Southwest Michigan fruit update – June 25, 2024 

Harvest is harvesting!

Grapes hanging from a tree.
Grapes are anywhere from buckshot to nearing berry touch in the region. Photo by Cheyenne Sloan, MSU Extension.

Weather 

The weather this week is going to be cooler than last week but still warm and wet, with the greatest chances of rain on Friday, June 28. There is a chance for damaging winds and hail from this morning's storms (June 25). Hail would justify an immediate streptomycin spray in apples, assuming the farm is not in an area where strep resistance is present; only the west half of Berrien County is where strep still works.

Southwest Michigan growing degree day (GDD) summary from March 1 – June 24, 2024

Station

GDD 42 F

GDD 45 F

GDD 50 F

Benton Harbor (SWMREC)

1,893

1,602

1,173

Lawton (Lawton)

1,815

1,548

1,143

Fennville (TNRC)

1,653

1,391

1,004

Grand Junction

1,783

1,517

1,119

Average for the SW region

1,773

1,507

1,110

There is no weather report this week.

Tree fruit

Spotted wing drosophila flies are showing up in more traps and soft fruit. Protective insecticide sprays should be renewed following rains. Red marks on apple are showing up indicating, that San Jose crawlers from the first generation flight are settling down to form new scales. Brown marmorated stink bug numbers are still low. Rainfall totals since April 1 are quite different for the various areas of southwest Michigan. Allegan and Cass counties are behind in rainfall compared to central and lower Berrien County.

Red marks on an apple fruit.
Red marks on apple fruit are from first generation San Jose scale crawlers transforming into scales and forming waxy scale covers. Photo by Bill Shane, MSU Extension.

Peach and nectarine leaf loss due to bacterial spot is becoming significant on susceptible varieties on sandy sites. Harvesting of early varieties such as Rich May is underway. Peaches are ready for harvesting about seven days earlier than normal. Oriental fruit moth trap numbers may be on the rise for the second generation flight. The peak of the second generation is usually less well defined than the first. Brown rot protection is important as fruit color near harvest. Application of bacterial spot control materials, such as mycoshield, at this time is probably not very effective.

In cherries, commercial shaking of tart cherries in Berrien County has begun. Brix seems to be very good this year. Birds are feeding on both sweet and tart cherries. Spotted wing drosophila larvae are showing up in low numbers in area fruit, so insecticide protection is important. Brown rot and cherry leaf spot control continue to be the primary disease management concerns now. Leaf loss due to cherry leaf spot is very apparent in some area orchards.

Apple fruit hand thinning is generally done. The sooty blotch and flyspeck  model on Enviroweather predicts that wetter areas such as Berrien County could see symptoms sooner than the drier Allegan and Cass counties. Summer diseases such as bitter rot and white rot could be showing up on fruit soon. Orange-yellow leaf spots due to juniper rust are showing up in some orchards. Protection against codling moth larvae should be ongoing. Oriental fruit moth trap catches for the second generation are perhaps starting to increase. This generation targets both peach and apple fruit. Apple maggot flies are showing up in yellow sticky traps and are a concern for sandy sites.

Pear insect concerns are pear psylla and obliquebanded leafroller. Mycosphaerella and Fabraea leaf spot are common summer diseases on pear that can be confused with pear scab.

Small fruit

In grapes, grape berry moth second generation is starting. Adult moth catch has increased in the last few days. According to the grape berry moth model (using May 19 as biofix and the Southwest Michigan Research and Extension Center as the site), the second generation should be laying eggs this week. Egg hatch should begin early next week. Typical timing for products that can impact eggs and hatching larvae, such as Intrepid and Altacor, would be at the start of egg hatch.

Earlier this week, the Michigan Department of Agriculture and Rural Development (MDARD) released an announcement of spotted lanternfly larvae caught in Monroe County, Michigan. The site, near Detroit, is not near significant grape acreage. See “Spotted Lanternfly Confirmed in Monroe County” from MDARD for more information.

Downy mildew infections are now being seen. With the rains and cooler weather over the next week, be sure to maintain coverage for this and other diseases. This window from bloom until bunch closure is critical for cluster protection for the remainder of the season.

Blueberry harvest is underway in Van Buren County. Disease focus should be on early fruit rot management. Phomopsis cane collapse continues to appear. In these hot, dry conditions, you need to irrigate. If you have overhead irrigation, focus on protecting against anthracnose. See: Blueberry growers need to focus on Anthracnose fruit rot as bloom ends. Consider irrigating at night when the temperatures are cooler rather than the day so the wetting periods occur during cooler periods. Use systemic fungicides, which are absorbed into the plant, reducing fungicide wash off from sprinkler applications.

Cranberry fruitworm, cherry fruitworm, spotted wing drosophila and blueberry maggot have all been caught. Spotted wing drosophila flies are showing up in more traps and soft fruit. Protective insecticide sprays should be renewed following rains.

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Ripe blueberries in a bush.
Ripe blueberries (which were very tasty). Photo by Cheyenne Sloan, MSU Extension.

Strawberry harvest is done in Berrien and Van Buren counties. It is time to renovate perennial strawberry beds.

Upcoming meetings 

The MSU Controlled Atmosphere (CA) Clinic on July 17 in Muskegon, Michigan, is organized by the MSU Department of Horticulture every other year to pass on new information relating to CA storage and warehousing of apple and other temperate fruit. This will be of primary interest to apple growers and storage operators.    

The meeting this year features four internationally recognized leaders in apple postharvest science: Christopher Watkins (New York), Jennifer DeEll (Ontario), Carolina Torres (Washington State University) and David Rudell (U.S. Department of Agriculture Agricultural Research Service – Wenatchee) and Randy Beaudry (MSU). Sign up here.   

The 2024 Michigan Viticulture Field Day is back for its 35th year. It will be held at the Southwest Michigan Research and Extension Center on July 31. Come for the education, stay for the steak dinner and local wine tasting. New this year, we are adding a second day for just the wine makers. The Michigan Enology Experience will be down the street from Southwest Michigan Research and Extension Center at the Lake Michigan College Welch Center the day after Viticulture Field Day on Aug. 1. We will talk wine production and tour some local wineries and see how they manage some of the challenges of winemaking in Michigan. Registration is available online

Planning ahead for hot weather  

The following information is from the MSU College of Human Medicine. 

With a hot Michigan summer upon us, it is important to be mindful that hot weather can be dangerous while working outside. The heat produced by your body while working plus high outdoor temperatures makes it more likely for your body to overheat. To prevent overheating, do the following: drink plenty of fluids; take frequent breaks in the shade, and if possible, reschedule high energy tasks for earlier or later in the day. 
 
Call 911 immediately if severe symptoms of overheating occur such as confusion, slurred speech, fainting, nausea/vomiting, rapid pulse, seizures, hot dry skin, or heavy sweating. Then, move the person to a cool place and help lower their temperature with a cool wet cloth and/or cool bath. Do not leave the person alone. Death can occur if the body does not cool down, so it is essential to have a plan before such symptoms occur.  

 

This work is supported by the Crop Protection and Pest Management Program [grant no 2021-70006-35450] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. 

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