucumber variety, and the effect was less pronounced in more susceptible varieties. In addition, an increase in plant growth with certain strains of Trichoderma, including strain F11Bab, was observed.

Conclusions

Trials have demonstrated that the tested strains have potential to reduce powdery mildew in cucumbers and enhance crop growth. Further research is needed to identify the most promising strains that could lead to the development of a commercial product and a regulatory package for submission to Health Canada’s Pest Management Regulatory Agency.

 

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