With these in mind, our observations from today, 28 April 2017:
Today on my scouting, I was joined by Dr. Paul Hildebrand in the hunt for apothecia cups. It is like looking for a needle in a hay stack but we did find mature apothecia cups that are actively sporulating, so we have inoculum present at this time. |
| Can you find the apothecia cups? Like I said, a needle in a hay stack! |
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| Mature apothecia cups in moss under a highbush blueberry bush. |
Depending on variety and location, highbush blueberry development varied. I strongly encourage growers to check their fields and varieties for stage of growth to determine the need to spray. During our scouting today we did observe 'Bluecrop' with over 40% of the flower buds at F2, while late season variety 'Elliot' had less than 40% at the F2 stage.
Recommendations:A ‘fixed spray schedule’ may be used to manage the disease whereby the first fungicide spray should be applied when 40-50% of the flower buds have reached the F2 stage (flower bud scales separating). One or more additional sprays may be required on a 7-10 day schedule.
Alternatively, a ‘weather based spray schedule’ may be employed. This strategy uses temperature and leaf wetness duration to determine if an infection period has occurred. If an infection period occurs and mature apothecia are present, and flower buds have reached the 40-50% F2, then the grower has up to 72 hours after the start of the wet period to apply registered fungicides with back-action. These include Topas, Mission, and Funginex, although the latter cannot be applied if berries are to be exported to the US. Additional spray(s) may be required, depending on weather conditions, 7-10 days later.
Alternatively, a ‘weather based spray schedule’ may be employed. This strategy uses temperature and leaf wetness duration to determine if an infection period has occurred. If an infection period occurs and mature apothecia are present, and flower buds have reached the 40-50% F2, then the grower has up to 72 hours after the start of the wet period to apply registered fungicides with back-action. These include Topas, Mission, and Funginex, although the latter cannot be applied if berries are to be exported to the US. Additional spray(s) may be required, depending on weather conditions, 7-10 days later.
Finally, please remember that the observations and recommendations above are derived from data collected in Kings County, Nova Scotia and may not be applicable to your location. If you are to the south and/or west of Kings County you may well be ahead in development and if you are located to the east of the Valley you will generally be later. This forecast is to be used as a guide only for mummy berry disease management in Nova Scotia.
