East Michigan fruit crop report – July 25, 2017

Spotted wing Drosophila populations are very high for this time of season, and apple maggots are starting to be caught in traps. Hail damage is more common than reported a few weeks ago.


Rainfall over the region has been extremely variable for the last two weeks, with precipitation totals for most fruit farms ranging from 0.4 to 2.9 inches in an average of five rain events. Soil moisture supplies also vary widely across the region, with farms just a few miles apart ranging from very dry soils to too much water. Where soils are dry, growers are starting to water newly planted tree and small fruit crops.

I reported two weeks ago that the region had hail, mainly from thunderstorms on Friday, July 7. Unfortunately, the hail was more widespread than first reported. Hail has been reported in the Romeo, Flushing, Dexter and Ann Arbor, Michigan, areas. Some farms suffered a total loss of this year’s crop.

Our season remains about four to five days ahead of normal in terms of growing degree-day (GDD) totals and the beginning of harvest of our summer fruit crops.

East Michigan GGD totals for March 1 to July 24, 2017





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 are mostly 2.5 to nearly 3 inches in size for the largest fruit, however there is a wide range of fruit size this season. Where moisture is adequate, apples have continued to size well over the last two weeks. Apples continue to color well, especially McIntosh and related varieties. Hand-thinning continues, but is mostly wrapped up. Some terminal buds are now set in a few apple varieties.

Lodi and other summer apples are being harvested. Jersey McIntosh harvest is expected to begin in 10 days.

Apple maggot, a new insect to report this week, trap catch started on yellow sticky traps late last week and yesterday, July 24, the first catch on a red ball trap. This first trap catch on either trap is about two to three weeks later than normal. Other parts of the state report very high apple maggot trap catch in the past week. Twospotted spider mites are another new pest to report this week, being found in isolated hotspots in several types of tree fruits, but mostly in apples and plums. European red mite numbers build in a few apple blocks, especially where road dust or dry soils are an issue.

Potato leafhopper and white apple leafhopper numbers are building where they have not been controlled in the past few weeks, with leaf cupping and white mottling of leaves common in some blocks.

Japanese beetle numbers continue building in several fruit crops. However, where is has been controlled, numbers are declining. Woolly apple aphids are moving from pruning cuts to terminal branches. There are not as many beneficial insects as there were a few weeks ago.

Sooty blotch and flyspeck are new diseases to report this week in apples. Another new disease to report, black rot, is starting to be found on a few fruit. Traces of new fire blight strikes are showing up, mostly in bearing apple blocks. Cedar apple rust remains a problem in under-sprayed apple blocks, although I am seeing very little in well-maintained blocks. Apple scab lesions continue being found on leaves and fruit. Powdery mildew symptoms are apparent.

Pears are mostly 1.625 inches in size, with much of the fruit having frost marks. All stages of pear psylla are active, with close to a third of the fruit on some varieties having sooty mold from this pest.

Peach harvest of early varieties is underway at a few farms. Summer Serenade is being harvested. Most other varieties are starting to color, with most being 1.5 to 2 inches in size. Leaves and fruit in a few blocks have a touch of bacterial spot.

Sweet cherry harvest has wrapped up.

Tart cherry harvest has wrapped up. I had several reports over the weekend of spotted wing Drosophila (SWD) infested fruit, so most growers stopped harvest when they discovered SWD in fruit. Cherry leaf spot was found in most tart cherry blocks, causing leaf yellowing and premature leaf drop. Leaf drop is extensive in some blocks.

Plums have taken on a nice swell, they are mostly 1.25 inches in size for European types, and Japanese varieties started harvest, like Methley. Overall, this season’s plum crop is extremely variably, with some varieties having little to no fruit this season. Twospotted spider mites are another new pest to report this week, being found in isolated hotspots in several types of tree fruits, but mostly in plums and apples.

Small fruits

Strawberry renovation has wrapped up and some varieties are starting to regrow, while most others may need more soil moisture to begin the regrowth process. New plantings continue to runner well.

Potato leafhopper populations continue to build in new plantings where they have not been controlled. Keep an eye on the new foliage in newly planted fields for signs of continued leaf curling from potato leafhoppers.

Raspberry harvest continues for summer red raspberry varieties, although we are past the peak of harvest. Fall raspberry varieties continue having good growth, with most canes 36 to 40 inches long. The bud berries on shorter canes continue to fruit, with the main crop starting to size well and even some early color development.

SWD are being caught in traps in summer raspberries in very high numbers. I have had many reports of infested fruit. Control measures should be underway in summer raspberries for this most troublesome pest.

Blueberry harvest continues for Blueray and Bluecrop, with the rest of the varieties continuing to size and color well in the past few weeks. Overall, we have a very nice blueberry crop this season at most farms.

SWD are being caught in very high numbers in traps in blueberries. I have had several reports of SWD infested fruit in the past few days, causing a stop in harvest operations. Control measures should be underway in blueberries. I have not caught any blueberry maggot, but I am expecting to see catch any day now.

Phomopsis canker is a new disease to report in blueberries this week, with sudden wilting and death (flagging) of canes being seen, mostly in Bluecrop.

Grapes are at berry touch for Concord and Vinifera types.

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