Bestrijding bacterievuur bloei infecties met biologische controle organismen (BCO’s) toegepast via hommels bij appel en peer: deel 2

    Project Details


    Main research question/goal

    Fire blight - Erwinia amylovora (Ea) - poses a real threat to pear orchards and sensitive apple varieties, not only for the damage that can cause infestation in the orchards but also for the possibility of export to fire blight-free areas.
    In the past antibiotics such as streptomycin and oxytetracycline were used to control the bacterium during flowering, their use in fruit production has been banned in Belgium since 2005. The use of BCO's against fire blight during flowering is an addition to the classical known control strategies. 
    The flower, more specifically the pistil and the flower base (nectar glands), is a specific niche for microorganisms, but is also where Ea penetrates and infects the tree. Together with met PCF, KUL en UGent we aimed to develop a method for the protection of apple and pear flowers against fire blight infection by flower applications of biological control organisms (BCO's). When using bumblebees as a vector one could deliver BCO's on the pistil and the flower base over an entire flowering period and in this way realize a continuous input of BCO's in the orchard. 

    Research approach

    At the time of the project only two commercial BCO-products, Blossom Protect and Serenade ASO, were registered in Belgium for use against flower infections. We also looked for new candidate-BCO’s in the flower microbiome of local apple and pear cultivars. 
    The commercially available BCO's and new strains isolated in this project from the flowers of apple and pear, were compared on their potential for flower protection by artificial flower infections of Conference pot trees in the greenhouse. 
    Furthermore, we investigated whether the selected BCOs had any adverse effects on the bumblebees, and how efficiently the bumblebees spread the BCOs to the flowers in controlled greenhouse experiments. Two application strategies were tested: entomovectoring of the BCO and secondary spread by the bumblebees after BCO spraying. 


    Findings of the project with applications for apple and pear orchards were: (i) BCO Blossom ProtectTM was most effective in suppressing fire blight symptoms followed by Serenade® ASO, and combinations with newly isolated candidate BCOs did not add to their effect, (ii) BCO had to be sprayed more than once during flowering to be effective because the distribution of BCO by entomovectoring or secundary spread by bumblebees was not sufficient, and (iii) bumblebees can spread Ea in the orchard, hence, under weather conditions conducive for fire blight infections, it is recommended to remove the bumblebee nests from the orchard. 

    Effective start/end date1/10/1630/09/18