East Michigan fruit update – July 16, 2019

Soils remain dry across most of the region. Harvest continues for many fruit crops. A few blueberry farms have opened for picking and several farms are starting to pick a few of the bud berries on fall red raspberries.

Weather

Soils in much of our region are dry and starting to turn droughty. It is hard to believe we have gone from one of the wettest springs on record to soils being so dry. Both newly planted tree and small fruits are showing signs of drought stress. Peach and apple growth have slowed in the few weeks as well. Many growers are hoping for a nice slow inch of precipitation.

There is moisture deeper in the soil profile. However, 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. Strawberry growers may need to irrigate prior to starting renovation because the soils are so dry.

There were slow moving narrow bands of precipitation that moved through the midparts of the region on Monday afternoon, July 15, bringing a half to full inch of rain for a few lucky growers. I hope more growers receive rain through this week of hot weather.

With the heat of the last three weeks, our season has moved forward to now being three days behind normal to three days ahead of normal when looking at growing degree day (GDD) totals for region. Our Michigan State University Deerfield Enviroweather station has now reached over 2,000 GDD base 42. However, when I look at the start of harvest of our fruit crops being currently harvested, we are normal to even being ahead of normal by a few days for the typical start of harvest dates.

East Michigan growing degree day totals for March 1 to July 15, 2019

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

1,839

1,561

1,148

Deerfield (Monroe County)

2,035

1,737

1,296

Emmett (St Clair County)

1,510

1,253

878

Flint (Genesee County)

1,912

1,629

1,204

Freeland (Saginaw County)

1,778

1,510

1,105

Lapeer (Lapeer County)

1,749

1,477

1,074

Pigeon (Huron County)

1,560

1,303

925

Romeo (Macomb County)

1,883

1,603

1,186

Tree fruits

Apples have continued to size, but the rate of growth has slowed for most growers; they are mostly 1.75 to 2.5 inches in diameter. Hand-thinning continues in apples and terminal growth is starting to slow.

I have two new apple pests to report this week, Japanese beetles and apple rust mites. A few Japanese beetle adults are just starting to be seen. Apple rust mite adults are being seen in just a few blocks of apples. They are not causing any leaf bronzing yet.

Apple maggot trap catch on both yellow sticky traps and red ball traps has continued at most farms this week; however, their numbers are generally low. Low numbers of woolly apple aphids are continuing to be found in a few hot spots in a few apple blocks, a few are even moving out toward the terminals. A few European red mite adults are starting to be found, with numbers being well below the threshold. I have not found any leaf reddening or bronzing.

San Jose scale crawlers are no longer being found, but this week I have found a few hotspots where there is fruit damage. A few orchards have larvae of obliquebanded leafroller and redbanded leafroller. Codling moth trap catch was much lower this week in most blocks. White apple leafhopper adults continue to be seen at a few farms, with potato leafhopper adults being found in many apple blocks. There are no new beneficials to report this week; lady beetles, six spotted thrips and green lacewing adults continue to be found.

Cedar apple rust leaf symptoms were reported several weeks ago, but this last week symptoms are becoming more visible. No new fire blight shoot strikes were found this week. I have not seen any in younger apples yet. Apple scab fruit lesions continue to be found in more blocks this week. Powdery mildew infected terminals continue to be found in many apple blocks.

Pears are mostly at 1.25 to 1.625 inches in diameter. Pear psylla continue to be present in all stages.

Peaches are mostly the same size as last week, 1.625 to 1.75 inches in diameter for the largest sized fruit. Some early varieties are starting to see fruit color. Hand-thinning has wrapped up in peaches. A few green peach aphids continue to be found. Peach leaf curl symptoms were very common this season in many blocks, but with the new growth and effected leaves dropping to the orchard floor, trees look much better.

Sweet cherry harvest began the week before last at most farms. Harvest continues for about half of the farms, and others are winding down in the next week. Demand has been very good this season. Cherry fruit fly trap catch started to be seen around July 4, and trap catch continues. Over the weekend, a few farms started to find larvae in fruit. Some undersprayed sweet cherry blocks have brown rot showing up on fruit. Bird feeding pressure is high in both sweet and tart cherries.

Tart cherry harvest continues across the region. Cherry fruit fly trap catch started to be seen around July 4, and trap catch continues. Some blocks continue to 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 mostly 1 inch in diameter for European varieties, with some starting to color. There has been a good amount of fruit drop this past week in European plums. Japanese varieties are mostly 1.25 to 1.5 inches in diameter. Many Japanese varieties have a light crop this season.

Small fruits

Strawberry renovation has started at most farms. Many growers are irrigating prior to renovation because the ground is so dry and hard. I had a few more reports of thrips damage in strawberries in the last week. If you found symptoms of bronze-colored and seedy berries at harvest, I would appreciate hearing from you soon. You can contact me at tritten@msu.edu or 810-244-8555.

Raspberry harvest continues for summer red raspberries and black raspberries. Berries are ripening quickly with the heat. This week, many growers started picking the bud berries or berries on the shorter interior growing canes of fall red raspberries. A few spotted wing Drosophila adults continue being caught in traps. Some traps are catching very high numbers of other lookalike fruit flies this season.

Blueberry harvest started late last week or over the weekend for a few farms with early varieties. The largest fruit is 14 to 18 millimeters in diameter. Some varieties have put on a good amount of branch and leaf growth in the last three 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 is complete.

Grapes are at buckshot to the largest fruit being 11 to 13 millimeters in diameter. Grape berry moth larvae were reported feeding in grape clusters late last week. Japanese beetles are just starting to be found this week in grapes. A few growers are seeing higher numbers of twospotted spider mites this week.


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