East Michigan fruit update – May 22, 2018

Apple bloom continues across the region, leaving fire blight risk high. Strawberries are in full bloom, beginning of harvest will be much later than normal.


The southern tier of counties is still dealing with excessive rain that started the weekend before last and continued early last week, with more rainfall over this past weekend. Rainfall totals over this time are in the range of 4.5 to over 6.5 inches. There were some extended wetting events for many diseases in both tree and small fruit crops.

Continued warm temperatures have moved our season forward again this past week to a point where we are about three days behind normal to a few days ahead of normal. In terms of growing degree-day (GDD) totals, we are about five days behind normal.

East Michigan GDD totals for March 1 to May 21, 2018





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 remain in late bloom to petal fall over most of the region. Some varieties are blooming in a different sequence than in most years, for example Gala was at full bloom later this season when compared to other varieties. Also, I did not see the usual spread in bloom dates from south to north that I normally see. I was surprised to see bloom in apples last as long as it did this season.

While most growers had a good bloom in apples this year, I am concerned about the general absence of honey bees and poor weather for pollination. Wait for a week before beginning thinning to see how much of this fruit is set.

Tarnished plant bug is the only new pest to report in apples this week, their numbers are very low, however. Oriental fruit moth adult trap catch remains low for most growers, with the exception of just a few growers that traditionally have much higher catches. Redbanded leafroller and spotted tentiform leafminer trap catch has dropped off in the last week, and growers who applied a pink insecticide are no longer finding leafroller larva feeding in fruit clusters. Most growers are waiting for bloom to finish later in the week to apply their petal fall insecticide. I have not found any plum curculio adults or feeding injuries yet this season.

Most growers have had two apple scab wetting infection periods in the last week, with most areas having one of these events result in a heavy infection. I continue to catch apple scab spores with each wetting event, but the numbers of spores are starting to decline. Fire blight control has been a major issue across the region over the last week. Most growers have applied two covers of streptomycin, some three.

Pears are 5 to 11 millimeters in diameter. High numbers of pear psylla adults are being found in some blocks, and this week I am finding nymphs.

Peaches are just beginning shuck split for a few early varieties, while most are still in the shuck. I am finding a few green fruitworms in peaches.

Sweet cherries are mostly between 6 and 11 millimeters in diameter. I am finding a few black cherry aphids in sweet cherries this week.

Tart cherries are at shuck split to 6 millimeters. Some blocks have a light crop set this season.

Plums are at shuck split for European types and Japanese varieties are 4 to 8 millimeters in diameter. Some varieties have a very light crop on them, most likely due to poor pollination.

Small fruits

Strawberries are at full bloom at farms to the south and 50 to 60 percent bloom as you move to the north. It looks like we will have a late strawberry harvest this season. I have not seen any strawberry clipper injury on blossoms or young fruitlets. Be on the lookout for tarnished plant bugs. Most growers have applied one to two fungicides as strawberries are in bloom.

Raspberry canes continue to emerge from the soil in both summer and fall bearing raspberries, with the longest canes being between 12 to 14 inches in height. Flower trusses are now expanding on early flowering summer bearing floricanes.

Blueberries are at full bloom. Most growers are making bloom time fungicide applications this week.

Saskatoon fruit have set and are expanding, with a nice crop coming along this season. Be on the lookout for apple curculio feeding injury this week.

Grapes are at 4 to 8 inches of shoot growth, with flower clusters just starting to emerge. 

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