Southeast Michigan fruit regional report – July 23, 2013

Spotted wing Drosophila trap catch in sweet cherries was just confirmed this morning. Harvest is underway in blueberries, plums and apples, and winding down in summer red and black raspberries. Blackberry harvest is quickly approaching.


A number of slow-moving thunderstorms rolled across the region in the last week, bringing high volumes of precipitation to some fruit farms. Unfortunately, there was also some hail reported in these thunderstorms as well. Most others received another 0.5 inches of rain. A few fruit farms have only seen a few tenths of an inch of rain over the past four weeks. This season, more than most, seems to be one of fruit farms getting either too much or not enough precipitation. Soil moisture supplies are generally adequate at most fruit farms.

With all of the heat of the last week and where soil moisture supplies are adequate, fruit has put on a great deal of growth in the past week. Even with the heat of last week, our season is still running just a bit behind normal again in growing degree day (GDD) totals. We are back to normal when I look at growth stages and the start of harvest of our fruit crops.

East Michigan GDD totals for March 1 to July 22





Commerce (Oakland)




Emmett (St Clair)




Flint (Genesee)




Lapeer (Lapeer)




Petersburg (Monroe)




Pigeon (Huron)




Romeo (Macomb)




Tree fruits

Apples continue to size well where soil moisture supplies have been adequate; in the Flint, Mich., area they are mostly 2.25 to 2.5 inches in diameter. Harvest of Lodi and a few other summer apple varieties continues. In last week’s report, I noted there was some off-color Honeycrisp fruit developing signs of sunscald. Indeed, there is some sunscald in this and a few other varieties. I see this most often on trees that do not have an abundance of leaves this season. Hand-thinning in apples has wrapped up at most farms and continues at others.

I continue to catch a few apple maggots, all on yellow sticky cards. Most growers have applied a border spray to control the first catch that started on July 3 or 4 in the region, and are considering a second border spray early next week to control apple maggot. San Jose scale crawler scars have been seen on fruit in many apple blocks. Most years this fruit scaring is seen later in the season after the second generation. In many blocks, no San Jose scale was present on fruit two years ago, and with no crop last season, it is unusual to see them come in so quickly.

I am continuing to catch low numbers of oriental fruit moth adults in traps; this is the start of the second generation flight. Low numbers of codling moth continue to be caught in traps. Obliquebanded leafroller larvae continue to be found in a few apple blocks; larvae seem to be either very small or very large at this time. Apple rust mite bronzing continues to be seen, but their numbers are going down. European red mite and two-spotted spider mite eggs and a few adults continue to be seen in low numbers. Wooly apple aphid populations continue to be high in a few apple blocks. Japanese beetles continue to be seen, mostly in low numbers. There continues to be high numbers of predators being seen this season.

Sooty blotch and fly speck symptoms were seen yesterday (July 23) at a few farms. Twig infections of powdery mildew continue to be seen, mainly on inside suckers. More and more apple scab continues to show up at most farms, both on leaves and fruit.

Pears are 1.5 inches at most farms where growers have a crop.

Peach harvest continues on early varieties. Most have good size. Split pit is very common this season on these early varieties. Fruit, twigs and branches continue to ooze from bacterial spot infection. X-disease continues to be seen.

Sweet cherry harvest is complete. Spotted wing Drosophila have been caught in traps in sweet cherries at two farms this past week. This was confirmed this morning (July 23). Two males were caught at one farm and two females at the other. They have not been trapped in other fruit.

Cherry fruit fly trap catches have been high in the past week; a post-harvest insecticide application may be required to reduce populations for next year. Cherry leaf spot disease symptoms were seen two weeks ago, but it seems to be arrested with the application of a fungicide. A second fungicide application is needed in these blocks.

Tart cherry harvest is complete at most farms. No spotted wing Drosophila have been trapped in tart cherries, only sweets. Cherry leaf spot disease symptoms have been seen for two weeks in tart cherry blocks, with yellowing leaves dropping to the orchard floor. A few trees have dropped almost all of their foliage and appear as they would in late fall.

Plums remain 1 inch in size for European types and some are continuing to color. Japanese types are now being harvested.

Small fruits

Strawberry renovation is complete at most farms, except where soils have been wet. In these wet fields, Michigan State University Extension is encouraging growers to delay renovation until soils have dried. Potato leafhopper feeding and leaf curling is being seen in most new plantings. Newly planted berries are runnering well.

Raspberry harvest is winding down for summer red and black raspberries. Blackberry harvest is expected to begin in the next week or so. Some farms have an abundance of lateral canes or “bud berries” this season that are continuing to mature, and a few of these berries are ready to harvest. These early berries are not a part of the main crop. We see this phenomenon more some years than others. Growers need to keep an eye for early spotted wing Drosophila infestations on these early bud berries.

Japanese beetle populations continue to slowly build in raspberries, especially in fall red raspberries. Leaf curling from potato leafhoppers is being seen in both new and established raspberry plantings. No spotted wing Drosophila have been trapped in brambles in southeast Michigan this season, but we had first trap catch in sweet cherries in the last week. Growers need to be on the lookout for trap catch.

Blueberry harvest continues on early maturing varieties. Most of the main season varieties are continuing to color. Blueberry maggot trap catch on yellow sticky traps continues with some plantings having high numbers. No spotted wing Drosophila have been caught in blueberries in southeast Michigan this season, but we had first trap catch in sweet cherries in the last week. Growers need to be on the lookout for trap catch. Birds, mostly robins, continue to feed in most blueberry plantings.

Grape cane growth continues at a rapid pace. Japanese beetle populations continue to slowly build in grapes in a few plantings. Grape berry moths continue to be caught in traps. Downy mildew was been seen on grape leaves in several more grape plantings in the past week.

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