West central Michigan small fruit regional report – July 5, 2016
Phomopsis canker is the most common disease at this time in blueberries. Sugar accumulation in ripening berries is at its peak. Growers should be alert to any symptoms of fruit rots, especially Anthracnose.
Michigan’s west central region is passing through a drought period with only 1.87 inches of rain for the past 25 days. This drought coincides with the period of fruit development in blueberries and summer raspberries. However, daily temperatures have remained below the 80s for the most part with an average daily minimum temperature of 52 degrees Fahrenheit and a daily maximum of 76 F. Those temperatures somehow are mitigating the impact of drought conditions, making it less extreme.
Currently, blueberries are in harvest with good quality fruit. Early varieties are producing a heavy crop and growers expect a large crop this season. There are some problems with low productivity in some fields that were affected by two years of winter damage. Those fields presented abundant flowers early in the season, but later presented a large “June drop,” and many canes were with fruit but only a few leaves. Some growers misidentified this condition as an effect of some chemical applied during bloom or after bloom. These effects are more visible in blueberry fields with nutritional deficiencies or located in sandy soils. Correcting these problems will take another year, but a good pruning and the correct nutritional program will help to mitigate the situation in the long term.
So far the presence of spotted wing Drosophila (SWD) in blueberry fields in the central region remains very low but is steadily increasing. Only in raspberries are we observing SWD actively reproducing, and more SWD females of the summer generation have been trapped there. We observed more males flying in blueberries than in other crops.