Southeast Michigan fruit regional report – July 22, 2014

Raspberry and blueberry harvest continues across the southeast region.


Dry weather was the case in the southeast region in the last week. Our season remains close to normal to slightly ahead of normal for growing degree day (GDD) totals and ahead of normal for the beginning of harvest of our fruit crops.

Soil moisture supplies remain adequate for most fruit growers. However, a few growers are starting to irrigate again as soils are on the dry side. These small, widely scattered areas have missed the last few rain events. For this last group of growers, it has been surprising how quickly soils have gone from too much to too little moisture.

East Michigan GDD totals from March 1 to July 21, 2014





Commerce (Oakland)




Emmett (St Clair)




Flint (Genesee)




Lapeer (Lapeer)




Petersburg (Monroe)




Pigeon (Huron)




Romeo (Macomb)




Tree fruits

Apples have continued to size very well in the last week, although their growth rate seemed to have slowed compared to the past month. Apples in the Flint, Michigan area are mostly 1.875 to 2.125 inches. Hand-thinning operations are winding down at most farms. Summer pruning continues for most varieties as their terminal buds have been set for the season. Leaf tissue samples for nutrient analysis can be taken now.

With the exception of a few mite hotspots and some leaf curling from potato leafhoppers, there has not been much insect pressure in apples in the last week. I am finding three species of mites in isolated spots in a few apple varieties: European red mites, two-spotted spider mites and apple rust mites. Predators are generally keeping them under control. Hopperburn and leaf cupping from high numbers of potato leafhoppers are being found in a few apple blocks. Green apple aphids continue to be seen in the last few weeks.

Generally, there has been little to no apple maggot, codling moth or oriental fruit moth trap catch in the past week. Japanese beetle numbers are slowly increasing in all fruit crops, but with lower than normal numbers for this time of the season. A few fruit have San Jose scale stings with their characteristic red to purple discoloration around the feeding site. Good predator numbers continue to be seen in most apple blocks. I have not seen any symptoms of sooty blotch and fly speck diseases.

Pears have not sized much in the past week. Most are 1.5 to 1.875 inches in diameter.

Peach growers are continuing to remove dead trees and pruning less severally winter-damaged trees. 

Sweet cherry pruning is taking place. Usually, this post-harvest window is less invigorating than late winter or spring pruning. Trees that have filled their space can be modestly trimmed in the post-harvest to early August window with less risk of bacterial canker than the traditional delayed dormant pruning time. Cherry fruit fly trap catch continues.

Tart cherry leaf drop from cherry leaf spot is continuing to be seen. It is early in the season for this leaf drop to begin. Michigan State University Extension recommends growers apply a post-harvest fungicide to control this disease.

Plum size has remained about the same with European plums mostly at 1 inch and Japanese varieties close to 1.5 inches.

Small fruits

Grapes are at berry touch to cluster tightening for Concord and Niagara varieties, with a wide range of fruit development stages this season. Wine grapes continue to have extensive cane death in most varieties, with new shoots continuing to emerge from latent buds on the trunk. It is still too early to prune these back. Grape berry moths are continuing to be caught in traps and a few Japanese beetles are being found in grapes.

Strawberry renovation is complete at most farms and continues for a few growers. Review the herbicide options during renovation time. Many growers have seen much quicker regrowth of leaves this season, some within four days after mowing. This is the result of adequate to above adequate soil moisture supplies. With leaf growth occurring so quickly, it has made herbicide applications very difficult for some growers.

Raspberry harvest continues for summer red and black fruiting varieties. Limited harvest of fall-bearing varieties is being seen on a few shorter interior canes. Fall-bearing varieties are growing very well this season, with very long canes at most farms. Some are approaching 6 feet in length. This could make harvesting operations difficult at farms that do not trellis their berries.

First trap catch of spotted wing Drosophila (SWD) has been reported at a number of farms, but only in traps in adjacent fence rows to raspberries. I believe that there is such an abundant crop of wild hosts available this season that SWD are feeding on these other fruits. When these alternative food sources are gone, I expect SWD to quickly move into cultivated berry crops.

Again, we have not seen any SWD trap catch in raspberries. Fruit will need to be protected when first trap catch occurs in traps in fields. Consult recommendations in the “Spotted Wing Drosophila Management Recommendations for Michigan Raspberry and Blackberry Growersguide at the MSU Spotted Wing Drosophila website.

We continue to find Japanese beetles in both summer and fall raspberries. Gray mold was reported at a few farms on early berries, but I have not seen any gray mold this week.

Blueberry harvest continues across the region, with some farms needing to stop harvest for a few days to allow more berries to ripen. Demand for pick-your-own-blueberries has been very strong so far this season. No blueberry maggots have been caught in traps, but are expected soon. A few Japanese beetles continue to be found in blueberries. Spotted wing Drosophila infestations are a threat to blueberries as well as raspberries. See the raspberry section of this report for details on SWD trap catch and recommendations. Consult recommendations in the “Spotted Wing Drosophila Management Recommendations for Michigan Blueberry Growers guide at the MSU Spotted Wing Drosophila website.

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