East Michigan fruit update – June 6, 2017

Strawberry harvest is underway for growers in the southern parts of the region and will begin over the weekend or early next week for others. Soils are dry at many farms.

Weather

Warm temperatures again last week pushed rapid growth in all of our fruit crops, finally including strawberries. Our season remains three to seven days ahead of normal in terms of growing degree-day totals and growth stages.

Most of our region has received little to no rain over the last week. Many of our fruit farms are reporting dry soils. We are in need of some good rain events. Some growers are starting up irrigation systems. Strawberries are in the greatest need for irrigation.

East Michigan growing degree day totals for March 1 to June 5, 2017

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

896

716

464

Deerfield (Monroe County)

1096

892

604

Emmett (St Clair County)

844

669

432

Flint (Genesee County)

998

809

542

Freeland (Saginaw County)

889

716

478

Lapeer (Lapeer County)

930

750

503

Pigeon (Huron County)

761

598

383

Romeo (Macomb County)

919

735

481

Tree fruits

Apples continue to size well, most are 0.875 to 1.125 inches in size. I have not seen any June drop. Some growers are starting to hand-thin in some blocks on good sites and close to wind machines. Bloom has ended in newly planted trees so, while the risk of fire blight trauma infection in the leaves and tender shoots is still a concern, at least the risk of blossom infection has ended.

While reports of crop loss from the May 8 and 9 frost and freeze events are still coming to me, some growers are reporting a few more apples than they thought they had a few weeks ago. Most of the damaged fruit has dropped. A few growers still have a full apple crop. More and more apples with frost rings are apparent.

San Jose scale is the only “new” pest to report this week in apples, however I saw my first plum curculio stings on apples this week and obliquebanded leafroller trap catch has started. San Jose scale male adult trap catch started last week. This pest has been on the rise over the last five years and many growers are trying hard to get it under control this season. Most growers biofixed for San Jose scale last week as well. Now is the time to check for San Jose scale crawler activity using double-sided sticky tape placed around limbs.

While I first reported finding plum curculio on May 16 when using beating trays, this week I am finding just a bit of fruit stinging. Obliquebanded leafroller larvae were first reported on April 25, and this week growers are seeing adult trap catch, some with very high numbers.

Last week I reported brown marmorated stink bug on a trap, and since then I have had numerous reports from growers finding them in and around buildings and in orchards. 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 eggs hatch, but it is expected any day now. Beneficials are being found; new this week include lady beetle adults and eggs, velvet mites and minute pirate bugs.

Apple scab lesions are on leaves, although most of the lesions appear to be burnt out. Scab spore discharge continues with each rain event so we are still in primary apple scab season. While the apple scab model shows that all spores are mature, we still need a few more rain events for the remaining spores to be released. Powdery mildew symptoms are being seen, and I have not seen any fire blight shoot strikes.

Pears are mostly 16 to 30 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 25 to 30 millimeters in size, with most growers having a good crop. Many growers have thinned peaches, however most will need to go back in for a second round of thinning, as there is still too much fruit on the tree. Peaches are at pit hardening.

A few green peach aphids were found, as well as some light amounts of peach leaf curl symptoms. Oriental fruit moth trap catch continues in high numbers in most non-mating disrupted blocks. I have not found any shoot flagging.

Sweet cherries are 15 to 17 millimeters in size, with most of the smaller sized fruit still dropping off. There has been a good amount of fruit drop over the last two weeks. While two weeks ago it appeared most growers had a good sweet cherry crop, with this heavy fruit drop most growers now report just an OK crop. A few flower thrips have been found.

Tart cherries are mostly 10 to 11 millimeters in size. We are at pit hardening. Most growers report they have a good tart cherry crop this season.

Plums are 20 millimeters for European types and Japanese types are 1 inch in size. Some Japanese varieties have little to no crop on them this season.

Small fruits

Grapes are mostly between 16 and 18 inches of new growth with the longest canes at 24 inches. Flower clusters continue to elongate and I expect bloom next week.  

Strawberry harvest started late last week or over the weekend for growers in the southern parts of our region. The first picking was light, with smaller berry size than normal. For growers in the mid parts of the region, harvest is expected to begin this weekend or early next week. A few flowers remain open in later varieties.

Over the last 10 days or so, strawberry growers started to see improved leaf growth—finally. This poor plant growth was mainly related to cold temperatures in March and the rest of spring and cooler than normal soil temperatures.

Many strawberry fields have many small berries that are starting to ripen. I am concerned these berries will not ripen to normal size this season. There is also a good amount of berries that are either misshapen or have many seeds gathered in one spot. I believe this is caused from poor pollination. Remember that with cold and windy weather during bloom, pollinators had a difficult time working.

Slug damage was found in a few strawberry fields. Michigan State University Extension advises careful scouting now. A few spittlebugs were found this week, but populations are not high enough to be concerning. I have not seen any strawberry clipper or tarnished plant bug damage in strawberries this season.

Raspberry shoot growth continues on summer bearing raspberries, with fruitlets now formed. Fall raspberry varieties have better growth after been frosted and burning back in the May 8 and 9 freezes. The longest canes are about 20 inches in length, with most being 12 to 15 inches.

Blueberry fruit is mostly 9 to 11 inches in size. Overall, we have a very nice blueberry crop this season at most farms. I am still concerned some blueberry varieties do not have nearly as much leaf growth as normal. 

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