East Michigan fruit update – Aug. 15, 2017

Harvest continues for peaches and summer apple varieties, with blueberry harvest ending soon. Apple varieties are maturing earlier than predicted. Dry soils remain an issue for most of the region.

Weather

Soils remain dry for most of the region, with most growers receiving only a few tenths of an inch of widely scattered precipitation over the last week. The season-long precipitation story of the “haves and have not’s” continues. Rainfall totals for the season have been extremely variable over relatively short distances. The trend also continues that the further south I travel in Michigan, the drier soils get.

There are signs of drought stress on many farms, especially on newly planted tree and small fruit crops and in the last week or so on apple size. More widely scattered, pea-sized hail was reported from thunderstorms last Friday afternoon, Aug. 11.

Our season remains two to five days ahead of normal in terms of growing degree-day (GDD) totals and even further ahead for the beginning of harvest of our summer fruit crops. See the apple section of this report for more specific details on how early our season is.

East Michigan GGD totals for March 1 to Aug. 14, 2017

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

2,809

2,417

1,816

Deerfield (Monroe County)

3,147

2,733

2,096

Emmett (St Clair County)

2,764

2,379

1,793

Flint (Genesee County)

3,004

2,605

1,988

Freeland (Saginaw County)

2,779

2,396

1,809

Lapeer (Lapeer County)

2,767

2,378

1,785

Pigeon (Huron County)

2,546

2,172

1,609

Romeo (Macomb County)

2,938

2,543

1,938

Tree fruits

Apple harvest continues for summer apple varieties. Growers have been spot-picking Paula Reds for a few days and Zestar harvest started early this week at many farms. Gingergold are a few days from the start of harvest, at least spot picking. The normal harvest date for Paula Red is Aug. 24, and for Gingergold Aug. 26. This year, the predicted harvest date for Paula Red is Aug. 19, so five days early. Many growers started spot-picking Paula’s on Aug. 12 or 14, almost two weeks early. So, late summer apple varieties are maturing even faster that we predicted. I cannot say for certain how this will play out for the main stream fall apple varieties, but they will most likely be mature ahead of normal and even ahead of the predicted dates.

Apples have continued to size well, with the largest being 3.25 inches in diameter and most being around 3 inches in size. However, there is a wide range of apple sizes on the tree this season. This will have an impact on apple maturity as well, as these smaller apples were most likely pollinated very late in our long bloom period, and therefore will mature later in the season. Apples continue to color well for this time of the season.

Most apple varieties have now set most of their terminal buds, thus summer pruning is taking place on many varieties. Apple drop continues to slowly take place as fruits continue to enlarge, mostly pushing off the limb; this is mostly the larger sized fruit.

Brown marmorated stink bugs continue to be caught in traps at several orchards, and in the last week a few apples were fed on by brown marmorated stink bugs. This feeding damage is hard to find, and I did not find any brown marmorated stink bugs nymphs or adults in the same trees where I found the damage. Sometimes this damage is hard to distinguish from bitter pit, hail damage and feeding by native stink bugs.

If you had brown marmorated stink bug fruit damage in 2016 or are finding them feeding on apples, now is the time to control them with a full cover. They seem to prefer to feed mostly in the tops of trees and on green varieties at this time of the season, but not always.

Apple maggot trap catch numbers are climbing for the third week in a row. Trap catch is occurring on farms where soils are dry, which is unusual. Codling moth trap catch numbers have remained high in non-mating disrupted blocks for the third week in a row.

Bitter pit is occurring in a few varieties; this is a new disorder to report this week. Black rot-infected fruit are visible in several blocks, mostly in the same blocks where it was a problem last season. Sooty blotch and flyspeck symptoms continue to be seen in more blocks.

Pears have taken on a nice swell in the past week, many are just over 2.25 to 2.5 inches in size with much of the fruit having frost marks. Harvest of some early season varieties has begun at many farms for those few growers with a good crop. Sooty mold from pear psylla feeding is being found in many blocks.

Peach harvest continues for late-season varieties. Many growers report they will finish up harvest in a week. Older leaves continue to turn yellow, mostly caused from a touch of bacterial spot with some leaf yellowing attributed to the effects of drought stress. There are a few terminals flagging from oriental fruit moth.

Sweet cherry leaf yellowing and drop continues, mainly from cherry leaf spot. This is being found mostly in the top middles of large trees, indicating a spray coverage problem. I am also seeing a few limbs dying from bacterial canker.

Tart cherry leaf yellowing and drop continues, mostly from cherry leaf spot. Some trees are nearly defoliated.

Plum harvest continues for Japanese varieties. Stanley and other European varieties continue to color and size well.

Small fruits

Strawberry regrowth is continuing from the renovation process where soil moisture has been adequate. Most strawberry varieties are responding well to renovation. New plantings continue to runner well.

Potato leafhopper populations continue to build in new plantings where they have not been controlled. Michigan State University Extension advises keep an eye on the newest foliage in newly planted fields for signs of continued leaf curling from this insect feeding.

Raspberry harvest is complete for summer red raspberry varieties, with the exception a few late season varieties. Fall raspberry harvest is expected to begin in a week. Fall bearing black raspberry harvest continues, as does blackberry harvest.

Spotted wing Drosophila is being caught in traps in summer and fall raspberries in very high numbers. Begin SWD protection programs soon in fall raspberries.

Blueberry harvest is winding down quickly for many varieties this week. Berry size is small and berries are losing their flavor. Overall, many farms had a record blueberry crop this season.

SWD trap catch numbers continue to be very high in blueberries, so if you are still harvesting, control programs need to continue as well. Blueberry maggot trap catch continues this week, especially on farms that have had good rains in the last few weeks.  

Phomopsis canker continues to be found at several farms, causing sudden wilting and death (flagging) of canes.

Grape fruit clusters continue to fill out for Concord types and Vinifera types are starting veraison.

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