Southwest Michigan fruit update – June 28, 2022

Raspberry harvest is underway. Blueberry and tart cherry harvests will begin soon.

Cranberries in full bloom.
Cranberries are in full bloom. Pollinators are present at this time. Photo by Cheyenne Sloan, MSU Extension.

Weather 

Last week was another hot week, just not as humid. Monday and Tuesday saw high temperatures in the 90s. A weak cold front passed through the region on Tuesday night, breaking the heat. The rest of the week saw temperatures fluctuate between the upper 80s and the upper 70s. Average relative humidity stayed below 70% the entire week. Trace amounts of rain were recorded on Saturday and Sunday for some stations. Otherwise, it was a dry week.

This week will be just as dry, but maybe a little cooler than last week. Most days should see high temperatures in the low to mid 80s with Thursday being the hottest day of the week. We will see low 90s across the region that day. Small chances of rain are predicted on Wednesday and again on Friday, but not much precipitation is expected.

Soils are drying out. Drought conditions are being seen just southwest of us in central Illinois and Indiana. Unless we see a change in the rain patterns, expect soils to continue drying out over the coming weeks. For fields with irrigation systems, inspection and repair now will help prevent plant stress.

With the warm week, we picked up a lot of degree days, 207 growing degree days (GDD) base 42, 151 GDD base 50.

Southwest Michigan GDD summary from March 1 through June 27, 2022 

Station 

GDD 42 F 

GDD 45 F 

GDD 50 F 

Benton Harbor (SWMREC) 

1633

1390

1027

Lawton (Lawton) 

1630

1390

1030

Fennville (TNRC) 

1493

1259

910

Average for the SW region 

1607

1367

1010

Average last week 

1400

1181

859

Tree fruit 

With the sunny weather and high evapotranspiration rates this past week, trees in drought prone areas may start showing stress as the soils continue to dry out. Light colored foliage due to nitrogen deficiency is becoming noticeable as plant reserves are being used up. 

Codling moth, oriental fruit moth, and obliquebanded leafroller are all being caught in traps. Codling moth second generation flight is expected to begin this week in many areas of our region. Egg laying will begin over the weekend. Second generation oriental fruit moth is past peak egg laying.

Peach and nectarine pit hardening has occurred in central Berrien County. Hand thinning is done in many orchards. Estimated harvest date for Redhaven for Berrien County is Aug. 1, about average. Picking of Rich May and PF-1 has begun in some sites. Rich May is showing significant amounts of red-colored flesh. The second generation flight of oriental fruit moth is winding down. Both lesser and greater peach tree borer adults are flying. There are trunk spray chemical options beyond chlorpyrifos, but read labels carefully when choosing.

Red flesh in peach.
Rich May early peach variety showing red flesh. Photo by Bill Shane, MSU Extension.

In cherries, sweet cherry harvest is underway. Montmorency tart cherry shaking will begin shortly after the Fourth of July in central Berrien County. The Enviroweather station in Bainbridge township of Berrien County has recorded nine cherry leaf spot infection periods since late April, two more than in 2021 at this same time. Spotted wing drosophila are being caught in low numbers. This is typical for this time of year. We usually see an increase in the population of this pest beginning the middle of July. So far, the warm weather the past few weeks does not appear to have sped up development of this pest.

In plums, black knot management on susceptible cultivars can be relaxed if terminal growth is generally halted.

Apple fruit in many southwest region orchards are showing small amounts of sunburn due to the 95-plus degree temperatures over the past two weeks. Varieties most affected include Honeycrisp, Red Delicious, and Zestar, Summer NAA treatment now helps to suppress biannual bearing. Hail in the Van Buren area a few weeks ago has increased fire blight symptoms. Obliquebanded leafroller flight is finishing. Second generation Codling moth flight will begin soon. Damage from the first generation of codling moth is showing up, including wet frass from larval feeding.

Sunscald in apple
Sunscald showing up on apple fruit exposed to 95-plus temperatures in mid-July in southwest Michigan. Photo by Bill Shane, MSU Extension.

Small fruit

Grapes: Many hybrids are at or past buckshot berry. Vinifera are nearing buckshot. Varieties with Labrusca in their parentage such as Concord, Niagara, and Brianna are past pea size berry. Brianna is at berry touch. Disease management of phomopsis, black rot, downy and powdery mildews are the primary focus currently. Grape berry moth flight has been winding down ahead of the next biofix. The 810 GDD biofix used for grape berry moth insecticide timing should be between July 1-4 for most growers in the region. See this article for more information on grape berry moth biofix. In wine grapes, materials to control botrytis should be included in the sprays. Downy mildew and phomopsis damage is being seen.

Black Rot in grapes.
Black rot has been seen on developing grape berries. Photo by Cheyenne Sloan, MSU Extension.

Blueberry: Early varieties are coloring up. Harvest should begin this week in some areas. Fruit set looks good in many locations. Disease focus should be on early fruit rot management. Cranberry fruitworm and cherry fruitworm flights should be finished. Weed control sprays are continuing. 

Strawberry harvest continues in some locations, but is finishing in most areas. Fruit rots are being seen. Maintain fungicide coverage to protect the leaves and help prevent fruit rots as fruit continues to ripen, especially with the heat. The heat, humidity and rain have shortened the season for some growers. Those who are done with harvest are beginning to renovate.

Bramble harvest is beginning in southern Berrien County. Maintain fungicide programs to protect from fruit rots and monitor for spotted wing drosophila so you can stay ahead of the expected population increase coming soon.

Cranberries are blooming.

Currants and gooseberries are coloring up. Champagne and red currant harvest is underway.

Hops growth continues with some varieties reaching the top wire. Some blocks that were trained early are beginning to set flowers ahead of schedule. Downy mildew continues to be a problem in susceptible varieties, even with the drier weather.

Flowers on hops.
Flowers are developing on some hops varieties. Photo by Mike Reinke, MSU Extension.

Chestnuts are blooming.

Paw paw fruit are about an inch long.

Upcoming meetings 

The Southwest Michigan Viticulture Field Day will return to the Southwest Michigan Research and Extension Center for 2022. As tradition holds, the event will be the last Wednesday of July (July 27, 2022) and will include presentations of ongoing research in southwest Michigan. The event will once again conclude with a steak dinner and local wine tasting. Registration for the Viticulture Field Day is online through the Michigan Grape Society’s website.

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