Blueberry sclerotina berry drop survey and fungicide evaluation for control of wild blueberry diseases in New Brunswick
Bleuets NB Blueberries
Canada/New Brunswick Growing Forward 2 (Non-Business Risk Management Programs)
Enabling Agricultural Research and Innovation
To determine the presence, distribution and severity of sclerotinia berry drop in wild blueberry fields in New Brunswick. This will be conducted by surveying wild blueberry fields for the presence of S. sclerotiorum, collecting tissue samples from selected fields across NB and analysing the samples for the presence of the pathogen by plating the samples onto growth media in the laboratory.
To conduct replicated field trials to evaluate new fungicides for the control of foliar and berry diseases of the wild blueberry crop
The project will investigate the extent of sclerotinia berry drop in wild blueberry fields in NB. The project will also deliver multiple fungicide trials which can be used to support product registration within wild blueberries. The information from the disease survey and fungicide trials will be shared with other partners and to complement existing registration programs. Information gained through the survey and the field trials will be widely distributed to the NB blueberry Industry through field days, workshops, meetings fact sheets and project reports.
Sclerotinia berry drop survey: Results of the survey showed that no sclerotinia berry drop was found in the wild blueberry fields surveyed in 2016. No S. sclerotiorum was isolated from any of the samples collected during the first (early to mid-June) and the second (end of June) sampling periods. In 2015, of the fields surveyed (10 wild blueberry and 2 highbush blueberry fields), S. sclerotiorum was isolated from one wild blueberry field with an incidence of 2%. The low incidence during 2015 or absence in 2016 survey indicated that the presence of sclerotinia berry drop in New Brunswick fields is minimal or not present in most fields. This result could be associated with low S. sclerotiorum inoculum in most wild blueberry fields. Other fungal pathogens were also isolated from the wild blueberry plant tissue samples. The fungal pathogens isolated included Colletotrichum spp., Alternaria spp., Fusarium spp., Botrytis sp. and Pestalotiopsis sp.
Evaluation of fungicide for control of berry diseases (botrytis blight and monilinia blight) of wild blueberries in New Brunswick: In 2016, monilial blight pressure was moderate to high in most blueberry growing regions of New Brunswick. Thus, fungicide application was needed for monilinia blight management in all wild blueberry production regions. There was no significant difference among the treatments in monilinia blight incidence. However, treatments that received one or two applications of Bravo (during sprout year) and Tilt followed by Switch (crop year, Treatments 5 and 8) had relatively lower disease incidence compared to the untreated check (Treatment 1). Disease incidence was reduced by up to 8.7% compared to the untreated check. There was no difference among all treatments in total yield. The data collected measured the total harvest yield (all berries collected in the sampling area) and not the marketable yield. In commercial production, blueberries are screened at packing lines for any diseased berries. Berries with visible disease symptoms are collected and discarded. Thus, marketable yield of blueberry crop from untreated fields would be reduced as a result of removal of infected berries.