Southeast Michigan fruit regional report – September 18, 2012

While spotted wing Drosophila continues to be very challenging in fall raspberries, this review of the season shows 2012 was difficult for most fruit production.


This certainly will be a season long remembered by fruit growers in east Michigan, as it has been the most weather and pest challenging season that almost all growers can remember. The combination of early record-breaking warmth in March and almost all of our tree fruit crops lost to freezes in late April, the extended drought and heat of this summer and, finally, the spotted wing Drosophila tsunami in fall red raspberries have been a struggle for fruit growers. I must have had well over 100 fruit growers share with me in the last few months that they can’t wait for the 2013 growing season, as they just want the season of 2012 to end.

The last straw for the string of freeze and frost events of this spring occurred on the morning of April 29. This event killed all of the remaining flowers and fruit for most of the tree fruit growers in east Michigan. The only exception to this freeze was for growers in the southern tier of Michigan counties and for a few growers in Romeo, Mich. Growers in these narrow regions had between 40 and 70 percent of a normal crop. Most Enviro-weather stations accumulated a record number of growing degree days this season.

Drought conditions continue to be a challenge for many fruit farms in east Michigan, with soil moisture supplies running much below normal. The areas affected by drought are not as widespread as was the case earlier this summer and the degree of wilting leaves is not as severe as it was a few weeks ago. Leaf yellowing and drop is common in most tree fruits in the last month. With the exception of fall red raspberries, most growers have stopped or are winding down irrigation for the year.

Our early warm season has been running about two weeks ahead of normal in terms of growth stages; this was the case for the entire season. We are more than three weeks ahead of normal in terms of growing degree day (GDD) totals, also for the entire season.

East Michigan Growing Degree Day Totals for March 1 to September 17





Commerce (Oakland)




Emmett (St Clair)




Flint (Genesee)




Lapeer (Lapeer)




Petersburg (Monroe)




Pigeon (Huron)




Romeo (Macomb)




Tree fruits

Apple harvest continues at the few farms that have a crop this season. Growers are harvesting Red Delicious and starting on Idared. Fuji are not ready yet, but are closer to being mature than most growers think they should be for this time of the season. Apple harvest is very slow this season because the crop is so early, light and spread out. There are many farms where apple quality is a problem, mostly due to freeze damage, resulting in many small, misshapen fruit. Grade out is approaching 40 percent at many farms. Fruit size has stalled at many farms due to drought stress.

Pests in apples this season with no apples have behaved much differently than in any other year that I have experienced. Most growers without a crop stopped all pest control operations after the major freeze events of late April. Codling moth has been the most notable insect that has not emerged as normal. We had a record-high trap catch from the first generation and then no trap catch for the second generation. We have also had some fruit infestation as well, even in blocks that had mating disruption.

With the drought and short crop, we had much less apple maggot trap catch this season. Mites were generally not a problem this season. San Jose scale fruit damage is continuing the trend of increased pressure over the last few years. In fact, it appears that we will have a third generation adult flight this long season.

Apple scab was a bit of a challenge to control early in the season, but most growers had good control. With the dry weather that dates back to early May at most farms, apple scab did not get a chance to spread. However, based on ornamental crabapple landscape trees that were not treated for apple scab early in spring, it was a very bad year for apple scab, as most of these trees lost most of their leaves from apple scab in the last month.

While there were a few fire blight strikes in most apple blocks, it was not a serious problem.

Pears were very hard to find this fall as a result of freeze events this spring. Pear psylla populations were very high spring and summer.

Peach harvest was short to nonexistent this season. Growers in the southern tier of counties and the Romeo, Mich., area were the only farms with a crop this season.

Leaf yellowing and drop continues in trees that did not have a crop. A few blocks have so little foliage left that it looks more like late fall in terms of the degree of foliage remaining.

Sweet and tart cherry harvest was limited only to growers in the southern tier of counties and the Romeo, Mich., area. Leaf yellowing and drop is severe in some blocks, mainly due to a combination of cherry leaf spot disease and drought.

Plums were nonexistent this season for most growers.

Small fruits

Strawberry harvest started very early this year, with most farms having a long harvest season. Newly planted fields that were watered well this summer look very good at this time. Renovated fields that were not watered well after renovation did not come through the process well this season, with many fields having holes with dead plants. Most plantings have had severe weed pressure this season.

Raspberry harvest on fall-bearing varieties continues. Spotted wing Drosophila (SWD) trap catch has hit record numbers at most farms in the last few weeks, and the number of farms that have stopped harvesting due to wormy berries has continued to grow. In some cases, growers have discovered the fruit infestations themselves and many other growers have discovered wormy fruit when they have had calls from customers reporting wormy berries. Our small fruit entomologist at Michigan State University, Rufus Isaacs, is calling this the “SWD tsunami.” I also have had a good number of growers that have had a few adults caught in traps, but when they checked for infested fruit, have found a good number of fruit infested with larvae.

If growers have not been trapping for SWD or checking for infested fruit, I am encouraging them to do so immediately. Here is some information on a simple technique for sampling for larvae in fruit using a fruit dunk flotation method: Collect a standard sample of fruit (may be fruit for marketing or suspicious fruit). Place the fruit in a plastic zip-lock bag and crush lightly to break the skin. Make a salt solution by dissolving 1 Tbsp. of salt in 1 cup of water and add this solution to the bag to cover the berries. After 30 minutes, examine the liquid to see if larvae are visible in the liquid. Larger SWD larvae will be visible as small, white pieces floating through the colored liquid. Placing this mix on a dark-colored tray is also an effective method for scoring the sample for SWD contamination. Detection of small larvae may require the use of a hand lens.

Summer raspberries experienced a total crop failure this season at most farms mainly due to a combination of freeze damage this spring and effects of prolonged drought.

Blueberry harvest started much earlier than normal and had good yields on most varieties this season. Spotted wing Drosophila-infested fruit were an issue the last two weeks of the season at a few farms where harvest came to an early end due to infested fruit.

Grape harvest is under way for Concord types.

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