East Michigan fruit update – June 26, 2018

First catch of apple maggot and spotted wing Drosophila has occurred. Sweet cherry, summer red raspberry and saskatoon harvest is underway.

First trap catch of apple maggot adults is early for east Michigan, and today, June 26, we caught our first spotted wing Drosophila. Harvest of sweet cherries, summer red raspberries and saskatoons are underway, with tart cherry harvest to follow quickly. Strawberry harvest is wrapping up to the south, except for growers with late varieties. With heat expected over the weekend, strawberry harvest will end soon for most growers.


Most of the region has received only a few tenths of an inch rain in the last week, however some growers had a few inches of rain in just a few hours. Our soils generally remain on the dry side and most of the Thumb area and our sandy sites are very dry. Soils seem to dry very quickly this season, so growers need to keep a close eye on soil moisture supplies for signs of drought stress, especially on newly planted and young fruit plantings. Many growers have started irrigation systems.

Tree fruits

Apples have continued to size well this last week, most are in the range of 1.25 to 1.75 inches in diameter, with Northern Spy being nearly 2 inches in diameter. Apple growers are continuing to see that some varieties are requiring hand-thinning. Most growers have started this process. We continue to see leaf yellowing or mottling in Honeycrisp.

There are three new pests to report in apples this week: apple maggot, green apple aphids and woolly apple aphids. The first catch of apple maggot on red sticky traps started being seen yesterday morning. Green apple aphids are beginning to feed on new leaves in many blocks. Woolly apple aphids are just starting to be seen on a few terminals. This is early in the season to see them on terminals. San Jose scale crawlers continue to be found, but the time of crawler activity will be ending soon. Two spotted spider mite numbers are quickly building this week, so growers need to do a good job of scouting for them. Brown marmorated stinkbugs are being found in low numbers in traps at more farms this week. This seems early, but apple growers need to be on the lookout for them. Apple rust mite numbers continue to build but are generally much lower than threshold numbers. Obliquebanded leafroller feeding injury on fruit continues to be found. White apple leafhopper and potato leafhopper adults are being seen for the third week on apple leaves in just a few apple blocks. Oriental fruit moth trap catches are on the rise for the start of the second generation. Codling moth crawlers are being found in a few blocks. Rosy apple aphids continue to be found in a few blocks, causing leaf curling. European red mite adults are more common this week, but still well below threshold levels.

I am starting to see apple scab lesions on fruit. Nectria twig blight continues to be found in light amounts. Just a touch of fire blight continues to be found in many orchards. At this time these strikes are limited in numbers and can easily be broken out well below the canker and disposed of. Pruners can also be used to remove the strikes, but remember that if tools are used, they must be sterilized between cuts. More powdery mildew terminal branch strikes continue to be found this week.

Pears have sized well in the past week, with most being 1.25 to 1.5 inches in diameter. All stages of pear psylla are being found in blocks where control measures have not taken place.

Peaches are mostly at 1.37 inch in diameter, pit hardening is beginning. A few more growers have reported finding brown marmorated stinkbug (BMSB) nymphs feeding on young peach fruit. There is a clear ooze coming from the site of the feeding injury. Growers need to be on the lookout for BMSB in peaches.

Sweet cherries remain mostly between 18 and 21 mm in diameter. Harvest started in the last few days at many farms. Color and fruit size is good. Birds are starting to feed heavily in sweet cherries. Spotted wing Drosophila was caught in a sweet cherry block today. Keep cover for this pest.

Tart cherries are 16 to 18 mm in diameter, with continued great color development in the past week. These too will be early this season. Some growers will begin harvest over the weekend, which is about a week ahead of normal beginning of harvest.

Plums are about the same size as last week, with European varieties being at 0.875 inch in diameter and 1.25 inch for Japanese varieties. Some European and Japanese varieties have a very light crop on them, most likely due to poor pollination.

Small Fruits

Strawberry harvest has finished for many farms to the south, with the exception of farms with late season varieties. Berry quality has seemed to improve for these late season varieties. Also, there isn’t near the thrips damage to later maturing varieties. The predicted weekend hot temperatures will most likely end harvest for most other growers. Growers should consider delaying the beginning of the renovation process until this next round of hot weather is over. I am starting to see some potato leafhopper feeding damage to newly planted berries. Where flowers buds have been removed, I am seeing a good amount of runnering take place in new plantings.

Raspberry harvest is underway for early season summer raspberries. Berries are very plentiful this season, but berry size is on the small size. Growth has slowed a bit for fall-bearing raspberries. Flower clusters are starting to form on many of the canes. They will most likely be ready to harvest early this season. Spotted wing Drosophila was caught in a sweet cherry block today. Keep cover for this pest in raspberries. Growers will need to watch closely for the first spotted wing drosophila trap catch and to begin to control it soon thereafter that catch. I am starting to see some potato leafhopper feeding damage to new or primocanes in summer raspberries. A few bramble planting have been hit hard with raspberry sawfly feeding damage.  

Blueberries have put on some growth in the past week, most are between 10 to 14 mm in diameter. Berries have not started to color yet.

Saskatoon harvest is underway for the main season varieties. Fruit have sized well in the past week, with most fruit in the range of 11 to 13 mm in diameter. Apple curculio feeding injury continues to be found, mostly in the range of three to five percent damage in commercial blocks and 60 to 70 percent damage in unsprayed plantings.

Grapes continue to put on a good growth, with concord types reaching nearly buckshot sized fruit and BB-sized fruit for vinifera types. A new pest to report this week is powdery mildew. Twospotted spider mite populations continue to slowly build.

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