Wild Blueberry Newsletter July 2023

Wild Blueberry Newsletter header graphic, text and a photo of blueberries and leaves

July 2023

Hello Everyone,

Fruit Ripening Update
This is certainly an interesting growing season. We have received plenty of rain after bloom which the wild blueberry plants welcome. In prune fields there is plenty of new growth which should lead to healthy bud set for next year’s crop. In crop fields, locations across the state remain at peak green fruit with blueberries ripening slowly from south to north (see table below).

Gap in Fruit Ripening
You are not going crazy if you see an early flush of blue fruit, then a gap in ripening, followed by a second flush of blue fruit. Thinking back to pollination in May, we had about 1 week of sunny but windy pollination, then 1-2 weeks of freeze events and poor pollination weather, and then finally a second flush of blossoms with good weather. This makes it challenging to decide when to begin harvest.

Fruit Flies
Fruit flies love moisture! The last few weeks have brought excellent weather conditions for fruit fly populations here in Maine. High humidity, scattered storms and warm conditions will likely lead to increasing captures. BMF (Blueberry Maggot Fly) and SWD (Spotted Wing Drosophila) traps are out and collecting flies. The Fanning lab monitors traps and found SWD in low numbers at every site (7 total) this week, which is a big increase from last week when a single female was found at one site. Sprays for BMF began this week in locations where thresholds were met. These sprays will also target SWD populations if present. Here are the Extension BMF (extension.umaine.edu/blueberries/factsheets/insects/201-monitoring-for-the-blueberry-maggot/) and SWD (extension.umaine.edu/blueberries/factsheets/insects/210-spotted-wing-drosophila/) monitoring and action threshold pages. One strategy to manage SWD is to begin harvesting early. Reach out to Phil Fanning at philip.fanning@maine.edu with any questions.

Phenology Report
Below is this week’s plant development update from crop fields. Visit the Phenology Tracker page of the website for weekly updates and images of each development stage.


Week 15 Crop Field Plant Development

Lily and Phil