Southeast Michigan fruit regional report – July 7, 2015

First trap catch of apple maggot and spotted wing Drosophila was this past week. Growers are harvesting sweet and tart cherries, summer red raspberries, blueberries and strawberries.

Weather

Our season was generally dry for spring, then very wet for most fruit farms in June and now back to dry soils. The last week has been dry and hot for most of the region. Our season is running three to six days ahead of normal for growing degree day (GDD) totals for most of east Michigan. In terms of the beginning of harvest for tart cherries and early maturing blueberries, our season is about five days ahead of normal for most fruit farms across the region.

East Michigan GDD totals for March 1 to July 6, 2015

Location

GDD 42

GDD 45

GDD 50

Commerce (Oakland)

1,641

1,383

 998

Emmett (St Clair)

1,603

1,351

 977

Flint (Genesee)

1,813

1,545

1,140

Lapeer (Lapeer)

1,685

1,432

1,049

Petersburg (Monroe)

1,795

1,527

1,124

Pigeon (Huron)

1,465

1,228

 879

Romeo (Macomb)

1,710

1,451

1,057

Tree fruits

Apples continue to size very well this season, most are 1.875-2.25 inches in diameter. Hand-thinning continues for most apple growers. Overall, our apple crop is shaping up to be better than most growers expected several weeks ago.

The first trap catch of apple maggots on yellow sticky traps was July 3, and they are being seen at many farms. There have not been any trap catches on red sticky traps. Apple maggots generally take about 10 days to begin to lay eggs in fruit after first trap catch on yellow sticky traps. San Jose scale crawlers have pretty much waxed over in the past week, and damage on fruit is just starting to show up. The crawler control window is now closed. I am finding a few very small obliquebanded leafroller, oriental fruit moth and codling moth larvae feeding in very small terminal leaves at just a few farms. Growers need to do a good job of scouting for these larvae. Oriental fruit moth adult trap catch has jumped up this week; this should be the end of first generation adult flight.

A few spotted tentiform leafminer second generation adults are flying. Japanese beetle adults continue to be seen, still mostly as solitary insects and not clustering or clumping up. A few potato leafhopper adults and curled leaves as a result of their feeding injury continue to be seen, as do a few green apple aphids and rosy apple aphids. A few masses of woolly apple aphids continue to be found, moving from pruning wounds to suckers in the interior of the tree.

European red mite adult and egg numbers are starting to build in a few apple blocks, mostly on the inside middles of larger trees. The threshold has jumped to 10 adult mites per leaf and most blocks are well below this number. No brown marmorated stink bugs have been caught in traps this season, but I am finding a few other adults of other stink bug species. Good numbers of beneficial insects continue to actively feed in most apple blocks. This week, good numbers of lady beetle adults, stigmaeid mites and tachinid flies are being found.

Widely scattered fire blight strikes and apple scab lesions continue to show up. Powdery mildew-infected twigs continue to be seen in a few apple blocks. The leaf stage of black rot, known as frogeye leaf spot, is being found in more apple blocks these past few weeks, even in young apple blocks.

Pears are mostly 1.5 inches in size. All stages of pear psylla continue to be seen.

Peaches are 2.25-2.625 inches for those few growers with a crop this season; pit hardening has begun. Growers continue to hand-thin peaches and prune winter-damaged trees, removing dead and dying trees. Green peach aphids continue to be found in a few blocks. Bacterial leaf spot-infected leaves continue to be seen in many peach blocks, especially in blocks with no crop this season where pest controls have been reduced.

Sweet cherry harvest continues with some varieties seeing fruit cracking. Bird feeding is a problem in most blocks. Most growers have brown rot under control. Spotted wing Drosophila (SWD) were caught in a trap in a sweet cherry block yesterday, July 6. No cherry fruit flies have been caught in traps.

Tart cherry harvest began over the weekend at most farms. Cherry leaf spot-infected leaves are yellowing badly at some farms, with a fair amount of leaf drop on trees with a big crop on them. Michigan State University Extension advises growers to control for cherry leaf spot at this time. Birds are being seen in tart cherries. No cherry fruit flies have been caught in traps.

Plums have taken on swell the past week, with European plums mostly at 1 inch in diameter and Japanese plums at 1.25-1.5 inches in diameter. A few Japanese plum varieties are starting to color. Some blocks have a lot of bacterial spot, mostly on leaves. Black knot continues to be seen on wild and unsprayed plum trees.

Small fruits

Grapes are almost marble-sized fruit for Concord types. European varieties are at buckshot for the few growers with a crop this season. Japanese beetle adults continue to be seen, still mostly as solitary insects and not clustering or clumping up. Downy mildew has been seen at a few more farms this week.

Strawberry harvest has wrapped up for all but a few growers. Growers are waiting for soils to dry some before beginning the renovation process. Most growers found this season to be very challenging as a result of heavy rains throughout the first three weeks of June. Berry quality from heavy rainfall was an issue for many growers, with some varieties taking on a pinkish cast, a water-soaked part of the berry (mostly on the shoulder of the largest berries) and some growers also reported berries having a fermented smell. Demand for wholesale, ready-picked and pick-your-own strawberries was very strong this season. Many wholesale and ready-picked berry growers had a hard time finding enough labor this season, with a few reports of ripe berries going unharvested.

Raspberry harvest of summer fruiting types is in full swing, as is black raspberry harvest. Fall red raspberry canes continue to put on good new growth. This season, I am finding lots of flower buds or “bud berries” being formed at this time on the shorter lateral canes of fall raspberries. These early berries are not a part of the main crop. Spotted wing Drosophila (SWD) have not been caught in raspberry traps, but they have been caught in sweet cherry traps.

Blueberry harvest of early maturing varieties started in the last few days at a few farms, the earliest on record for some farms. I was surprised at how fast berries ripened in the past week. Berries have taken on a nice swell in the past week, with most of the larger berries 18-20 millimeters in diameter. Japanese beetle adults continue to be seen, still mostly as solitary insects and not clustering or clumping up. Blueberry maggots have not been caught in traps. Spotted wing Drosophila (SWD) have not been caught in blueberries traps, but they have been caught in sweet cherry traps.

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