Articles
Assessing fungicide efficacy for improved management of the wild blueberry foliar disease complex in eastern Canada
Article number
1357_34
Pages
235 – 242
Language
English
Abstract
The wild blueberry foliar disease complex, comprised of blueberry leaf rust (Thekopsora minima), Sphaerulina leaf spot (Sphaerulina vaccinii) and Valdensia leaf spot (Valdensia heterodoxa), significantly reduces yield when left unmanaged in the vegetative year of production.
The once widely used chlorothalonil is no longer being used by many growers due to its deregistration.
Therefore, the objective of this study was to evaluate registered and future fungicide options for their impact on foliar diseases, leaf number and floral bud number.
Field trials conducted in Collingwood Corner and Londonderry (Nova Scotia) consisted of ten treatments: untreated, mefentrifluconazole, mefentrifluconazole + fluxapyroxad, mefentrifluconazole + pydiflumetofen, pydiflumetofen, pydiflumetofen + difenoconazole, prothioconazole, fluopyram + prothioconazole, prothioconazole + benzovindiflupyr, and prothioconazole + pydiflumetofen.
Disease pressure was significantly greater at the Londonderry location.
At both locations prothioconazole + benzovindiflupyr recorded up to 30% greater leaf number than the untreated, with prothioconazole + benzovindiflupyr and prothioconazole + pydiflumetofen resulting in up to 92% less disease incidence than the untreated.
At the Londonderry location, the untreated had 24% lower floral bud number than all fungicide treatments.
This study demonstrates that the current industry standard tank mix of prothioconazole + benzovindiflupyr offers the greatest control of foliar diseases.
Furthermore, this study has also shown that pydiflumetofen combined with prothioconazole could be considered part of the foliar disease management strategy once pydiflumetofen is registered for use on wild blueberries in Canada.
The once widely used chlorothalonil is no longer being used by many growers due to its deregistration.
Therefore, the objective of this study was to evaluate registered and future fungicide options for their impact on foliar diseases, leaf number and floral bud number.
Field trials conducted in Collingwood Corner and Londonderry (Nova Scotia) consisted of ten treatments: untreated, mefentrifluconazole, mefentrifluconazole + fluxapyroxad, mefentrifluconazole + pydiflumetofen, pydiflumetofen, pydiflumetofen + difenoconazole, prothioconazole, fluopyram + prothioconazole, prothioconazole + benzovindiflupyr, and prothioconazole + pydiflumetofen.
Disease pressure was significantly greater at the Londonderry location.
At both locations prothioconazole + benzovindiflupyr recorded up to 30% greater leaf number than the untreated, with prothioconazole + benzovindiflupyr and prothioconazole + pydiflumetofen resulting in up to 92% less disease incidence than the untreated.
At the Londonderry location, the untreated had 24% lower floral bud number than all fungicide treatments.
This study demonstrates that the current industry standard tank mix of prothioconazole + benzovindiflupyr offers the greatest control of foliar diseases.
Furthermore, this study has also shown that pydiflumetofen combined with prothioconazole could be considered part of the foliar disease management strategy once pydiflumetofen is registered for use on wild blueberries in Canada.
Publication
Authors
A.W. Cornel, D.C. Percival
Keywords
Vaccinium angustifolium, Thekopsora minima, Sphaerulina vaccinii and Valdensia heterodoxa, vegetative year
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