East Michigan fruit crop update – August 11, 2020

Harvest has begun for Red Haven and other main season peach varieties. Blueberry harvest continues across the region.


Most growers have received only a few tenths of an inch of rain in several short events in the past week. Most soils have continued to dry in the past week, and while signs of drought stress have not returned, most growers have resumed to irrigating on a regular basis in the last few days, especially in shallow-rooted fruit crops such as strawberries, fall raspberries and blueberries. Drought conditions remain for growers in the very southeast tip of the state.

For most of our region, our season has moved ahead to being 5 to 10 days ahead of normal for growing degree days and 3 to 5 days ahead of fruit crop growth stages.

East Michigan growing degree day (GDD) totals for March 1st to August 10, 2020. MSU Enviroweather.





Commerce (Oakland County)




Deerfield (Monroe County)




Emmett (St Clair County)




Flint (Genesee County)




Freeland (Saginaw County)




Lapeer (Lapeer County)




Pigeon (Huron County)




Romeo (Macomb County)




Tree fruits

Apples have continued to size for growers that have been irrigating over the last six weeks or so, for these growers most fruit are 2.5 to nearly 3 inches in diameter. For other growers, fruit sizing seems to have stalled in the last two weeks or so, with most apple fruit at 2 to 2.25 inches in diameter. Harvest of a few summer apple varieties continues. Jersey Mac harvest has started at a few farms and others will begin in the next few days. Beginning of Paula Red harvest is at least two weeks away. Handthinning has wrapped up at most farms. Bird feeding has been seen in the past week, especially crows.

There are no new insect pests to report in apples this week, but there are several insects that need to be watched closely. Apple maggot and codling moth trap catch has continued over the last two weeks. MSU Extension advises that growers will need to keep covered for both of these pests. Woolly apple aphids numbers have continued to climb in some blocks; growers are finding clumps of woolly’s on terminal branches. More growers are finding increasing amounts of San Jose scale damage in many apple blocks this week. Now is the time to keep good records of where these are being found to target oil applications next spring. Populations of twospotted spider mite continue to build, mainly along fence rows, close to woodlots and in dusty locations. Apple rust mite and European red mite populations are continuing to slowly build as well. Some limited bronzing of leaves from all three of these insects is being seen. Most blocks are still well below threshold numbers, and predator numbers continue to build to help control them. Japanese beetle populations have declined again this week.

Growers need to be on the lookout for brown marmorated stink bug insects or feeding damage in apples. I have seen a few more insects this week, but I have not seen any feeding injury yet this season. It is hard to find. Beneficial or predator numbers continue to build.

Bitter rot symptoms are starting to be seen this week in light amounts, but on several varieties. This week I am finding a few more apple blocks with pinhead apple scab on fruit and sheet scab on leaves. Sooty blotch and fly speck symptoms are being seen by more growers this week. Black rot fruit infections are even more common this week than last week.

Pears are mostly at 2 to 2.5 inches in diameter. Pear size should be good this year. We are about 3 weeks away from the beginning of Bartlet harvest.

Peach harvest is underway for Red Haven and other main season varieties. Fruit have taken on a nice swell in the past week and coloring is continuing. There has been some uneven ripening in peaches this season. I hope this diminishes with cooler temperatures.

Again this week I have found a few peach blocks with just a few late stage brown marmorated stink bug (BMSB) nymphs or very young adults. I did not find any feeding damage. We have been catching just a few BMSB in traps this week. Rusty spot was seen in some early peach varieties, however I have not seen any in Red Haven or later season varieties.

Sweet cherry leaf spot disease symptoms and leaf drop are slowing where post-harvest fungicide applications have been made.

Tart cherry leaf spot disease symptoms and leaf drop is less common than on sweets. Where post-harvest fungicide applications have been made symptoms have been reduced.

Plums have taken on a nice swell and colored well in the past week; European varieties are mostly at 1.25 inches in diameter. I expect harvest to begin in a week or so. Japanese varieties are continuing with harvest. Most plum blocks have a poor crop due to freeze/frost damage.

Small fruits

Strawberry regrowth has continued to rebound well in most renovated fields. Growers with dry soils are continuing to irrigate both renovated fields and new plantings. Newly planted strawberry rows are filling out nicely at most farms. Potato leafhopper leaf cupping damage is common in newly planted strawberries, but I am no longer finding the actual insects. Most of the leaf cupping damage is old.

Raspberry growth has responded well to recent rain events of two weeks ago for fall raspberries. Fall red raspberry fruitlets continue to develop, with some beginning to color. Harvest may be starting in the next week or so. Harvest of bud berries continues. Blackberry harvest is just a few days away from getting started.

Spotted wing Drosophila (SWD) trap catch has taken a nice jump in traps this week. Trap catch started across the region eight weeks ago but has been low up until this week. SWD protection programs need to be ongoing in raspberries.

Blueberry harvest continues on many varieties, most growers report that we are past the peak of harvest. Berry size is diminishing on mid-season varieties. The largest berries are 11 to 14 mm in diameter. Remaining berries are coloring well.

Spotted wing Drosophila (SWD) trap catch started across the region eight weeks ago, and until this week trap catch has remained low. But this week I am finding a jump in SWD trap catch. SWD protection programs need to be ongoing in blueberries. Blueberry maggot trap catch has continued for the fourth week in a row.

Grapes are at berry touch for all varieties and clusters are filling out. I have not seen any variety starting veraison yet. Japanese beetle populations have declined for the third week in a row. The third generation of grape berry moth is well along, control measures need to be underway. Downy mildew symptoms continue to be found this week.

Did you find this article useful?