East Michigan fruit update – June 13, 2017

Strawberry harvest continues across the region, although some farms have limited picking due to poor fruit quality. Soils remain dry at most farms.

Weather

Soils across the region remain dry, with another week with no precipitation. For most growers, it has been three weeks since the last significant rain event. Most growers are starting up irrigation systems or are getting water to newly-planted trees and small fruit crops.

Warm summer-like temperatures over the last week continued to push rapid growth in all of our fruit crops, especially in tree fruits. Our season remains ahead of normal, now five to seven days in terms of degree day totals and growth stages.

East Michigan growing degree day totals for March 1 to June 12, 2017

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

1092

890

604

Deerfield (Monroe County)

1312

1087

764

Emmett (St Clair County)

1050

853

581

Flint (Genesee County)

1216

1006

704

Freeland (Saginaw County)

1109

915

641

Lapeer (Lapeer County)

1136

935

654

Pigeon (Huron County)

961

776

527

Romeo (Macomb County)

1132

927

637

Tree fruits

Apples continue to size well, despite dry soils. In the last few days I have seen some afternoon wilting of newly planted apples. Apples are mostly at 1.125 to 1.375 inches in size. June drop has started to take place in many apple blocks in the last few days. Hand thinning continues in blocks on good sites and close to wind machines. Most farms have a spotty apple crop, with hand thinning being required in some blocks and others with just a few apples. There are a few growers that have a full apple crop. More and more apples with frost rings are being seen.

While I first reported finding a few green apple aphids in early May, this past week populations have exploded at many farms. Predators are commonly being found feeding on aphids as well. Apple rust mites are the only new apple pest to report this week.

San Jose scale male adult trap catch continues, and I am just starting to see a few crawlers. Reports from growers finding brown marmorated stink bug adults continues, mainly around buildings. These overwintering adults are not considered a pest at this time of the season, however it will become a possible pest when the nymphs from these adults begin feeding on peaches in July, and later in the season on apples. I have not seen any codling moth egg hatch yet, but it is expected any day now. This week good numbers of beneficials are being seen; new this week are green lacewing larva.  

Apple scab lesions continue to be found on leaves, although not in great amounts. Apple scab spore discharge continued during the last rain event, but with the lack of rainfall, it is hard to know if we are at the end of primary apple scab season. While the apple scab model shows that all spores are mature, we still need a rain event to tell for certain that we are at the end to primary apple scab. Powdery mildew symptoms continue to be found. I have not seen any fire blight shoot strikes yet this season.

Pears are mostly 18 to 22 millimeters in size. It is hard to find any pears in most blocks due to loss from frost. The little fruit that remains is scared with frost marks and rings. All stages of pear psylla continue to be found.

Peaches are mostly at 1.125 to 1.325 inches in size, with most growers having a good crop. Many growers have thinned peaches twice this season. A few green peach aphids continue to be found, as well as some light amounts of peach leaf curl symptoms. Oriental fruit moth trap catch has gone down in the past week. I have not found any shoot flagging yet.

Sweet cherries are at 15 to 17 millimeters in size, with the early varieties starting to mature, most likely in 10 days or so. Black cherry aphids are a new pest to report this week. Their populations have built quickly on suckers on the insides of trees in the last few days.

A few flower thrips continue to be seen. Birds, mostly robins and starlings, have been feeding heavily in these early maturing varieties. Three weeks ago it appeared that most growers had a good sweet cherry crop, however with heavy fruit drop, most growers now report just an OK crop. 

Tart cherries are mostly at 11 to 13 millimeters in size. Cherry leaf spot is a new disease to report in tarts this week, with some of the earliest leaves yellowing. Most growers report that they have a good tart cherry crop this season.  

Plums are at 22 millimeters for European types and Japanese types are at 1.125 inches in size. Some Japanese varieties have little to no crop on them this season.

Small fruits

Strawberry harvest started in the last week for most farms, with farms in the south being at the peak of harvest for the last few days. The first picking was lighter than normal at most farms, with smaller berry size than normal. I am seeing many strawberry fields that have many small berries that are starting to ripen. I am concerned that these berries will not ripen to normal size this season. I am also seeing a good amount of berries that are either misshapen, have an odd bronze color or have with many seeds gathered in one spot. Some farms have decided not to open for pick your own harvest this season due to small misshapen berries.  Their plants have not looked good for the entire season.

This poor plant growth and resulting poor berry quality was most likely due to many factors, all related to cold temperatures. We had three cold events for some areas of east Michigan that have resulted in poor berry quality. The first was a sudden cold snap the occurred on Dec. 19 with temperatures well below zero. Growers who did not have berries mulched at this time seem to have more damage.

The second was a series of cold events in mid March with low temperatures in the lower teens range. The third cold events were frost and freezes on May 8 and 9.  We also had a good amount of wind over the winter that blew most of the straw over to Ontario, Canada, leaving berries unprotected.

Lastly, recall that with cold and windy weather during the extended bloom period, pollinators had a difficult time working, causing some misshapen berries from poor pollination.

New plantings are starting to runner well. Most growers have removed flower buds in new plantings. Watch that new berries are well watered, as most fields are dry.

Slug damage is being found in a few more strawberry fields in the last week, careful scouting needs to be done now. A few tarnished plant bugs have been seen in the last few days.

Raspberry fruitlets of summer raspberry varieties continue to enlarge. Winter killed cane tips need to be tipped to good growth. Fall raspberry varieties continue to have better growth, with the longest canes at 24 inches long.

Blueberry fruit is still mostly 9 to 11 inches in size. Overall, we have a very nice blueberry crop this season at most farms. Most varieties have finally started to produce more leaf growth.

Grapes are mostly at 24 inches on new growth, with 20 percent bloom in Concord types.

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