Southeast Michigan fruit regional report – July 30, 2013

Spotted wing Drosophila were caught in traps in raspberries at a few more east Michigan fruit farms in the past few days.


Cooler temperatures have been welcomed by most fruit growers, with the exception of blueberry growers who are looking for more heat to speed the ripening process. With good soil moisture supplies, fruit have continued to size well the past few weeks.

More slow moving thunderstorms moved across the region in the last week, bringing high volumes of precipitation to some fruit farms. Most others received another 0.75 inches of rain. A few fruit farms have only seen a few tenths of an inch of rain over the past month. Soil moisture supplies are generally adequate at most fruit farms.

Our season is still running just a bit behind normal in terms of 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 growing degree day totals for March 1 to July 29





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 2.5 inches in diameter. Harvest of Lodi and a few other summer apple varieties continues. With cooler to cold nighttime temperatures, some apple varieties have colored a great deal in the past week; examples include Jonathon, Red Delicious and Empire.

I continue to catch a few apple maggots all on yellow sticky cards. I have not caught any apple maggots on a red sphere trap this season. Most growers have applied a border spray to control apple maggots. Low numbers of codling moth continue to be caught in traps; I had expected to see these numbers begin to climb this past week for the start of the second generation adult flight. Cool temperatures must be delaying this flight.

I am continuing to catch low numbers of oriental fruit moth adults in traps; this is the start of the second generation flight. I am continuing to see a few green apple aphids on inside suckers. Wooly apple aphid populations continue to be high in a few apple blocks. Potato leafhopper leaf curling is much more common this week. Fall webworm nests are just starting to be seen at a few farms. San Jose scale crawler scars have been seen on fruit in many apple blocks. Obliquebanded leafroller larvae continue to found in a few apple blocks.

Apple rust mite bronzing continues to be seen, but their numbers are continuing to drop. European red mite and two-spotted spider mite eggs and a few adults continue to be seen in low numbers. Japanese beetles continue to be seen, mostly in low numbers. No brown marmorated stink bugs have been trapped or reported in the region this season. There continues to be high numbers of predators being seen this season, in the last week many lacewing eggs and ladybird beetle pupa are being found.

Sooty blotch and fly speck symptoms were seen more commonly in the last week. 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 have put on a swell of growth this past week, most are 1.875 inches. Pear psylla populations have been very high at many farms these past few weeks.

Peach harvest continues on early varieties. Most have good size; however, split pit is very common this season on these early varieties. No brown marmorated stink bugs have been trapped or reported in the region this season. Fruit, twigs and branches continue to ooze from bacterial spot infection. X-disease continues to be seen.

Sweet cherry and tart cherry harvest is complete. Cherry fruit fly trap catches have dropped back where a post-harvest insecticide application was made. Cherry leaf spot disease symptoms were seen two weeks ago, but it seems to be arrested with the application of a fungicide. A few tart cherry trees have dropped almost all of their foliage and appear as they would in late fall.

Plums have sized and continued to color for European types with most being 1.25 inches in diameter. Japanese varieties continue to be harvested.

Small fruits

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

Raspberry harvest is complete for summer red and black raspberries and blackberry harvest is now underway at most farms in the southern part of the region. A few fall red raspberry farms are now beginning to harvest berries known as “bud berries” or berries growing on short canes from lateral shoots. These early berries are not part of the main crop. We see this phenomenon more some years than others.

Spotted wing Drosophila have been trapped in brambles at several farms in the last week, so growers need to be on the lookout for first trap catch at their farm. 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.

Blueberry harvest continues on many varieties. Blueberry maggot trap catch on yellow sticky traps continue, with some plantings having high numbers. No spotted wing Drosophila have been caught in blueberries in east Michigan this season, but we had first trap catch in sweet cherry and brambles in the last two weeks. Growers need to be on the lookout for first trap catch at their farm. Birds, mostly robins, continue to feed heavily 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 and powdery mildew continue to be seen in many grape plantings in the past week.

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