Southeast Michigan fruit regional report – August 25, 2015

Fall red raspberry harvest is in full swing, late summer apples continue to be harvested and peach and blueberry harvest is winding down at most farms.

Weather

Most of the region received rain in the last week, but total precipitation was widely scattered, ranging from 0.6 to 2.1 inches with most growers receiving around 1 inch. As a result, most of our soils have adequate to normal amounts of soil moisture.

Our seasonal growing degree day (GDD) totals have continued to bounce around from being ahead of normal, to normal, to a few days behind normal. In terms of the beginning of harvest of our fruit crops, this season we have been running a few days ahead of normal, and that continued this week with the harvest of Ginger Gold and Paula Red apples.

East Michigan GDD totals for March 1 to Aug. 24, 2015

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

2,961

2,556

1,926

Emmett (St Clair)

2,939

2,540

1,921

Flint (Genesee)

3,242

2,827

2,176

Lapeer (Lapeer)

2,977

2,576

1,950

Petersburg (Monroe)

3,127

2,712

2,064

Pigeon (Huron)

2,744

2,360

1,767

Romeo (Macomb)

3,123

2,717

2,077

Tree fruits

Apple harvest is underway for Ginger Gold and Paula Red. Zestar harvest will begin in the next few days. I will begin harvesting and analyzing apples for the Michigan State University Extension Apple Maturity Reports early next week, so look for the first Apple Maturity Report of the season to be published mid-next week with more details on apple maturity. Growers with Mollie’s Delicious are looking to begin harvest later this week and Gala harvest is expected to begin around Sept. 3 for growers in the southern areas of our region on the earliest maturing Gala strains.

Apple size at most farms continues to be very good this season, for most growers fruit are around 3 to 3.25 inches in diameter. Summer pruning continues at most farms. Retain applications to delay harvest for better fruit color and fruit size continue to be made.

With the exception of late-season worm activity, like codling moth and obliquebanded leafroller, in a few apple blocks and San Jose scale crawlers, pest pressure is winding down for the season. Woolly apple aphids are a problem in some blocks as well. Growers need to do a thorough job of scouting for this late-season worm or larvae activity that I am finding in just a few apple blocks I have visited late last week and early this week. I suggest a late-season insecticide application in these blocks for Goldens and later harvested varieties. San Jose scale second generation crawlers are being found in problem blocks and need to be controlled. European red mites seem to have been controlled nicely in most blocks by either miticide applications in hotspots or by predators. No brown marmorated stink bugs have been caught in traps this season in east Michigan at fruit or vegetable farms. Beneficial insects continue actively feeding in most apple blocks, although their numbers are starting to decline due to lack of food.

I continue seeing a few apple trees with the fungal disease called silver leaf. I have never seen this much of this disease show up in any one season. It is usually found on older, poor vigor trees, and may not show the silvered leaves ever again.

Pears continue sizing well with the largest fruit 2.75 inches in diameter. Bartletts are starting to color and harvest is expected to begin in two weeks or so.

Peach harvest is winding down for most growers. Brown rot is being found in later peach varieties. Bacterial leaf spot-infected leaves and fruit continue being seen in many peach blocks.

Tart cherry leaf yellowing from cherry leaf spot disease continues at most farms. Some trees are completely defoliated and will be prone to winter damage if we have another cold winter.

Plum harvest has mostly wrapped up for Japanese plums, and European plum harvest is expected to begin in two weeks. European plums are mostly 1.375 inches in diameter and are continuing to color well. Some blocks have a lot of bacterial spot, mostly on leaves.

Small fruits

Grape clusters are just starting to take on color in Concord types and clusters continue to fill out for the few European varieties with a crop this season. Downy mildew and powdery mildew continues being found.

Strawberry fields continue rebounding from renovation, and where additional nitrogen applications have been made, new leaves are more of a normal large size and dark green color. Growers need to keep an eye on newly planted and renovated fields for potato leafhopper infestations.

Raspberry harvest of fall raspberries is in full swing for most varieties. I continue getting calls from growers finding wormy fruit s infested with spotted wing Drosophila (SWD) worms or larva. Trap catch of SWD continues climbing in raspberries.

Blueberry harvest is winding down at most farms as berry size is starting to diminish. As is the case in fall raspberries, I am finding SWD-infested fruit at several farms where control measures were either started too late in the season or growers had longer gaps in control programs. Some farms stopped harvesting berries early due to infested berries. SWD trap catch is continuing to climb in blueberries; growers need to continue control programs through the end of harvest.

I have still not caught blueberry maggots in traps this season. Phomopsis canker and twig blight-infected canes continue being found as wilted leaves and twigs, with leaves turning light brown.

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