East Michigan fruit update – Aug. 13, 2019

Red Haven peach harvest will begin in the next few days across the region. Many fruit farms have dry soils.


Many growers are hoping for some precipitation as soils have dried at many farms over the last two to four weeks. Rain has come to a few fruit farms, but only in narrow bands or pockets. The sod in many orchards has turned brown and newly planted tree and small fruits are showing signs of drought stress. Later maturing blueberry and fall red raspberry varieties have seen a reduction in berry size at many farms over the last few weeks due to drought.

Our season has continued to move forward with the heat of the last month, to now being five to 10 days ahead of normal when looking at growing degree day (GDD) totals for most of the region. The tip of the Thumb is the only area of east Michigan that remains a few days behind normal.

East Michigan growing degree day totals for March 1 to Aug. 12, 2019





Commerce (Oakland County)




Deerfield (Monroe/Lenawee County)




Emmett (St Clair County)




Flint (Genesee County)




Freeland (Saginaw County)




Lapeer (Lapeer County)




Pigeon (Huron County)




Romeo (Macomb County)




Tree fruits

Apple harvest of Jersey Mac and other summer apple varieties continues. Most apples are 2.5 to 3 inches in diameter. Most apple varieties have set their terminal buds in the last few weeks, however a few varieties (like Honeycrisp) have started to put on a late season flush of growth.

I have no new apple pests to report this week. Apple rust mite numbers have picked up considerably in the last two weeks, now causing bronzing in many apple blocks. Potato leafhopper adults are being found in many apple blocks, some causing extensive leaf curling. Codling moth larvae feeding injury is being seen in a few apple blocks and trap catch is generally on the rise across the region. A few more woolly apple aphids are being found in hot spots in apple blocks and a few are moving out toward the terminals, but overall I am not seeing high numbers of woolly apple aphids as I had expected based on very high populations in many blocks last fall. Trap catch of apple maggot has dropped off in the last two weeks, perhaps due to dry soils at most farms. Green apple aphid numbers have dropped off as terminal buds are setting in most varieties. Japanese beetle adult populations were lower last week, however this week their numbers seem to be picking up again. A few European red mite and twospotted spider mite adults continue to be found. I am not seeing any blocks with high enough numbers to warrant controlling them. Obliquebanded leafroller, oriental fruit moth and redbanded leafroller trap catches are generally low at this time.

There are no new beneficials to report this week, and generally their populations have been declining in August. Lady beetles, six spotted thrips and green lacewing adults continue to be found.

Necrotic leaf blotch and black rot are the only new diseases to report in apples this week. While I have not seen any leaf drop from necrotic leaf blotch yet, I am just starting to see irregular spots on Golden Delicious leaves. Black rot (also referred to as frogeye leaf spot or blossom end rot) fruit rot symptoms started to show up about 10 days ago. While cedar apple rust symptoms were first started to be seen the second week of June, many growers are finding more leaf symptoms in the last two weeks. Powdery mildew infected terminals continue to be found in many apple blocks. Keep an eye on the sooty blotch and fly speck model on the Michigan State University Enviroweather website, as we are above 240 hours of wetting at most of our sites.

Pears are mostly 1.75 to 2.25 inches in diameter. Growers are continuing to remove suckers from pears. Late last week I saw my first ever leaf spotting on pears from cedar apple rust. This disease also causes some leaf scorching symptoms. Pear psylla continue to be present in all stages.

Peach harvest began a few weeks ago on early varieties and will start in a few days for Red Haven. Split pit was an issue in some early varieties. Fruit have taken good color and a good swell in the last two weeks; they are mostly 2.5 to 3 inches in diameter for the largest sized fruit. Many varieties are showing signs of uneven ripening or maturity. I believe this the result of the long bloom period in peaches this season. I am also continuing to see some oriental fruit moth feeding damage in fruit from this second generation and especially where thinning was not adequate and peaches are touching each other. Terminal flagging or tip feeding damage from the first generation is still visible.

Tart cherry leaf drop from cherry leaf spot disease continues at a rapid pace. Fungicide applications are being made to slow the spread of this disease. Some trees are almost completely defoliated from cherry leafspot disease.

Plums are mostly 1.125 to 1.25 inches in diameter for European varieties, with good fruit coloring in the last week and much less fruit drop compared to a week earlier. Shiro Japanese plums are coloring well and are mostly 2.25 inches in diameter. Many Japanese varieties have a light crop this season.

Small fruits

Strawberry regrowth is coming along nicely where precipitation or irrigation has been adequate. Newly planted strawberries are runnering well. Several new plantings have severe leaf curling or cupping from potato leafhopper adult feeding.

Raspberry harvest is slowly ramping up for fall red raspberry growers. Blackberries are in full bloom. High trap catch of spotted wing Drosophila adult trap continues in fall red raspberries. Control measures should have started two three weeks ago at most farms and will need to continue to the end of harvest.

Blueberry harvest continues, harvest for most growers is half to three-quarters complete. Most farms have a nice crop this season. High trap catch of spotted wing Drosophila adults continues in blueberries. Control measures should have started over two weeks ago at most farms and will need to continue to the end of harvest. I am seeing a few canes begin to die from Phomopsis canker.

Grapes are at berry touch this week. Grape berry moth larvae are feeding in grape clusters. Japanese beetles continue to be found in greater numbers this week. A few growers are seeing higher numbers of twospotted spider mites. Black rot symptoms are more common this week. Powdery mildew and downy mildew symptoms continue to be seen on leaves.

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