East Michigan fruit update – July 9, 2019

Soils have quickly gone from too wet all spring and early summer to now dry. Harvest of many fruit crops is underway, including sweet cherries, saskatoons, summer red raspberries, tart cherries and black raspberries.

Weather

Soils in much of our region have dried out very quickly in the last week. In the last few days I have heard many growers wishing for a nice slow inch of precipitation. In looking at the moisture levels in the upper soil profile at many farms in the last few days, I would tend to agree with them. I have started to see newly planted small fruit and tree fruit begin to show signs of moisture stress. There is moisture deeper in the soil profile, but with the excess moisture this spring, the root systems of newly planted fruit crops have not had to grow very far to find adequate moisture. There are early signs of stress in fruit trees planted in the fall.

A good amount of field work has taken place in the last two weeks. I have had many reports from fruit growers that they have just now finished planting fruit crops. This is the latest that growers have finished planting. These late planted fruit crops will need extra attention for the rest of the season.

Some fruit farms saw another inch of precipitation over the last two weeks, but most have received only a few tenths of an inch. I have had two reports of near golf ball size hail falling for over a minute in the last week.

With the heat of the last two weeks, our season has moved forward to now being three days behind normal when looking at growing degree day (GDD) totals for region. However, when I look at the start of harvest for sweet and tart cherries, summer red raspberries and black raspberries, we are normal to even being ahead of normal by a few days for the typical start of harvest dates. The start of strawberry harvest was one of our latest starts ever for many growers. There are many things about this season that don’t make sense, and this one fits right in.

East Michigan GDD totals for March 1 to July 8, 2019

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

1611

1354

976

Deerfield (Monroe County)

1795

1517

1112

Emmett (St Clair County)

1287

1052

712

Flint (Genesee County)

1676

1414

1024

Freeland (Saginaw County)

1551

1304

934

Lapeer (Lapeer County)

1533

1282

914

Pigeon (Huron County)

1340

1105

762

Romeo (Macomb County)

1648

1390

1007

Tree fruits

Apples have continued to size well this season; they are mostly at 1.5 to 2 inches in diameter. Apples across the entire region are about the same size, which is unusual. Most growers continue to feel that overall, they have a good apple crop this season. Honeycrisp is the one variety that set an uneven crop from block to block, some are very light to a few needed to be hand thinned. Hand thinning continues in apples. Terminal growth is starting to slow is apples.

Insect pest pressure in apples has picked up in the last week with three new pests to report, including apple maggot, woolly apple aphids and European red mites. Apple maggot trap catch on both yellow sticky traps and red ball traps was started to be found yesterday, which is the typical timing of the first catch for this pest. Only a few farms found trap catch. Low numbers of woolly apple aphids are starting to be found around pruning cuts and even moving out toward the terminals. A few European red mite adults are starting to be found, with numbers being well below threshold numbers. I have not found any leaf reddening or bronzing yet.

A few San Jose scale crawlers continue to be found. A few more orchards had high trap catch of adult obliquebanded leafroller, redbanded leafroller and codling moth over the last week. White apple leafhopper adults continue to be seen at a few farms, with potato leafhopper adults being found in many apple blocks. A few brown marmorated skink bug adults continue to be caught in traps, these are overwintering adults. A few blocks of apples have high numbers of spotted tentiform leaf miner second generation adults being caught in traps. Lady beetles are the only new beneficials are being seen this week, and I am continuing to find good numbers of six spotted and green lacewing adults.

Just a few new fire blight shoot strikes continue to be found in more apple blocks, most in terminals of larger trees. I have not seen any in younger apples yet. Apple scab fruit lesions continue to be found in more blocks. Powdery mildew infected terminals continue to be found in many apple blocks.

Pears are mostly 1 to 1.25 inches in diameter. Pear psylla continue to be present in all stages.

Peaches are mostly 1.625 to 1.75 inches in diameter for the largest sized fruit. Some early varieties are starting to see fruit color. Hand thinning continues in peaches. A few green peach aphids continue to be found. Peach leaf curl symptoms are very common this season in many blocks.

Sweet cherry harvest began late last week at most farms. Demand is very good this season. Cherry fruit fly trap catch started to be seen around July 4; this is a new pest in both sweet and tart cherries. However, many growers will finish harvest of sweet cherries before this pest will be a problem. There are some blocks with lots of leaf drop from cherry leaf spot disease. Some under sprayed sweet cherry blocks have brown rot showing up on fruit. Bird feeding pressure is high in both sweet and tart cherries.

Tart cherry harvest has started at several farms in the last few days. Cherry fruit fly trap catch started to be seen around July 4; this is a new pest in both tart and sweet cherries. Some blocks have low numbers of spotted wing Drosophila adult trap catch. There are blocks with heavy leaf drop from cherry leaf spot disease. Bird feeding pressure is high in both tart and sweet cherries.

Plums are 0.875 to 1 inch in diameter for European varieties and Japanese varieties are 1 to 1.25 inches in diameter. Many Japanese varieties have a light crop this season.

Small fruits

Strawberry harvest has wrapped up for most farms, a few have late season berries to harvest for one or two more pickings. The heat of the last week has made it hard to continue with harvest. Renovation has started at a few farms. A few growers had some twospotted spider mites late last week. These will most likely not survive through the renovation process. I also heard a few reports last week of gray mold in a few strawberry blocks. I had a few more reports of thrips damage in strawberries. Look out for seedy/bronze colored fruits. If you find these symptoms, I would appreciate hearing for you soon. Contact me at tritten@msu.edu or 810-244-8555.

Raspberry harvest began last week for summer raspberries. Ripening occurred quickly in summer red raspberries with the heat, catching some growers by surprise to see them ripen so quickly. Black raspberry harvest is just beginning. Fall red raspberries have small fruitlets that are continuing to size nicely. A few spotted wing Drosophila adults continue to be caught in traps. Some traps are catching very high numbers of other look-alike fruit flies this season.

Blueberry fruit have taken on a good swell in the last week, with the largest fruit being 14 to 18 millimeters in diameter. Some early varieties are starting to color. Some varieties have put on a good amount of branch and leaf growth in the last two weeks. A few spotted wing Drosophila adults continue to be caught in traps. Traps are catching a very high number of other look alike fruit flies this season.

Saskatoon harvest continues, with most farms at around 75 to 80% through harvest. Birds are also feeding heavily in saskatoons.

Grapes are at buckshot sized fruit. Some clusters have not filling in nicely. A few growers had some two-spotted spider mites late last week.


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