East Michigan fruit regional report – August 23, 2016

The season-long drought that began for most growers in mid-May appears to be over, especially after another week with good precipitation.

Weather

For the second week in a row, good precipitation came to the region. This week’s average for the region was 2.3 inches, and for last week the range was 2.5 and 3.5 inches of precipitation. Over the last two weeks, most growers have received between 4.8 and 5.8 inches of precipitation. The one caveat to add is that precipitation totals have varied a great deal over very short distances, with some farms receiving as much as 8 to 10 inches over the last two weeks. Most fruit growers had not received any significant rain since mid-May.

With the rains of the last two weeks, the drought is over. Soil moisture supplies are less than normal, but more than adequate for this season of drought. Fruit size for crops yet to be harvested have seen a marked increase in the last week or so.

With the heat for the month of August, growing degree-day (GDD) totals have continued to quickly build. We are between 10 and 14 days ahead of normal for degree-day totals and five days ahead of normal for the beginning of harvest for our fruit crops.

East Michigan GDD totals for March 1 to Aug. 22, 2016

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

3,192

2,783

2,158

Deerfield (Monroe County)

3,507

3,072

2,400

Emmett (St Clair County)

3,135

2,738

2,129

Flint (Genesee County)

3,428

3,015

2,379

Freeland (Saginaw County)

3,115

2,722

2,118

Lapeer (Lapeer County)

3,145

2,746

2,137

Pigeon (Huron County)

2,911

2,533

1,954

Romeo (Macomb County)

3,304

2,895

2,268

Tree fruits

Apples are mostly 2.75 to 3.25 inches in diameter for most growers, sizing well over the past week. Color has been another matter, however, as we have not had good, cool weather for color development. There are some sunburn issues on early apple varieties, mainly for exposed fruit at the top of the tree. Growers have mostly harvested Paula Reds and Ginger Gold. Some growers are waiting for better color to do the last picking of Paula Reds. Zestar harvest is fast approaching. Some McIntosh drop is being seen. Growers continue Retain applications. Many growers are reporting bird feeding injury in many varieties of apples, mostly from crows. Fruit finish is good to excellent this season.

Codling moth trap catch for the second generation adult flight has dropped back again this week, but egg hatch is strong this week. Oriental fruit moth trap catch is up again this week; this is the third generation adult flight. Apple maggot trap catch on yellow sticky traps has been high in most blocks. Growers may need a later than normal, end of season insecticide application at this time to control all three of these pests. With codling moth flight, some seasons it is hard to tell for sure what is happening, and this is one of these years.

Apple rust mite numbers are climbing in several blocks. European red mite and twospotted spider mite numbers have generally been dropping back over the past two weeks. Brown marmorated stink bug trap catch has been seen this week at one trapping location in the Flint, Michigan, area. Michigan State University Extension advises growers be on the lookout for them throughout harvest. Beneficial numbers are building; this week I am seeing good numbers of minute pirate bugs, lacewing larvae and velvet mites.

Black rot symptoms are being seen on more fruit and leaves as well. Sooty blotch and flyspeck disease symptoms have not been seen, but I expect to see them this week.

Pears remain mostly 2.25 to 2.5 inches in diameter. Bartlett harvest is expected to begin later this week. Fruit size has been reduced due to the drought. Pear psylla numbers are high on suckers in untreated blocks.

Peach harvest is wrapping up for the main season varieties at most farms. Smaller fruit size was normal at most farms, mainly due to drought. I have not seen any brown rot symptoms, but growers who received a good amount of rain over the past two weeks may consider a brown rot fungicide application on the end of the season varieties.

Sweet cherry and tart cherry leaf drop has slowed now that we have received good rainfall. Most of the leaf drop was from drought and, to a lesser extent, from cherry leaf spot symptoms. Some sweet cherry blocks continue to have high numbers of twospotted spider mites; they are bronzing leaves.

Plums are coloring for European types, with fruit size improving to mostly 1.5 inches in diameter. They continue to color well. Japanese plum varieties are mostly harvested.

Small fruits

Grape fruit growth has taken off again in the past week; it was amazing to see so much berry and cane growth now that we have received rainfall. Concord fruit are continuing veraison and clusters of European varieties are just starting veraison. Growers should keep a close eye out for powdery mildew and downy mildew symptoms soon.

Strawberry leaves filled the row in renovated fields, and in new plantings the runners have more than filled the row, and some growers are now cutting runners. Potato leafhopper populations are building, especially in new plantings. Growers should watch for curled leaves, although this symptom can be somewhat confusing as the same symptoms can be seen with drought stress. Some weeds are also coming on strong as a result of recent rainfall; some hand-pulling is needed at this time.

Raspberry harvest continues in fall red raspberries. Berry size is starting to improve. Blackberry harvest is continuing at most farms. Growers are pruning fruiting or floricanes canes in summer red and black raspberries, and cane tipping is continuing in black raspberry and blackberries.

Spotted wing Drosophila (SWD) trap catch is very high in fall raspberries, with another big jump across the region. More farms have seen small SWD larvae in fruit and have stopped harvest for a few weeks while they bring populations under control. Growers should protect all bramble crops on a weekly basis for SWD infestation. For more details on the SWD life cycle, control strategies and specific insecticide recommendations, consult the MSU Spotted Wing Drosophila website.

Blueberry harvest is winding down at most farms. Small berry size is a problem at most farms, mainly due to drought. As in the case of raspberries, this week’s trap catch of SWD in blueberries has taken another big jump across the region. Growers should protect blueberries for SWD infestation. For more details on SWD life cycle, control strategies and specific insecticide recommendations, consult the MSU Spotted Wing Drosophila website.

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