Field validation of biocontrol strategies to control brown rot on stone fruit in several European countries.

Background: Brown rot caused by Monilinia spp. is the most significant disease of stone fruit. New approaches to fruit production have necessitated the development of control strategies that are more eco- and consumer-friendly. An efficient field strategy to control brown rot was previously designed based on the application of two biocontrol agents (BCAs), Bacillus amyloliquefaciens CPA-8 (CPA-8) or Penicillium frequentans 909 (Pf909), with calendar-based treatment. In the present study, the strategy was validated on different stone fruit hosts in four producing countries over two seasons.

Results: The results obtained were reported according to three different scenarios: Scenario 1, in which there was no presence of disease in the field; Scenario 2, in which high disease pressure occurred in the field and treatments (biologicals or chemicals) were not effective; and Scenario 3, with low or medium to high disease presence. The results were successful because, in general, BCA strategies were shown to control brown rot to a similar extent as chemicals strategies. We found that most of the trials conducted in this study were classed under Scenario 3 (62.5%), with only 12.5% and 25% of the trials classed under Scenarios 1 and 2, respectively.

Conclusion: These novel findings allowed the formulation of CPA-8 and Pf909 as valuable tools for farmers to produce stone fruits more competitively and meet consumer demand for safer and more environmentally friendly products. © 2021 Society of Chemical Industry.